MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Biomacromolecules' source. Mon, 06 Feb 2012 13:31:34 +0100 http://www.medworm.com/index.php?rid=5658709&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22300335%26dopt%3DAbstract Authors: Zhang F, Zuo B, Fan Z, Xie Z, Lu Q, Zhang X, Kaplan DL Abstract Silk fibroin (SF) nanofibers, formed through electrospinning, have attractive utility in regenerative medicine due to the biocompatibility, mechanical properties and tailorable degradability. The mechanism of SF electrospun nanofiber formation was studied to gain new insight into the formation and control of nanofibers. SF electrospinning solutions with different nanostructures (nanospheres or nanofilaments) were prepared by controlling the drying process during the preparation of regenerated SF films. Compared to SF nanospheres in solution, SF nanofilaments had better spinnability with lower viscosity when the concentration of silk protein was below 10%, indicating a critical role for SF morphology, and in pa... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658709 Fri, 03 Feb 2012 05:00:00 +0100 5658709 http://www.medworm.com/index.php?rid=5658711&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22300287%26dopt%3DAbstract Authors: Gehmayr V, Sixta H Abstract Endoglucanase treatment of pulp for the adjustment of viscosity and the increase in pulp reactivity is a promising step in the concept for the beneficial production of dissolving pulps from paper grade-pulps. In order to promote the commercial applicability of these enzymes, the influence of pulp properties such as carbohydrate composition, pulp type and cellulose morphology on the enzymatic degradability of a pulp was examined. High contents of hemicelluloses and lignin were shown to impair the accessibility of the cellulose to the enzymes. Due to the elevated swelling capacity of cellulose II, conversion of the cellulose morphology from I to II upon alkaline treatments showed a large increasing effect on the cellulose accessibility and enzymat... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658711 Thu, 02 Feb 2012 05:00:00 +0100 5658711 http://www.medworm.com/index.php?rid=5658710&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22300304%26dopt%3DAbstract Authors: Wong SY, Han L, Timachova K, Veselinovic J, Hyder MN, Ortiz C, Klibanov AM, Hammond PT Abstract Polyelectrolyte multilayer films assembled from a hydrophobic N-alkylated polyethylenimine and a hydrophilic polyacrylate were discovered to exhibit strong antifouling, as well as antimicrobial, activities. Surfaces coated with these layer-by-layer (LbL) films, which range from 6 to 10 bilayers (up to 45 nm in thickness), adsorbed up to 20 times less protein from blood plasma than the uncoated controls. The dependence of the antifouling activity on the nature of the polycation, as well as on assembly conditions and the number of layers in the LbL films, was investigated. Changing the hydrophobicity of the polycation altered the surface composition and the resistance to protein a... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658710 Thu, 02 Feb 2012 05:00:00 +0100 5658710 http://www.medworm.com/index.php?rid=5658716&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22295868%26dopt%3DAbstract Authors: Bellusci M, Francolini I, Martinelli A, D'Ilario L, Piozzi A Abstract Microbial lipase from Candida rugosa was immobilized by physical adsorption onto an ethylene-vinyl alcohol polymer (EVAL) functionalized with acyl chlorides. In order to evaluate the influence of the reagent chain-length on the amount and activity of immobilized lipase, three differently long aliphatic fatty acids were employed (C8, C12, C18), obtaining EVAL functionalization degrees ranging from 5% to 65%. The enzyme-polymer affinity increased with both the length of the alkyl chain and the matrix hydrophobicity. In particular, the esterified polymers showed a tendency to give segregated hydrophilic and hydrophobic domains. It was observed the formation of an enzyme multilayer at both low and high prote... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658716 Wed, 01 Feb 2012 05:00:00 +0100 5658716 http://www.medworm.com/index.php?rid=5658715&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22295902%26dopt%3DAbstract Authors: Osorio-Madrazo A, Eder M, Rueggeberg M, Pandey JK, Harrington MJ, Nishiyama Y, Putaux JL, Rochas C, Burgert I Abstract Agarose hydrogels filled with cellulose nanowhiskers were strained in uniaxial stretching under different humidity conditions. The orientation of the cellulose whiskers was examined before and after testing with an X-ray laboratory source and monitored in situ during loading by synchrotron X-ray diffraction. The aim of this approach was to determine the process parameters for re-orienting the cellulose nanowhiskers towards a preferential direction. Results show that a controlled drying of the hydrogel is essential to establish interactions between the matrix and the cellulose nanowhiskers which allow for a stress transfer during stretching and thereby prom... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658715 Wed, 01 Feb 2012 05:00:00 +0100 5658715 http://www.medworm.com/index.php?rid=5658714&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22296556%26dopt%3DAbstract We present the synthesis of dual-responsive (pH and temperature) magnetic core-shell nanoparticles utilizing the grafting-from approach. First, oleic acid stabilized superparamagnetic maghemite (γ-Fe2O3) nanoparticles (NP's), prepared by thermal decomposition of iron pentacarbonyl, were surface-functionalized with ATRP initiating sites bearing a dopamine anchor group via ligand exchange. Subsequently, 2-(dimethylamino)ethyl methacrylate (DMAEMA) was polymerized from the surface by ATRP, yielding dual-responsive magnetic core-shell NP's (γ-Fe2O3@PDMAEMA). The attachment of the dopamine anchor group on the nanoparticles´ surface is shown to be reversible to a certain extent, resulting in a grafting density of 0.15 chains per nm² after purification. Nevertheless, the grafted NP´s show ex... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658714 Wed, 01 Feb 2012 05:00:00 +0100 5658714 http://www.medworm.com/index.php?rid=5658713&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22296572%26dopt%3DAbstract Authors: Zhu J, He P, Lin L, Jones DR, Marchant RE Abstract The extracellular matrix (ECM) is an attractive model for designing synthetic scaffolds with a desirable environment for tissue engineering. Here, we report on the synthesis of ECM-mimetic poly(ethylene glycol) (PEG) hydrogels for inducing endothelial cell (EC) adhesion and capillary-like network formation. A collagen type I-derived peptide, GPQGIAGQ (GIA)-containing PEGDA (GIA-PEGDA) was synthesized with the collagenase-sensitive GIA sequence attached in the middle of the PEGDA chain, which was then copolymerized with RGD capped-PEG monoacrylate (RGD-PEGMA) to form biomimetic hydrogels. The hydrogels degraded in vitro with the rate dependent on the concentration of collagenase, and also supported the adhesion of human umb... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658713 Wed, 01 Feb 2012 05:00:00 +0100 5658713 http://www.medworm.com/index.php?rid=5658712&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22296594%26dopt%3DAbstract Authors: Wen Y, Grondahl L, Gallego MR, Jorgensen L, Møller EH, Nielsen HM Abstract Dermatan sulfate (DS) is a glycosaminoglycan (GAG) with a great potential as a new therapeutic agent in tissue engineering. The aim of the present study was to investigate the formation of polyelectrolyte complexes (PECs) between chitosan and dermatan sulfate (CS/DS) and delivery of DS from PEC-containing alginate/chitosan/dermatan sulfate (Alg/CS/DS) microspheres for application in tissue regeneration. The CS/DS complexes were initially formed at different conditions including varying CS:DS ratio (positive:negative charge ratio), buffer and pH. The obtained CS/DS complexes exhibited stronger electrostatic interaction, smaller complex size and more stable colloidal structure when chitosan was in la... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658712 Wed, 01 Feb 2012 05:00:00 +0100 5658712 http://www.medworm.com/index.php?rid=5658719&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22292933%26dopt%3DAbstract Authors: Vigliotta G, Mella M, Rega D, Izzo L Abstract The synthesis of novel star-like hetero-arms polymers A(BC)n containing m-PEG (block A), methylmethacrilate (MMA) and non quaternized 2-(dimethylamino)ethyl methacrylate (DMAEMA) (blocks BC) is here reported. We demonstrated that copolymer films with comparable amounts of DMAEMA have antimicrobial properties strongly depending on the topological structure (i.e. the number of arms) of the composing copolymers. We interpret the highest antimicrobial activity of A(BC)2 with respect to A(BC)4 and linear copolymers (respectively, A(BC)2 ≥ A(BC)4 > A(BC)) as probably due to the formation of strong hydrogen bonds between close amino-ammonium groups in the A(BC)2 film. Strong hydrogen bonds seem to be somewhat disfavored in the ca... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658719 Tue, 31 Jan 2012 05:00:00 +0100 5658719 http://www.medworm.com/index.php?rid=5658718&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22292968%26dopt%3DAbstract Authors: Longobardi S, Picone D, Ercole C, Spadaccini R, De Stefano L, Rea I, Giardina P Abstract Fungal hydrophobins are amphipathic, highly surface-active and self-assembling proteins. The class I hydrophobin Vmh2 from the basidiomycete fungus Pleurotus ostreatus seems to be the most hydrophobic hydrophobin characterized so far. Structural and functional properties of the protein as a function of the environmental conditions have been determined. At least three distinct phenomena can occur, being modulated by the environmental conditions. 1- When the pH increases or in the presence of Ca2+ ions, an assembled state, beta-sheet rich, is formed; 2- when the solvent polarity increases the protein shows an increased tendency to reach hydrophobic/hydrophilic interfaces, with no detecta... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658718 Tue, 31 Jan 2012 05:00:00 +0100 5658718 http://www.medworm.com/index.php?rid=5658717&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22293015%26dopt%3DAbstract Authors: Kurniawan NA, Wong LH, Rajagopalan R Abstract Collagen networks, the main structural/mechanical elements in biological tissues, increasingly serve as biomimetic scaffolds for cell behavioral studies, assays, and tissue engineering, and yet their full spectrum of nonlinear behavior remains unclear. Here, with self-assembled type-I collagen as model, we use metrics beyond those in standard single-harmonic analysis of rheological measurements to reveal strain-softening and strain-stiffening of collagen networks both in instantaneous responses and at steady state. The results show how different deformation mechanisms, such as deformation-induced increase in the elastically active fibrils, nonlinear extension of individual fibrils, and slips in the physical cross-links in the n... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658717 Tue, 31 Jan 2012 05:00:00 +0100 5658717 http://www.medworm.com/index.php?rid=5658723&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22288730%26dopt%3DAbstract Authors: Molinos M, Carvalho V, Silva DM, Gama FM Abstract Dextrin, a glucose polymer with low molecular weight, was used to develop a fully resorbable hydrogel, without using chemical initiators. Dextrin was first oxidized (oDex) with sodium periodate and then cross-linked with adipic acid dihidrazide, a nontoxic cross-linking molecule. Furthermore, a new bidimensional composite hydrogel, made of oxidized dextrin incorporating dextrin nanogels (oDex-nanogel), was also developed. The oDex hydrogels showed good mechanical properties and biocompatibility, allowing the proliferation of mouse embryo fibroblasts 3T3 cultured on top of the gel. The gelation time may be controlled selecting the concentrations of the polymer and reticulating agent. Both the oDex and oDex-nanogel hydrogels ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658723 Mon, 30 Jan 2012 05:00:00 +0100 5658723 http://www.medworm.com/index.php?rid=5658721&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22288825%26dopt%3DAbstract Authors: Lin SY, Zhao WY, Tsai HC, Hsu WH, Lo CL, Hsiue GH Abstract The sterically polymer-based liposomal complexes (SPLexes) were formed by cationic polymeric liposomes and pH-sensitive diblock copolymer were studied for their capabilities in improving the stability with high efficiency of siRNA delivery. The SPLexes were formed a dual-shelled structure and uniform size distribution. The PEGylated outer shell could mitigate the phagocytosis and reduce the cytotoxicity. Moreover, the folated SPLexes improved 42.9 times of accumulation in vitro and 1.7 times tumor uptake in vivo in contrast with non-folated SPLexes. The protonated copolymer at low pH would improve the siRNA released into cytoplasm following SPLexes fusion with the endo/lysosome membrane and inhibited the protein ex... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658721 Mon, 30 Jan 2012 05:00:00 +0100 5658721 http://www.medworm.com/index.php?rid=5658720&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22288884%26dopt%3DAbstract Authors: Johnson RN, Kopeckova P, Kopecek J Abstract High-molecular-weight, branched N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers were synthesized and conjugated with Fab' fragments of the anti-CD20 antibody, 1F5. This produced multivalent conjugates with varying valency (amount of Fab' per macromolecule) targeted to the B-cell antigen CD20. The apoptotic activity of the conjugates was screened against several B-cell lymphomas with varied expression levels of CD20 (Raji, Daudi, Ramos, Namalwa, and DG-75). The multivalent conjugates had the strongest activity against cells that had the highest expression of CD20, and failed to demonstrate any measurable activity against lymphomas that did not express the antigen. Furthermore, there was an apparent dose-dependent response to t... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658720 Mon, 30 Jan 2012 05:00:00 +0100 5658720 http://www.medworm.com/index.php?rid=5658722&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22288777%26dopt%3DAbstract Authors: Nguyen MN, Lebarbé T, Zouani OF, Pichavant L, Durrieu MC, Héroguez V Abstract This work reports on the synthesis of titanium bone implants functionalized with nanoparticles containing Arg-Gly-Asp-Cys peptide (RGDC) and shows the adhesion behavior of cells seeded on these materials. RGDC peptides were first conjugated to a norbornenyl-poly(ethylene oxide) macromonomer (Nb-PEO). Then, functional nanoparticles (NPs) with a size of about 300 nm and constituted of polynorbornene (PNb) core surrounded by poly(ethylene oxide) shell were prepared by Ring-Opening Metathesis Polymerization (ROMP) in dispersed medium. The grafting density of these NPs on the titanium surface is up to 2 NPs/µm² (80 pmol of RGDC per cm² of NP surface). Cell adhesion was evaluated using pre-osteobl... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658722 Sat, 28 Jan 2012 05:00:00 +0100 5658722 http://www.medworm.com/index.php?rid=5658725&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22283424%26dopt%3DAbstract Authors: Ito M, Teramoto Y, Nishio Y Abstract A dynamic control of the cholesteric coloration and optical clarity of aqueous (hydroxypropyl)cellulose (HPC) lyotropics is attainable under a weak electric field by employing a fluctuating ionic additive as P and T(c) shifter (P, cholesteric pitch; T(c), cloud point). The present Article demonstrates some examples of time-evolving gradation in reflection color and transparency for HPC liquid crystals containing various N-alkyl-substituted methylimidazolium salts ([CnMim][X]); this was perceivable when each anisotropic solution was sealed in a layer form between parallel slide glasses spaced by a pair of carbon electrodes and then electrified with a direct circuit. The electrooptical phenomenon was interpreted as being primarily due to ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658725 Fri, 27 Jan 2012 05:00:00 +0100 5658725 http://www.medworm.com/index.php?rid=5658724&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22283444%26dopt%3DAbstract Authors: Ago M, Okajima K, Jakes JE, Park S, Rojas OJ Abstract Lignin-based fibers were produced by electrospinning aqueous dispersions of lignin, poly(vinyl alcohol) (PVA), and cellulose nanocrystals (CNC's). Defect-free nanofibers with up to 90 wt% lignin and 15% CNCs were achieved. The properties of the aqueous dispersions, including viscosity, electrical conductivity, and surface tension were examined and correlated to the electro-spinnability and resulting morphology of the composite fibers. A ternary lignin-PVA-water phase diagram was constructed as a tool to rationalize the effect of mixing ratios on the dispersion electro-spinability and morphology of the resulting fibers. The influence of reinforcing CNCs on the thermal properties of the multi-component fibers was investig... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5658724 Fri, 27 Jan 2012 05:00:00 +0100 5658724 http://www.medworm.com/index.php?rid=5638998&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22276990%26dopt%3DAbstract Authors: Shinoda R, Saito T, Okita Y, Isogai A Abstract The influence of 2,2,6,6-tetrametylpiperidine-1-oxyl (TEMPO)-mediated oxidation of wood cellulose and the mechanical disintegration of oxidized cellulose in water on degree of polymerization determined by viscosity measurement (DPv) and the apparent length of the TEMPO-oxidized cellulose nanofibrils (TOCNs) was investigated. DPv values decreased from 1270 to 500-600 with increasing addition of NaClO in the TEMPO-mediated oxidation stage. The DPv values were further decreased by mechanical fibrillation in water. There is a linear relationship between the average fibril length and DPv; the lengths of TOCNs can be approximated from DPv using 0.5 M copper ethylenediamine as a solvent of both the cellulose and oxidized celluloses i... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5638998 Thu, 26 Jan 2012 05:00:00 +0100 5638998 http://www.medworm.com/index.php?rid=5638997&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22277017%26dopt%3DAbstract Authors: Zhu C, Zheng M, Meng F, Mickler FM, Ruthardt N, Zhu X, Zhong Z Abstract Reversibly shielded DNA polyplexes based on bioreducible PDMAEMA-SS-PEG-SS-PDMAEMA triblock copolymers were designed, prepared and investigated for in vitro gene transfection. Two PDMAEMA-SS-PEG-SS-PDMAEMA copolymers with controlled compositions, 6.6-6-6.6 kDa and 13-6-13 kDa, were obtained by reversible addition-fragmentation chain transfer (RAFT) polymerization of dimethylaminoethyl methacrylate (DMAEMA) using CPADN-SS-PEG-SS-CPADN (CPADN: 4-cyanopentanoic acid dithionaphthalenoate; PEG: 6 kDa) as a macro-RAFT agent. Like their non-reducible PDMAEMA-PEG-PDMAEMA analogues, PDMAEMA-SS-PEG-SS-PDMAEMA triblock copolymers could effectively condense DNA into small particles with average diameters less than... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5638997 Thu, 26 Jan 2012 05:00:00 +0100 5638997 http://www.medworm.com/index.php?rid=5638999&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22276949%26dopt%3DAbstract In conclusion, shell-crosslinking is highly recommended even for glassy micelles for an efficient cellular uptake at low concentrations. PMID: 22276949 [PubMed - as supplied by publisher] (Source: Biomacromolecules) Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5638999 Wed, 25 Jan 2012 05:00:00 +0100 5638999 http://www.medworm.com/index.php?rid=5639000&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22268547%26dopt%3DAbstract Spatial Glass Transition Temperature Variations in Polymer Glass: Application to a Maltodextrin-Water System. Biomacromolecules. 2012 Jan 23; Authors: van Sleeuwen RM, Zhang S, Normand V Abstract A model was developed to predict spatial glass transition temperature (Tg) distributions in glassy maltodextrin particles during transient moisture sorption. The simulation employed a numerical mass transfer model with a concentration dependent apparent diffusion coefficient (Dapp) measured using Dynamic Vapor Sorption. The mass average moisture content increase and the associated decrease in Tg were successfully modeled over time. Large spatial Tg variations were predicted in the particle, resulting in a temporary broadening of the Tg region. Modulated Differential Scanning C... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5639000 Mon, 23 Jan 2012 05:00:00 +0100 5639000 http://www.medworm.com/index.php?rid=5639003&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22263638%26dopt%3DAbstract Authors: Martín L, Castro E, Ribeiro A, Alonso M, Rodriguez-Cabello JC Abstract The possibility of obtaining different self-assembled nano-structures in reversible systems based on elastin-like block co-recombinamers is explored in this work. The results obtained show how an evolution from a more common micellar structure to a hollow vesicle can be attained simply by changing the block arrangements and lengths, even when other molecular properties, such as molecular weight or mean polarity, remain essentially unchanged. This work sheds light on the possibility of obtaining hollow nano-objects, based on elastin-like recombinamers, which can assemble and disassemble in response to a change in their surroundings. This kind of system can be an example of how high precision in the gene... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5639003 Sat, 21 Jan 2012 05:00:00 +0100 5639003 http://www.medworm.com/index.php?rid=5639002&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22263670%26dopt%3DAbstract Synthesis and characterizations of <i>in situ</i> cross-linkable gelatin and 4-arm-PPO-PEO hybrid hydrogels via enzymatic reaction for tissue regenerative medicine. Biomacromolecules. 2012 Jan 21; Authors: Park KM, Lee Y, Son JY, Oh DH, Lee JS, Park KD Abstract <i>In situ</i> cross-linkable hybrid hydrogels composed of gelatin and 4-arm-polypropylene oxide-polyethylene oxide (Tetronic) was developed as an injectable scaffold for tissue regeneration. The gelatin was modified by hydroxyphenyl propionic acid (HPA) and the Tetronic was conjugated with tyramines (Tet-TA). The hydrogels were rapidly formed by mixing the polymer solutions containing horseradish peroxidase (HRP) and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>). The ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5639002 Sat, 21 Jan 2012 05:00:00 +0100 5639002 http://www.medworm.com/index.php?rid=5639001&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22263698%26dopt%3DAbstract Authors: Hoffmann S, Vystrčilová L, Ulbrich K, Etrych T, Caysa H, Mueller T, Mäder K Abstract Preclinical in vivo characterisation of new polymeric drug conjugate candidates is crucial to understand the effects of certain chemical modifications on distribution and elimination of these carrier systems, which is the basis for rational drug design. In our study we synthesised dual fluorescent HPMA copolymers of different architecture and molecular weight, containing one fluorescent dye coupled via a stable hydrazide bond functioning as the carrier label and the other one modelling the drug bound to a carrier via a pH-sensitive hydrolytically cleavable hydrazone bond. Thus it was possible to track the in vivo fate (distribution, elimination and tumour accumulation) of the polymer dr... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5639001 Sat, 21 Jan 2012 05:00:00 +0100 5639001 http://www.medworm.com/index.php?rid=5639004&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22263611%26dopt%3DAbstract Authors: Kittle JD, Wang C, Qian C, Zhang Y, Zhang M, Roman M, Morris JR, Moore RB, Esker AR Abstract Chitin is the second most abundant biopolymer and insight into its natural synthesis, enzymatic degradation, and chemical interactions with other biopolymers is important for bioengineering with this renewable resource. This work is the first report of smooth, homogeneous, ultrathin chitin films, opening the door to surface studies of binding interactions, adsorption kinetics, and enzymatic degradation. The chitin films were formed by spincoating trimethylsilyl chitin onto gold or silica substrates, followed by regeneration to a chitin film. Infrared and x-ray photoelectron spectroscopy, x-ray diffraction, ellipsometry, and atomic force microscopy were used to confirm the formation... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5639004 Fri, 20 Jan 2012 05:00:00 +0100 5639004 http://www.medworm.com/index.php?rid=5620872&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22260431%26dopt%3DAbstract Authors: Sèbe G, Ham-Pichavant F, Ibarboure E, Koffi AL, Tingaut P Abstract Cellulose II nanowhiskers (CNW-II) were produced by treatment of microcrystalline cellulose with sulfuric acid by both controlling the amount of H2SO4 introduced and the time of addition during the hydrolysis process. The crystalline structure was confirmed by both XRD and 13C CP-MAS NMR spectroscopy. When observed between crossed polarizers, the cellulose II suspension displayed flow birefringence and was stable for several months. The CNW-II nanowhiskers were significantly smaller than the cellulose I nanowhiskers (CNW-I) and had a rounded shape at the tip. The CNW-II average length and height were estimated by AFM to be 153 ± 66 nm and 4.2 ± 1.5 nm, respectively. An average width of 6.3 ± 1.7 nm was ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620872 Fri, 20 Jan 2012 05:00:00 +0100 5620872 http://www.medworm.com/index.php?rid=5620876&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22251371%26dopt%3DAbstract Authors: Qi ZD, Saito T, Fan Y, Isogai A Abstract An environmentally benign surface modification process for plastic films was demonstrated by fabricating composite coatings through layer-by-layer assembly with green solid materials: aqueous dispersions of two kinds of crystalline polysaccharide nanofibrils. Anionic cellulose nanofibrils were obtained by the TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation of native cellulose, while cationic β-chitin nanofibrils were prepared by the protonation of squid pen chitin. Uniform layer depositions, driven by electrostatic attraction and enhanced by hydrogen bonding, were observed on silicon wafers and then reproduced onto poly(ethylene terephthalate) films. Contact angle measurements and dyeing tests on the resulti... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620876 Wed, 18 Jan 2012 05:00:00 +0100 5620876 http://www.medworm.com/index.php?rid=5620875&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22257019%26dopt%3DAbstract Generic Method for Modular Surface Modification of Cellulosic Materials in Aqueous Medium by Sequential "Click"-Reaction and Adsorption. Biomacromolecules. 2012 Jan 18; Authors: Filpponen I, Kontturi E, Nummelin S, Rosilo H, Kolehmainen E, Ikkala O, Laine J Abstract A generic approach for heterogeneous surface modification of cellulosic materials in aqueous medium, applicable for a wide range of functionalizations, is presented. In the first step, carboxymethyl cellulose (CMC) modified with azide or alkyne functionality, was adsorbed on a cellulosic substrate, thus providing reactive sites for azide-alkyne cycloaddition click reactions. In the second step, functional units with complementary click units were reacted on the cellulose surface, coated by the click-modified CMC... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620875 Wed, 18 Jan 2012 05:00:00 +0100 5620875 http://www.medworm.com/index.php?rid=5620874&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22257068%26dopt%3DAbstract Authors: Wang J, Yiu B, Obermeyer J, Filipe CD, Brennan JD, Pelton R Abstract The stability of a paper-immobilized antibody was investigated over a range of temperature (40 - 140 °C) and relative humidity (RH, 30 - 90%) using both unmodified filter paper and the same paper impregnated with polyamide-epichlorohydrin (PAE) as supports. Antibody stability decreased with increasing temperature, as expected, but also decreased with increasing RH. At 40 °C the half-life was more than ten days, with little dependence on RH. However at 80 °C, the half-life varied from ~3 days at low RH to less than half an hour at 90% RH, demonstrating that hydration of the antibody promotes unfolding. Antibody stability was not influenced by the PAE paper surface treatment. This work shows that antibod... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620874 Wed, 18 Jan 2012 05:00:00 +0100 5620874 http://www.medworm.com/index.php?rid=5620883&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22229781%26dopt%3DAbstract Authors: Xu D, Edgar KJ Abstract Tetrabutylammonium fluoride has been found to catalyze the deacylation of cellulose esters. More surprisingly, the deacylation is highly regioselective. Even more remarkably, in contrast with the C-6 regioselectivity of other reactions of cellulose and its derivatives, this deacylation shows substantial selectivity for the removal of the acyl groups from the esters of the secondary alcohols at C-2 and C-3, affording cellulose-6-O-esters with high regioselectivity by a simple one-step process employing no protective groups. PMID: 22229781 [PubMed - as supplied by publisher] (Source: Biomacromolecules) Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620883 Tue, 17 Jan 2012 05:00:00 +0100 5620883 http://www.medworm.com/index.php?rid=5620879&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22248303%26dopt%3DAbstract Authors: Arola SA, Tammelin T, Setälä H, Tullila A, Linder MB Abstract In a number of different applications for enzymes and specific binding proteins a key technology is the immobilization of these proteins to different types of supports. In this work we describe a concept for protein immobilization that is based on nanofibrillated cellulose (NFC). NFC is a form of cellulose where fibers have been disintegrated into fibrils that are only a few nanometers in diameter and have a very large aspect ratio. Proteins were conjugated through three different strategies using amine, epoxy, and carboxylic acid functionalized NFC. The conjugation chemistries were chosen according to the reactive groups on the NFC derivatives; epoxy amination, heterobifunctional modification of amino groups,... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620879 Tue, 17 Jan 2012 05:00:00 +0100 5620879 http://www.medworm.com/index.php?rid=5620878&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22251248%26dopt%3DAbstract We present a novel photo-polymerizable poly(L-lysine) (PLL) and use it to modify polyethylene glycol diacrylate (PEGDA) hydrogels for creating a better, permissive nerve cell niche. Compared with their neutral counterparts, these PLL-grafted hydrogels greatly enhance pheochromocytoma (PC12) cell survival in encapsulation, proliferation, and neurite growth, and also promote neural progenitor cell proliferation and differentiation capacity, represented by percentages of both differentiated neurons and astrocytes. The role of efficiently controlled substrate stiffness in regulating nerve cell behavior is also investigated and a polymerizable cationic small molecule, [2-(methacryloyloxy)ethyl]-trimethylammonium chloride (MTAC), is used to compare with this newly developed PLL. The results indi... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620878 Tue, 17 Jan 2012 05:00:00 +0100 5620878 http://www.medworm.com/index.php?rid=5620877&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22251304%26dopt%3DAbstract Authors: Patenaude M, Hoare T Abstract A series of synthetic oligomers (based on the thermosensitive polymer poly(N-isopropylacrylamide) and carbohydrate polymers (including hyaluronic acid, carboxymethyl cellulose, dextran, and methylcellulose) were functionalized with hydrazide or aldehyde functional groups and mixed using a double-barreled syringe to create in situ-gelling, hydrazone-crosslinked hydrogels. By mixing any number and any ratio of different reactive oligomer or polymer precursors, hydrogels with defined swelling, degradation, phase transition, drug binding, and mechanical properties were produced. Using this modular, mixing approach, one property can be selectively modified while keeping other properties constant, providing a highly adaptable method of engineering i... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620877 Tue, 17 Jan 2012 05:00:00 +0100 5620877 http://www.medworm.com/index.php?rid=5620880&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22242897%26dopt%3DAbstract In this study, we investigated the structure-function effects of conjugating various hydrophobic biocompatible side chains to poly(glycerol-co-caprolactone) copolymers with the goal of achieving prolonged and controlled release of a chemotherapeutic agent. The choice of side chain significantly affected the resulting polymer properties including thermal transitions, relative crystallinity (ΔHf), and hydrophobicity. Drug-loaded films cast from solutions of polymer and 10-hydroxycamptothecin demonstrated prolonged release from four to over seven weeks depending upon side chain structure without initial burst release behavior. Use of the stearic acid-conjugated poly(glycerol-co-caprolactone) films afforded substantial anti-cancer activity in vitro for at least 50 days when exposed to fresh c... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620880 Sun, 15 Jan 2012 05:00:00 +0100 5620880 http://www.medworm.com/index.php?rid=5620881&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22239547%26dopt%3DAbstract Authors: Kondo M, Iida K, Dewa T, Tanaka H, Ogawa T, Nagashima S, Nagashima KV, Shimada K, Hashimoto H, Gardiner AT, Cogdell RJ, Nango M Abstract A poly-histidine (His) tag was fused to the C- or N-terminus of the light-harvesting (LH1)-αchain of the photosynthetic antenna core complex (LH1-RC) from Rhodobacter sphaeroides to allow immobilization of the complex on a solid substrate with defined orientation. His-tagged LH1-RCs were adsorbed onto a gold electrode modified with Ni-NTA. The LH1-RC with the C-terminal His-tag (C-His LH1-RC) on the modified electrode produced a photovoltaic response upon illumination. Electron transfer is unidirectional within the RC, and starts when the bacteriochlorophyll a dimer in the RC is activated by light absorbed by LH1. The LH1-RC with t... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620881 Thu, 12 Jan 2012 05:00:00 +0100 5620881 http://www.medworm.com/index.php?rid=5620882&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22235992%26dopt%3DAbstract Authors: Wintgens V, Layre AM, Hourdet D, Amiel C Abstract The main goal of this work was to develop two strategies for stabilization of nanoassemblies made of ß-cyclodextrin polymer and amphiphilic dextran associated through host-guest complexes. The first strategy was to coat the nanoassemblies with a dextran derivative bearing adamantyl anchoring groups and hydrophilic poly(ethylene oxide-co-propylene oxide) side chains in order to increase the steric repulsion between the nanoassemblies. The second strategy developed was to post reticulate the nanoassemblies upon UV irradiation. Photo-crosslinkable nanoassemblies have been prepared from new host or guest polymers bearing allylether or methacrylate groups. The modified nanoassemblies have been characterized by dynamic light sca... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620882 Wed, 11 Jan 2012 05:00:00 +0100 5620882 http://www.medworm.com/index.php?rid=5620885&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22229696%26dopt%3DAbstract Authors: Canabady-Rochelle LL, Belton DJ, Deschaume O, Currie HA, Kaplan DL, Perry CC Abstract Novel protein chimeras constituted of 'silk' and a silica-binding peptide (KSLSRHDHIHHH) were synthesized by genetic or chemical approaches and their influence on silica-silk based chimera composite formation evaluated. Genetic chimeras were constructed from 6 or 15 repeats of the 32 amino acid consensus sequence of Nephila clavipes spider silk ([SGRGGLGGQG AGAAAAAGGA GQGGYGGLGSQG]n) to which one silica binding peptide was fused at the N terminus. For the chemical chimera, 25 equivalents of the silica binding peptide were chemically coupled to natural Bombyx mori silk after modification of tyrosine groups by diazonium coupling and EDC/NHS activation of all acid groups. After silica format... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620885 Tue, 10 Jan 2012 05:00:00 +0100 5620885 http://www.medworm.com/index.php?rid=5620890&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22229467%26dopt%3DAbstract In this study, we prepared a series of targeted cationic lipoplex based on two synthetic lipid components, mannose-poly(ethylene glycol, MW3000)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (Mannose-PEG3000-DSPE) and O-(2R-1,2-di-O-(1'Z,9'Z-octadecadienyl)-glycerol)-3-N-(bis-2-aminoethyl)-carbamate (BCAT), that were formulated with 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) for evaluation as nonviral vectors for transgene expression in DCs. First, we optimized the N/P ratio for maximum transfection and then screened the effects of mannose targeting for further enhancement of transfection levels. Our results indicate that efficient delivery of gWIZ GFP plasmid into DCs was observed for mannose compositions of ∼10%, whereas low transfection efficiencies were observed with nont... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620890 Mon, 09 Jan 2012 05:00:00 +0100 5620890 http://www.medworm.com/index.php?rid=5620889&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22229499%26dopt%3DAbstract Authors: Svagan AJ, Akesson A, Cárdenas M, Bulut S, Knudsen JC, Risbo J, Plackett D Abstract Polylactide (PLA) is viewed as a potential material to replace synthetic plastics (e.g., poly(ethylene terephthalate) (PET)) in food packaging, and there have been a number of developments in this direction. However, for PLA to be competitive in more demanding uses such as the packaging of oxygen-sensitive foods, the oxygen permeability coefficient (OP) needs to be reduced by a factor of ∼10. To achieve this, a layer-by-layer (Lbl) approach was used to assemble alternating layers of montmorillonite clay and chitosan on extruded PLA film surfaces. When 70 bilayers were applied, the OP was reduced by 99 and 96%, respectively, at 20 and 50% RH. These are, to our knowledge, the best improvem... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620889 Mon, 09 Jan 2012 05:00:00 +0100 5620889 http://www.medworm.com/index.php?rid=5620888&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22229537%26dopt%3DAbstract Authors: Tripisciano C, Leistner A, Linsberger I, Leistner A, Falkenhagen D, Weber V Abstract In liver failure, hydrophobic toxins accumulate in the blood circulation. To support hepatic function, extracorporeal blood purification systems have been developed, in which both cationic and neutral adsorbents are used to remove albumin-bound metabolites from blood. An issue of these systems is the additional removal of coagulation factors containing negatively charged γ-carboxyglutamate (Gla) domains, which, under physiological conditions, are shielded by calcium ions. We hypothesized that complexation of calcium ions by citrate leads to exposure of negative Gla domains, resulting in their binding to positively charged adsorbents. The data presented here confirm that the binding of coa... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620888 Mon, 09 Jan 2012 05:00:00 +0100 5620888 http://www.medworm.com/index.php?rid=5620887&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22229633%26dopt%3DAbstract Authors: Pakravan M, Heuzey MC, Ajji A Abstract Core-shell structured PEO-chitosan nanofibers have been produced using a co-axial electrospinning set-up. PEO and chitosan solutions, both in an aqueous acetic acid solvent, were used as the inner (core) and outer (shell) layer, respectively. Uniform sized defect-free nanofibers of 150-190 nm diameter were produced. In addition, hollow nanofibers could be obtained subsequent to PEO washing of the membranes. The core-shell nanostructure and existence of chitosan on the shell layer were confirmed by TEM images obtained before and after washing the PEO content with water. The presence of chitosan on the surface of the composite nanofibers was further supported by XPS studies. The chitosan and PEO compositions in the nanofibrous mats were... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620887 Mon, 09 Jan 2012 05:00:00 +0100 5620887 http://www.medworm.com/index.php?rid=5620886&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22229657%26dopt%3DAbstract We report on the kinetics and extent of adsorption on silica and cellulose surfaces of glycinin and β-conglycinin, the main proteins present in soy. Quartz crystal microgravimetry experiments indicate that soy protein adsorption is strongly affected by changes in the physicochemical environment. The affinity of glycinin and the mass adsorbed on silica and cellulose increases (by ca. 13 and 89 %, respectively) with solution ionic strength (as it increases from 0 to 100 mM NaCl) due to screening of electrostatic interactions. In contrast, β-conglycinin adsorbs on the same substrates to a lower extent and the addition of electrolyte reduces adsorption (by 25 and 57 %, respectively). The addition of 10 mM 2-mercaptoethanol, a denaturing agent, reduces the adsorption of both proteins with a s... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620886 Mon, 09 Jan 2012 05:00:00 +0100 5620886 http://www.medworm.com/index.php?rid=5620884&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22229738%26dopt%3DAbstract One-step "click" method for generating vinyl sulfone groups on hydroxyl-containing water soluble polymers. Biomacromolecules. 2012 Jan 9; Authors: Yu Y, Chau Y Abstract A one-step "click" method for generating vinyl sulfone groups on hydroxyl-containing water soluble polymer is presented. The reaction is simple, efficient, free of organic solvent, and is applicable to hyaluronic acid (HA), polyethylene glycol (PEG), dextran, alginate and polyvinyl alcohol (PVA). The degree of modification of the polymers can be easily controlled over a wide range. The vinyl sulfone grafted on the polymers can participate in thiol-Michael "click" reaction at physiological pH and temperature with thiol counterparts, which makes the modified polymers promising precursors for preparing in situ ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5620884 Mon, 09 Jan 2012 05:00:00 +0100 5620884 http://www.medworm.com/index.php?rid=5578004&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22224541%26dopt%3DAbstract Authors: Bechler SL, Lynn DM Abstract Polyelectrolyte multilayers (PEMs) fabricated from cationic polymers and DNA have been investigated broadly as materials for surface-mediated DNA delivery. One attractive aspect of this "multilayered" approach is the potential to exploit the presence of cationic polymer "layers" in these films to deliver DNA to cells more effectively. Past studies demonstrate that these films can promote transgene expression in vitro and in vivo, but significant questions remain regarding roles that the cationic polymers could play in promoting the internalization and processing of DNA. Here, we report physicochemical and in vitro cell-based characterization of DNA-containing PEMs fabricated using fluorescently end-labeled derivatives of a degradable polycation... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5578004 Fri, 06 Jan 2012 05:00:00 +0100 5578004 http://www.medworm.com/index.php?rid=5578005&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22220942%26dopt%3DAbstract This study is focused on the chromatographic characterization of lignocellulose from agricultural residues (rice husk, wheat straw) and herbaceous energy crops (Arundo donax, Miscanthus sinesis) and their fractionation products (hemicellulose, cellulose and lignin). Exploiting alternative chemical derivatizations on the aforementioned samples, it was possible to discern the connectivity among the various lignocellulosic components. The complete acetylation and benzoylation of the milled native substrates in ionic liquid media, and the systematic comparison between their GPC-UV chromatogram collected at different wavelengths has revealed itself as a straightforward technique in the detection of LCCs. This novel approach proved an extensive connectivity between the lignin and hemicellulosic ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5578005 Thu, 05 Jan 2012 05:00:00 +0100 5578005 http://www.medworm.com/index.php?rid=5559923&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22211695%26dopt%3DAbstract Water-stable all-biodegradable microparticles in nanofibers by electrospinning of aqueous dispersions for biotechnical plant protection. Biomacromolecules. 2012 Jan 3; Authors: Bansal P, Bubel K, Agarwal S, Greiner A Abstract ABSTRACT: Pheromone eluting oligolactide (OLA) microcapsules immobilized in electrospun biodegradable polyester nanofibers were obtained by electrospinning of aqueous dispersions of the microcapsules. OLA was prepared by conventional melt polycondensation of lactic acid. Following the protocol of the solvent displacement method OLA was dissolved in acetone and mixed with Brij® S20, and the pheromone of the European Grape vine Moth, Lobesia Botrana, (E,Z)-7,9-dodecadien-l-yl acetate (DA). Up to 32 wt% of this mixture could be dispersed in water with co... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5559923 Tue, 03 Jan 2012 05:00:00 +0100 5559923 http://www.medworm.com/index.php?rid=5559924&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22208863%26dopt%3DAbstract Authors: Ye X, Jiang X, Yu B, Yin J, Vana P Abstract A binary micropattern of anthracene-contained hyperbranched poly(ether amine) (hPEA-AN) hydrogel and poly(ether amine) (PEA) brush on gold surface was developed and explored. First, a micropatterned hPEA-AN hydrogel array on gold surface was fabricated by photolithography via photodimerization of anthracene moieties, and a PEA brush was subsequently immobilized on the remaining free gold surface areas by chemical-adsorption of thiol groups. The patterned hPEA-AN hydrogel exhibits selectivity with respect to the absorption of hydrophilic dyes: Methyl Orange (MO) is strongly absorbed but Rhodamine 6G (R6G) is not, as indicated by the fluorescence response. The PEA brush domain exhibits excellent protein adsorption repellency, while... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5559924 Fri, 30 Dec 2011 05:00:00 +0100 5559924 http://www.medworm.com/index.php?rid=5559925&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22206477%26dopt%3DAbstract We present a method of tuning surface chemistry and nerve cell behavior by photo-crosslinking methoxy poly(ethylene glycol) monoacrylate (mPEGA) with hydrophobic, semi-crystalline poly(ε-caprolactone) diacrylate (PCLDA), at various weight compositions of mPEGA (φ<sub>m</sub>) from 2 to 30%. Improved surface wettability is achieved with corresponding decreases in friction, water contact angle, and capability of adsorbing proteins from cell culture media because of repulsive PEG chains tethered in the network. The responses of rat Schwann cell precursor line (SpL201), rat pheochromocytoma (PC12), and E14 mouse neural progenitor cells (NPCs) to the modified surfaces are evaluated. Non-monotonic or parabolic dependence of cell attachment, spreading, proliferation, and differentia... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5559925 Thu, 29 Dec 2011 05:00:00 +0100 5559925 http://www.medworm.com/index.php?rid=5548930&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22191330%26dopt%3DAbstract Authors: Grotzky A, Manaka Y, Kojima T, Walde P PMID: 22191330 [PubMed - as supplied by publisher] (Source: Biomacromolecules) Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5548930 Thu, 22 Dec 2011 05:00:00 +0100 5548930 http://www.medworm.com/index.php?rid=5548929&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22191428%26dopt%3DAbstract Authors: Witte AB, Timmer CM, Gam JJ, Choi SK, Banaszak Holl MM, Orr BG, Baker JR, Sinniah K Abstract The present study describes the biophysical characterization of generation 5 poly(amidoamine) (PAMAM) dendrimers conjugated with riboflavin (RF) as a cancer targeting platform. Two new series of dendrimers were designed, each presenting the riboflavin ligand attached at a different site (isoalloxazine at N-3, and D-ribose at N-10) and at varying ligand valency. Isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC) were used to determine the binding activity for riboflavin binding protein (RfBP) in a cell free solution. The ITC data shows dendrimer conjugates have K<sub>D</sub> values of ≥465 nM on a riboflavin basis, an affinity ~93-fold l... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5548929 Thu, 22 Dec 2011 05:00:00 +0100 5548929 http://www.medworm.com/index.php?rid=5548928&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22191470%26dopt%3DAbstract Authors: Zhang Y, Zheng M, Kissel TH, Agarwal S Abstract Water soluble, degradable polymers based on poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) with low cytotoxicity and good p-DNA transfection efficiency are highlighted in this article. To solve the non-degradability issue of PDMAEMA, new polymers based on DMAEMA and 5,6 benzo-2-methylene-1,3-dioxepane (BMDO) for gene transfection were synthesized. A poly(ethylene oxide) (PEO) azo-initiator was used as free-radical initiator. PEGylation was performed to improve water solubility and to reduce cytotoxicity of the polymers. The resulting polymers contain hydrolysable ester linkages in the backbone and were soluble in water even with very high amounts of ester linkages. These degradable copolymers showed significantly less to... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5548928 Thu, 22 Dec 2011 05:00:00 +0100 5548928 http://www.medworm.com/index.php?rid=5548927&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22191486%26dopt%3DAbstract Authors: Hoang B, Reilly RM, Allen C Abstract Intracellular trafficking of Auger electron emitting radionuclides to perinuclear and nuclear regions of cells is critical to realizing their full therapeutic potential. In the present study, block copolymer micelles (BCMs) were labeled with the Auger electron emitter indium-111 (111In) and loaded with the radiosensitizer methotrexate. HER2 specific antibodies (trastuzumab fab) and nuclear localization signal (NLS; CGYGPKKKRKVGG) peptides were conjugated to the surface of the BCMs to direct uptake in HER2 expressing cells and subsequent localization in the cell nucleus. Cell uptake and intracellular distribution of the multifunctional BCMs were evaluated in a panel of breast cancer cell lines with different levels of HER2 expression. I... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5548927 Thu, 22 Dec 2011 05:00:00 +0100 5548927 http://www.medworm.com/index.php?rid=5533604&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22188342%26dopt%3DAbstract Authors: Lee LA, Nguyen QL, Wu L, Horvath G, Nelson RS, Wang Q Abstract The ability of Tobacco mosaic virus (TMV) to tolerate various amino acid insertions near its carboxy terminus is well known. Typically these inserts are based on antigenic sequences for vaccine development with plant viruses as carriers. However, we determined that the structural symmetries and the size range of the viruses could also be modeled to mimic the extracellular matrix proteins by inserting cell-binding sequences to the virus coat protein. The extracellular matrix proteins play important roles in guiding cell adhesion, migration, proliferation and stem cell differentiation. Previous studies with TMV demonstrated that the native and phosphate-modified virus particles enhanced stem cell differentiation ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533604 Wed, 21 Dec 2011 05:00:00 +0100 5533604 http://www.medworm.com/index.php?rid=5533638&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22133316%26dopt%3DAbstract Authors: Lecorre D, Vahanian E, Dufresne A, Bras J Abstract Starch nanocrystals (SNCs) are crystalline platelets resulting from the acid hydrolysis of starch. A limiting factor for their more widespread use is their preparation duration. Therefore, this study investigates the possibility of developing an enzymatic pretreatment of starch to reduce the acid hydrolysis duration. A screening of three types of enzymes, namely, α-amylase, β-amylase, and glucoamylase, is proposed, and the latter was selected for a pretreatment. Compared with the regular kinetics of hydrolysis for preparing SNC, that of pretreated starch was much faster. The extent of hydrolysis normally reached in 24 h was obtained after only 6 h, and the regular final yield (15% after 5 days) was reached in 45 h. AFM a... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533638 Tue, 20 Dec 2011 05:00:00 +0100 5533638 http://www.medworm.com/index.php?rid=5533625&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22148591%26dopt%3DAbstract Authors: Zeng JB, He YS, Li SL, Wang YZ Abstract Chitin is the second most abundant semicrystalline polysaccharide. Like cellulose, the amorphous domains of chitin can also be removed under certain conditions such as acidolysis to give rise to crystallites in nanoscale, which are the so-called chitin nanocrystals or chitin whiskers (CHWs). CHW together with other organic nanoparticles such as cellulose whisker (CW) and starch nanocrystal show many advantages over traditional inorganic nanoparticles such as easy availability, nontoxicity, biodegradability, low density, and easy modification. They have been widely used as substitutes for inorganic nanoparticles in reinforcing polymer nanocomposites. The research and development of CHW related areas are much slower than those of CW. H... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533625 Tue, 20 Dec 2011 05:00:00 +0100 5533625 http://www.medworm.com/index.php?rid=5533605&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22185486%26dopt%3DAbstract Authors: Adhikari AS, Mekhdjian AH, Dunn AR Abstract Proteolytic degradation of fibrin, the major structural component in blood clots, is critical both during normal wound healing and in the treatment of ischemic stroke and myocardial infarction. Fibrin-containing clots experience substantial strain due to platelet contraction, fluid shear, and mechanical stress at the wound site. However, little is understood about how mechanical forces may influence fibrin dissolution. We used video microscopy to image strained fibrin clots as they were degraded by plasmin, a major fibrinolytic enzyme. Applied strain causes up to 10-fold reduction in the rate of fibrin degradation. Analysis of our data supports a quantitative model in which the decrease in fibrin proteolysis rates with strain ste... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533605 Tue, 20 Dec 2011 05:00:00 +0100 5533605 http://www.medworm.com/index.php?rid=5533629&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22148422%26dopt%3DAbstract Authors: Fik CP, Krumm C, Muennig C, Baur TI, Salz U, Bock T, Tiller JC Abstract Polyoxazolines with a biocidal quarternary ammonium end-group are potent biocides. Interestingly, the antimicrobial activity of the whole macromolecule is controlled by the nature of the group at the distal end. These nonreactive groups are usually introduced via the initiator. Here we present a study with a series of polymethyloxazolines with varying satellite groups introduced upon termination of the polymerization reaction. This allowed us to introduce a series of functional satellites, including hydroxy, primary amino, and double-bond-containing groups. The resulting telechelic polyoxazolines were explored regarding their antimicrobial activity and toxicity. It was found that the functional satelli... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533629 Mon, 19 Dec 2011 05:00:00 +0100 5533629 http://www.medworm.com/index.php?rid=5533613&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22181348%26dopt%3DAbstract Authors: Miserez A, Li Y, Cagnon J, Weaver JC, Waite HJ Abstract An elastic protein with a secondary structure distinct from all well-known load-bearing proteins is found in the byssus of the giant clam, Tridacna maxima. The byssus consists of a bundle of hundreds of individual threads, each measuring about about 100 μm in diameter, which exhibit a tendon-like mechanical response. The amino acid composition of Tridacna byssus, however, is unlike tendon collagen, lacking high glycine, proline and hydroxyproline. Wide-angle x-ray scattering (WAXS) and Small-Angle x-ray Scattering (SAXS) measurements suggest that the constituent nanofibrils of the byssal threads are distinct from known secondary structure motifs previously reported for elastic proteins including the collagen triple-h... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533613 Mon, 19 Dec 2011 05:00:00 +0100 5533613 http://www.medworm.com/index.php?rid=5533612&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22181561%26dopt%3DAbstract Modification of chitosan-methylcellulose composite films with <i>meso</i>-tetrakis(4-sulfonatophenyl)porphyrin. Biomacromolecules. 2011 Dec 19; Authors: Synytsya A, Grafova M, Slepicka P, Gedeon O, Synytsya A Abstract Polysaccharide films containing chitosan, methylcellulose, and a mixture of these polysaccharides in various ratios were prepared and modified with <i>meso</i>-tetrakis(4-sulfonatophenyl)porphyrin in an aqueous medium at pH 7. The modified films were compared with the initial films using spectroscopic methods and microscopic imaging. Electronic (UV-vis absorption, electronic circular dichroism, ECD) and vibrational (FTIR and Raman) spectra showed that the porphyrin macrocycles had a strong affinity toward chitosan and did not interact w... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533612 Mon, 19 Dec 2011 05:00:00 +0100 5533612 http://www.medworm.com/index.php?rid=5533606&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22181657%26dopt%3DAbstract Authors: Ibn Yaich A, Edlund UM, Albertsson AC Abstract Films and coatings were produced from a non-cellulosic polysaccharide rich wood hydrolysate (WH), and the resulting oxygen barrier performance was improved by a selective choice of upgrading conditions. The WH was obtained from process water in the hydrothermal treatment of hardwood and subjected to one of three alternative upgrading treatments, resulting in xylan rich fractions with significant differences in structure, composition and properties of the recovered WH fractions which in turn had a major impact on their performance with respect to tensile and oxygen barrier properties. The WH in the least upgraded state, the crudest fraction, produced films with the best performance in terms of oxygen permeability and was superi... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533606 Mon, 19 Dec 2011 05:00:00 +0100 5533606 http://www.medworm.com/index.php?rid=5533614&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22176525%26dopt%3DAbstract Authors: Sabaté R, Villar-Pique A, Espargaro A, Ventura S Abstract Fungal prions are protein-based genetic elements. Sup35 and Ure2p constitute the best-characterized prion proteins in the yeast Saccharomyces cerevisiae. No high-resolution molecular models of the amyloid conformations adopted by the prion domains of these proteins are available yet. A quantitative description of the kinetics and thermodynamics of their self-assembly processes might provide clues on the nature of the structural changes originating their heritable and transmissible phenotypes. Here we study the temperature dependence of Sup35 and Ure2p amyloid fibril nucleation and elongation reactions at physiological pH. Both processes follow the Arrhenius law, allowing calculation of their associated thermodynami... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533614 Sun, 18 Dec 2011 05:00:00 +0100 5533614 http://www.medworm.com/index.php?rid=5533617&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22176138%26dopt%3DAbstract Authors: Gnesa E, Hsia Y, Yarger JL, Weber W, Lin-Cereghino J, Lin-Cereghino GP, Tang S, Agari K, Vierra CA Abstract Spider silk is renowned for its extraordinary mechanical properties, having a balance of high tensile strength and extensibility. To date, the majority of studies have focused on the production of dragline silks from synthetic spider silk gene products. Here we report the first mechanical analysis of synthetic egg case silk fibers spun from the Latrodectus hesperus tubuliform silk proteins, TuSp1 and ECP-2. We provide evidence that recombinant ECP-2 proteins can be spun into fibers that display mechanical properties similar to other synthetic spider silks. We also demonstrate that silks spun from recombinant thioredoxin-TuSp1 fusion proteins which contain the conserv... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533617 Sat, 17 Dec 2011 05:00:00 +0100 5533617 http://www.medworm.com/index.php?rid=5533616&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22176209%26dopt%3DAbstract Authors: Le Brun AP, Chow JY, Bax DV, Nelson AR, Weiss AS, James M Abstract Tropoelastin is the precursor of the extracellular protein elastin and is utilized in tissue engineering and implant technology by adapting the interface presented by surface-bound tropoelastin. The preferred orientation of the surface bound protein is relevant to biointerface interactions, given the availability of the cell-binding C-terminus of tropoelastin. Using recombinant human tropoelastin we monitored the binding of tropoelastin on hydrophilic silica and on silica made hydrophobic by depositing a self-assembled monolayer of octadecyl trichlorosilane. The layered organization of deposited tropoelastin was probed using neutron and X-ray reflectometry both under aqueous conditions or dried. In a wet en... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533616 Sat, 17 Dec 2011 05:00:00 +0100 5533616 http://www.medworm.com/index.php?rid=5533615&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22176277%26dopt%3DAbstract Authors: Froehlich E, Mandeville JS, Arnold D, Kreplak L, Tajmir-Riahi HA Abstract Poly (ethylene glycol) (PEG) and its derivatives are synthetic polymers with major applications in gene and drug delivery systems. Synthetic polymers are also used to transport miRNA and siRNA in vitro. We studied the interaction of tRNA with several PEGs of different compositions, such as PEG 3350, PEG 6000 and mPEG-anthracene at physiological conditions. FTIR, UV-Visible, CD and fluorescence spectroscopic methods as well as atomic force microscopy (AFM) were used to analyse the PEG binding mode, the binding constant and the effects of polymer complexation on tRNA stability, aggregation and particle formation. Structural analysis showed that PEG-tRNA interaction occurs via RNA bases and the backb... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533615 Sat, 17 Dec 2011 05:00:00 +0100 5533615 http://www.medworm.com/index.php?rid=5533632&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22145672%26dopt%3DAbstract In this study, varying amounts of low molecular weight branched polyethylenimine 1.8 kDa (bPEI 1.8) were introduced on to a neutral polymer, poly(vinyl alcohol) (PVA), to bring in cationic charge on the resulting PVA-PEI (PP) nanocomposites. We rationalized that by introducing bPEI 1.8, buffering and condensation properties of the proposed nanocomposites would result in improved gene transfer capability. A series of PVA-PEI (PP) nanocomposites was synthesized using well-established epoxide chemistry and characterized by IR and NMR. Particle size of the PP/DNA complexes ranged between 120 to 135 nm, as determined by dynamic light scattering (DLS), and DNA retardation assay revealed efficient binding capability of PP nanocomposites to negatively charged nucleic acids. In vitro transfection o... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533632 Fri, 16 Dec 2011 05:00:00 +0100 5533632 http://www.medworm.com/index.php?rid=5533627&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22148512%26dopt%3DAbstract Biopolymers from Vegetable Oils via Catalyst- and Solvent-Free "Click" Chemistry: Effects of Cross-Linking Density. Biomacromolecules. 2011 Dec 16; Authors: Hong J, Luo Q, Wan X, Petrović ZS, Shah BK Abstract New monomers were prepared by introducing the azide groups in castor, canola, corn, soybean, and linseed oils. Polymerization of the azidated oils with alkynated soybean oil under thermal "click" chemistry conditions (without using a solvent or a catalyst) yielded fully cross-linked elastomers (1-5) of almost the same density (1.05 × 10(-3) kg/m(3)). The degree of cross-linking gradually increased from the castor-derived polymer (220 mol/m(3)) to the linseed-derived polymer (683 mol/m(3)). A systematic correlation between the degree of cross-linking and the thermal a... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533627 Fri, 16 Dec 2011 05:00:00 +0100 5533627 http://www.medworm.com/index.php?rid=5533626&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22148549%26dopt%3DAbstract We report here a mitochondria-targeted nanodelivery system for coenzyme Q10 (CoQ10) that can reach mitochondria and deliver CoQ10 in adequate quantities. Multifunctional nanocarriers based on ABC miktoarm polymers (A = poly(ethylene glycol (PEG), B = polycaprolactone (PCL), and C = triphenylphosphonium bromide (TPPBr)) were synthesized using a combination of click chemistry with ring-opening polymerization, self-assembled into nanosized micelles, and were employed for CoQ10 loading. Drug loading capacity (60 wt %), micelle size (25-60 nm), and stability were determined using a variety of techniques. The micelles had a small critical association concentration and were colloidally stable in solution for more than 3 months. The extraordinarily high CoQ10 loading capacity in the micelles is at... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533626 Fri, 16 Dec 2011 05:00:00 +0100 5533626 http://www.medworm.com/index.php?rid=5533618&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22176024%26dopt%3DAbstract Authors: Cheng J, Ji R, Gao S, Du F, Li ZC Abstract This work presents a facile approach for preparation of acid-labile and biocompatible polymers with pendent cyclic ortho esters, which is based on the efficient and mild reactions between cyclic ketene acetal (CKA) and hydroxyl groups. Three CKAs, 2-ethylidene-1,3-dioxane (EDO), 2-ethylidene-1,3-dioxolane (EDL), and 2-ethylidene-4- methyl-1,3-dioxolane (EMD) were prepared from the corresponding cyclic vinyl acetals by catalytic isomerization of the double bond. The reaction of CKAs with different alcohols and diols was examined using trace of p-toluenesulfonic acid as a catalyst. For the mono-hydroxyl alcohols, cyclic ortho esters were formed by simple addition of the hydroxyl group towards CKAs with ethanol showing a much greater... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533618 Fri, 16 Dec 2011 05:00:00 +0100 5533618 http://www.medworm.com/index.php?rid=5533620&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22168388%26dopt%3DAbstract Monodisperse, "highly" positively charged protein polymer drag-tags generated in an intein-mediated purification system used in free-solution electrophoretic separations of DNA. Biomacromolecules. 2011 Dec 15; Authors: Wang X, Albrecht JC, Lin JS, Barron AE Abstract Free-solution conjugate electrophoresis (FSCE) is a method of DNA sequencing that eliminates the need for viscous polymer solutions by tethering a carefully designed, mobility modifying "drag-tag" to each DNA molecule to achieve size-based separations of DNA. The most successful drag-tags to date are genetically engineered, highly repetitive polypeptides ("protein polymers") that are designed to be large, water-soluble, and completely monodisperse. Positively charged arginines were deliberately introduced at reg... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533620 Thu, 15 Dec 2011 05:00:00 +0100 5533620 http://www.medworm.com/index.php?rid=5533619&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22172250%26dopt%3DAbstract Authors: Agulhon P, Robitzer M, David L, Quignard F Abstract The morphologies of several ionotropic alginate hydrogels and aerogels were investigated by SAXS according to the nature of the divalent metal cation (Mn2+, Co2+, Zn2+, Cu2+ ) and the guluronic fraction of the alginate. All the alginate hydrogel and aerogel samples show isotropic small-angle X-ray scattering. Gelation results from cooperative associations of cations and chain segments and yields different nanostructures, i.e. nanofibrillar morphology or multiple junction morphology, according to cation type and eventually mannuronic/guluronic ratio. Thus, Mn and Cu gels present the same morphology whatever the guluronic ratio while Co and Zn gels yield different nanostructures. In the size range investigated by SAXS (~10-... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533619 Thu, 15 Dec 2011 05:00:00 +0100 5533619 http://www.medworm.com/index.php?rid=5533641&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22126590%26dopt%3DAbstract This study discusses this ability to stabilize oil-in-water emulsions for cellulose nanocrystals varying in crystalline allomorph, morphology, and hydrolysis processes related to the amphiphilic character of nonhydrophobized cellulose nanocrystal. PMID: 22126590 [PubMed - as supplied by publisher] (Source: Biomacromolecules) Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533641 Wed, 14 Dec 2011 05:00:00 +0100 5533641 http://www.medworm.com/index.php?rid=5533637&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22136323%26dopt%3DAbstract Authors: Paës G, Chabbert B Abstract Biomass from lignocellulose (LC) is a highly complex network of cellulose, hemicellulose, and lignin, which is considered to be a sustainable source of fuels, chemicals and materials. To achieve an environmental friendly and efficient LC upgrading, a better understanding of the LC architecture is necessary. We have devised some LC bioinspired model systems, based on arabinoxylan gels, in which mobility of dextrans and BSA grafted with FITC has been studied by FRAP. Our results indicate that the probes diffusion is more influenced by their hydrodynamic radius than by the gel mesh size. The addition of some cellulose nanocrystals (CNCs) decreases polymer chain mobility and has low effect on the probes diffusion, suggesting that the gels are bette... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533637 Wed, 14 Dec 2011 05:00:00 +0100 5533637 http://www.medworm.com/index.php?rid=5533636&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22136353%26dopt%3DAbstract Authors: Zhang X, Guan Y, Zhang Y Abstract Novel biosensors have been designed by reporting an analyte-induced (de)swelling of a stimuli-responsive hydrogel (usually in a form of thin film) with a suitable optical transducer. These simple, inexpensive hydrogel biosensors are highly desirable, however, their practical applications have been hindered, largely because of their slow response. Here we show that quick response hydrogel sensors can be designed from ultrathin hydrogel films. By the adoption of layer-by-layer assembly, a simple but versatile approach, glucose-sensitive hydrogel films with thickness on submicrometer or micrometer scale, which is 2 orders of magnitude thinner than films used in ordinary hydrogel sensors, can be facilely fabricated. The hydrogel films can not ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533636 Wed, 14 Dec 2011 05:00:00 +0100 5533636 http://www.medworm.com/index.php?rid=5533622&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22168316%26dopt%3DAbstract Authors: Zhang J, Markiewicz MJ, Mowery BP, Weisblum B, Stahl SS, Gellman SH Abstract Nylon-3 polymers contain β-amino acid-derived subunits and can be viewed as higher homologues of poly(α-amino acids). This structural relationship raises the possibility that nylon-3 polymers offer a platform for development of new materials with a variety of biological activities, a prospect that has recently begun to receive experimental support. Nylon-3 homo- and copolymers can be prepared via anionic ring-opening polymerization of β-lactams, and use of an N-acyl-β-lactam as co-initiator in the polymerization reaction allows placement of a specific functional group, borne by the N-acyl-β-lactam, at the N-terminus of each polymer chain. Controlling the unit at the C-termini of nylon-3 polym... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533622 Wed, 14 Dec 2011 05:00:00 +0100 5533622 http://www.medworm.com/index.php?rid=5533621&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22168363%26dopt%3DAbstract Authors: Shi B, Shen Z, Zhang H, Bi J, Dai S Abstract Chitosan shows good biocompatibility and biodegradability, but the poor water solubility and low transfection efficiency hinder its applications as a gene delivery vector. We here report the detailed synthesis and characterization of a novel ampholytical chitosan derivative, N-imidazolyl-O-carboxymethyl chitosan (IOCMCS), used for high performance gene delivery. After chemical modification, the solubility of the resulting polymer is enhanced, and the polymer is soluble in a wide pH range (4 to 10). Gel electrophoresis study reveals the strong binding ability between plasmid DNA and the IOCMCS. Moreover, the IOCMCS does not induce remarkable cytotoxicity against human embryonic kidney (HEK293T) cells. The cell transfection result... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533621 Wed, 14 Dec 2011 05:00:00 +0100 5533621 http://www.medworm.com/index.php?rid=5533634&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22141318%26dopt%3DAbstract Authors: Ma H, Burger C, Hsiao BS, Chu B Abstract A multilayered nanofibrous microfiltration (MF) membrane system with high flux, low pressure drop, and high retention capability against both bacteria and bacteriophages (a virus model) was developed by impregnating ultrafine cellulose nanowhiskers (diameter about 5 nm) into an electrospun polyacrylonitrile (PAN) nanofibrous scaffold (fiber diameter about 150 nm) supported by a poly(ethylene terephthalate) (PET) nonwoven substrate (fiber diameter about 20 μm). The cellulose nanowhiskers were anchored on the PAN nanofiber surface, forming a cross-linked nanostructured mesh with very high surface-to-volume ratio and a negatively charged surface. The mean pore size and pore size distribution of this MF system could be adjusted by the ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533634 Tue, 13 Dec 2011 05:00:00 +0100 5533634 http://www.medworm.com/index.php?rid=5533624&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22148638%26dopt%3DAbstract Authors: Loh XJ, Del Barrio J, Toh PP, Lee TC, Jiao D, Rauwald U, Appel EA, Scherman OA Abstract The synthesis of a supramolecular double hydrophilic block copolymer (DHBC) held together by cucurbit[8]uril (CB[8]) ternary complexation and its subsequent self assembly into micelles is described. This system is responsive to multiple external triggers including temperature, pH and the addition of a competitive guest. The supramolecular block copolymer assembly consists of poly(N-isopropylacrylamide) (PNIPAAm) as a thermoresponsive block and poly(dimethylaminoethylmethacrylate) (PDMAEMA) as a pH-responsive block. Moreover, encapsulation and controlled drug release was demonstrated with this system using the chemotherapeutic drug doxorubicin (DOX). This triple stimuli-responsive DHBC m... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533624 Tue, 13 Dec 2011 05:00:00 +0100 5533624 http://www.medworm.com/index.php?rid=5533623&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22148683%26dopt%3DAbstract Authors: Jiravanichanun N, Yamamoto K, Kato K, Kim J, Horiuchi S, Yah WO, Otsuka H, Takahara A Abstract Imogolite is one of the clay minerals contained in volcanic ash soils. The novel hybrid hydrogels were prepared from imogolite nanofibers and DNA by utilizing strong interaction between the aluminol groups on imogolite surface and phosphate groups of DNA. The hybrid hydrogels of imogolite and DNA were prepared in various feed ratios, and their physicochemical properties and molecular aggregation states were investigated in both dispersion and gel states. The maximum DNA content in the hybrid gels was shown in equivalent molar ratio of imogolite and DNA. The physical properties of the hybrid gels were changed by varying DNA blend ratios. In the dispersion state, the hybrid gels sh... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533623 Tue, 13 Dec 2011 05:00:00 +0100 5533623 http://www.medworm.com/index.php?rid=5533635&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22136386%26dopt%3DAbstract Authors: Hemp ST, Allen MH, Green MD, Long TE Abstract Nonviral gene therapy focuses intensely on nitrogen-containing macromolecules and lipids to condense and deliver DNA as a therapeutic for genetic human diseases. For the first time, DNA binding and gene transfection experiments compared phosphonium-containing macromolecules with their respective ammonium analogs. Conventional free radical polymerization of quaternized 4-vinylbenzyl chloride monomers afforded phosphonium- and ammonium-containing homopolymers for gene transfection experiments of HeLa cells. Aqueous size exclusion chromatography confirmed similar absolute molecular weights for all polyelectrolytes. DNA gel shift assays and luciferase expression assays revealed phosphonium-containing polymers bound DNA at lower cha... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533635 Mon, 12 Dec 2011 05:00:00 +0100 5533635 http://www.medworm.com/index.php?rid=5533630&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22148348%26dopt%3DAbstract Authors: Aarstad OA, Tøndervik A, Sletta H, Skjåk-Bræk G Abstract Distribution and proportion of β-d-mannuronic and α-l-guluronic acid in alginates are important for understanding the chemical-physical properties of the polymer. The present state of art methods, which is based on NMR, provides a statistical description of alginates. In this work, a method was developed that also gives information of the distribution of block lengths of each of the three block types (M, G, and MG blocks). This was achieved using a combination of alginate lyases with different substrate specificities, including a novel lyase that specifically cleaves diguluronic acid linkages. Reaction products and isolated fragments of alginates degraded with these lyases were subsequently analyzed with (1)H NM... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533630 Mon, 12 Dec 2011 05:00:00 +0100 5533630 http://www.medworm.com/index.php?rid=5533644&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22112204%26dopt%3DAbstract Authors: Wang L, Prozorov T, Palo PE, Liu X, Vaknin D, Prozorov R, Mallapragada S, Nilsen-Hamilton M Abstract Highly ordered mineralized structures created by living organisms are often hierarchical in structure with fundamental structural elements at nanometer scales. Proteins have been found responsible for forming many of these structures, but the mechanisms by which these biomineralization proteins function are generally poorly understood. To better understand its role in biomineralization, the magnetotactic bacterial protein, Mms6, which promotes the formation in vitro of superparamagnetic magnetite nanoparticles of uniform size and shape, was studied for its structure and function. Mms6 is shown to have two phases of iron binding: one high affinity and stoichiometric and the ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533644 Fri, 09 Dec 2011 05:00:00 +0100 5533644 http://www.medworm.com/index.php?rid=5533628&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22148461%26dopt%3DAbstract Design of functionalized cellulosic honeycomb films - Site-specific biomolecule modification via "Click Chemistry" Biomacromolecules. 2011 Dec 8; Authors: Xu WZ, Zhang X, Kadla JF Abstract Value-added materials from naturally abundant polymers such as cellulose are of significant importance. In particular, cellulosic open-framework structures with controlled chemical functionality of the internal surface have great potential in many biosensor applications. Although various cellulose derivatives can form porous honeycomb structured materials, solubility issues and problems with film formation exist. To address this we have generated robust cellulosic open-framework structures which can be post functionalized through site-specific modification. Regioselectively modified amphi... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533628 Thu, 08 Dec 2011 05:00:00 +0100 5533628 http://www.medworm.com/index.php?rid=5533646&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22107030%26dopt%3DAbstract Authors: Furusawa K, Sato S, Masumoto JI, Hanazaki Y, Maki Y, Dobashi T, Yamamoto T, Fukui A, Sasaki N Abstract We have found that dialysis of 5 mg/mL collagen solution into the phosphate solution with a pH of 7.1 and an ionic strength of 256 mM at 25 °C results in a collagen gel with a birefringence and tubular pores aligned parallel to the growth direction of the gel. The time course of averaged diameter of tubular pores during the anisotropic gelation was expressed by a power law with an exponent of 1/3, suggesting that the formation of tubular pores is attributed to a spinodal decomposition-like phase separation. Small angle light scattering patterns and high resolution confocal laser scanning microscope images of the anisotropic collagen gel suggested that the collagen fibril... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533646 Wed, 07 Dec 2011 05:00:00 +0100 5533646 http://www.medworm.com/index.php?rid=5533631&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22145696%26dopt%3DAbstract Authors: Sawada D, Nishiyama Y, Langan P, Forsyth T, Kimura S, Wada M Abstract The hydrogen bonding arrangement in anhydrous β-chitin, a homopolymer of N-acetylglucosamine, was directly determined by neutron fiber diffraction. Data were collected from a sample prepared from the bathophilous tubeworm Lamellibrachia satsuma in which all labile hydrogen atoms had been replaced by deuterium. Initial positions of deuterium atoms on hydroxyl and acetamide groups were directly located in Fourier maps synthesized using phases calculated from the X-ray structure and amplitudes measured from the neutron data. The hydrogen bond arrangement in the refined structure is in general agreement with predictions based on the X-ray structure; O3 donates a hydrogen bond to the O5 ring oxygen atom of a... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533631 Wed, 07 Dec 2011 05:00:00 +0100 5533631 http://www.medworm.com/index.php?rid=5533645&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22107051%26dopt%3DAbstract Authors: Rao N V, Mane S, Kishore A, Das Sarma J, Shunmugam R Abstract The synthesis and complete characterization of both norbornene-derived doxorubicin (mono 1) and polyethylene glycol (mono 2) monomers are clearly described, and their copolymerization by ring-opening metathesis polymerization (ROMP) to get the block copolymer (COPY-DOX) is vividly elaborated. The careful design of these conjugates exhibits properties like well-shielded drug moieties and well-defined nanostructures; additionally, they show solubility in both water and biological medium and also have the important tendency of rendering acid-triggered drug release. The drug release profile suggests the importance of having the hydrazone linker that helps to release the drug exactly at the mild acidic conditions res... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533645 Tue, 06 Dec 2011 05:00:00 +0100 5533645 http://www.medworm.com/index.php?rid=5533642&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22122562%26dopt%3DAbstract In this study, the terminal carboxylation of PIPAAm chains provided high cell adhesive property to thermoresponsive surfaces. Although cell adhesion is generally promoted by a decrease in the grafted PIPAAm amount, the decrease also decelerated thermally-induced cell detachment, whereas the influence of terminal modification was negligible on the cell detachment. Consequently, the terminally modified PIPAAm brush surfaces allowed smooth muscle cells (SMCs) to simultaneously adhere strongly and detach themselves rapidly. In this study, SMCs were unable to reach a confluent monolayer on as-prepared PIPAAm brush surfaces (grafted amount: 0.41 μg/cm(2)) without terminal carboxylation due to their insufficient cell-adhesion strength. On the other hand, though a decrease in the PIPAAm amount al... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533642 Tue, 06 Dec 2011 05:00:00 +0100 5533642 http://www.medworm.com/index.php?rid=5533633&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22145634%26dopt%3DAbstract In conclusion, the ECE hydrogel has a temperature-sensitive sol-gel phase transition and is effective in vitro. Its intraocular biocompatibility demonstrated its great potential to be widely used in biomedical applications for extended drug release. PMID: 22145634 [PubMed - as supplied by publisher] (Source: Biomacromolecules) Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533633 Tue, 06 Dec 2011 05:00:00 +0100 5533633 http://www.medworm.com/index.php?rid=5533643&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22114903%26dopt%3DAbstract Authors: Milkova V, Kamburova K, Cameron R, Radeva T Abstract Complexation between ferric oxide particles and pectins with degree of methylation 50% but having ordered or random arrangement of free carboxyl groups is investigated by electric light scattering and electrophoresis. The influence of charge distribution in pectin chain on the electrical properties of oppositely charged oxide particles and stability of their suspensions is examined as a function of pectin concentration. Although the difference in charge density of pectin samples is ∼5%, we found small but measurable difference in the behavior of both oxide/pectin complexes. This is attributed to condensation of counterions near the chains of pectin with ordered distribution of charges, leading to a decrease in the effe... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533643 Thu, 01 Dec 2011 05:00:00 +0100 5533643 http://www.medworm.com/index.php?rid=5533640&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22133097%26dopt%3DAbstract Authors: Rosenthal EQ, Puskas JE, Wesdemiotis C Abstract This paper reports the synthesis and characterization of disulfide polymers obtained by oxidation of 2-[2-(2-sulfanylethoxy)ethoxy]ethanethiol (DODT) using a benign, synergistic system comprised of air, dilute hydrogen peroxide and triethylamine as a catalyst that can be recycled. The dn/dc value of the polymer in THF was determined to obtain absolute molecular weight measurements. High molecular weight disulfide polymers (up to M(n) = 250000 g/mol) with polydispersity indices as low as M(w)/M(n) = 1.15 were obtained. Thermal analysis by DSC and TGA demonstrated that the rubbery polymers had a T(g) of -50 °C and began to degrade at 250 °C. Dithiothreitol reduced the polymers back to the original monomeric units in 33 h. MAL... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533640 Thu, 01 Dec 2011 05:00:00 +0100 5533640 http://www.medworm.com/index.php?rid=5533639&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22133238%26dopt%3DAbstract In this study, densified collagen films (up to 100 μm thick) were fabricated by a plastic compression technique and cross-linked using carbodiimide. Then, collagen-hydroxyapatite composites were prepared by using a polymer-induced liquid-precursor (PILP) mineralization process. Compared to traditional methods that produce only extrafibrillar hydroxyapatite (HA) clusters on the surface of collagen scaffolds, by using the PILP mineralization process, homogeneous intra- and extrafibrillar minerals were achieved on densified collagen films, leading to a similar nanostructure as bone, and a woven microstructure analogous to woven bone. The role of collagen cross-links on mineralization was examined and it was found that the cross-linked collagen films stimulated the mineralization reaction, wh... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5533639 Thu, 01 Dec 2011 05:00:00 +0100 5533639 http://www.medworm.com/index.php?rid=5439860&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22103705%26dopt%3DAbstract Authors: Bulacu M, Periole X, Marrink SJ Abstract The robustness of microorganisms used in industrial fermentations is essential for the efficiency and yield of the production process. A viable tool to increase the robustness is through engineering of the cell membrane, and especially by incorporating lipids from species that survive under harsh conditions. Bolalipids are tetraether lipids found in Archaea bacteria conferring stability to these bacteria by spanning across the cytoplasmic membrane. Here we report on in-silico experiments to characterize and design optimal bolalipid membranes in terms of robustness. We use coarse-grained molecular dynamics simulations to study the structure, dynamics, and stability of membranes composed of model bolalipids, consisting of two dipalmit... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5439860 Mon, 21 Nov 2011 05:00:00 +0100 5439860 http://www.medworm.com/index.php?rid=5439861&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22098057%26dopt%3DAbstract Authors: Irague R, Rolland-Sabaté A, Tarquis L, Doublier JL, Moulis C, Monsan PF, Remaud-Simeon M, Potocki-Véronèse G, Buleon AJ Abstract Seven dextran types, displaying from 3 to 20% (1→3) glycosidic linkages, were synthesized in vitro from sucrose by mutants of dextransucrase DSR-S from Leuconostoc mesenteroides NRRL B-512F, obtained by combinatorial engineering. The structural and physico-chemical properties of these original biopolymers were characterized. Using asymmetrical flow field flow fractionation coupled with multiangle laser light scattering, it was determined that weight average molar masses and radii of gyration ranged from 0.76 to 6.02 x 108 g.mol-1 and from 55 to 206 nm, respectively. G values reveal that dextrans Gcn6 and Gcn7, which contain 15 and 20% ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5439861 Fri, 18 Nov 2011 05:00:00 +0100 5439861 http://www.medworm.com/index.php?rid=5419110&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22066528%26dopt%3DAbstract Authors: Raspanti M, Reguzzoni M, Protasoni M, Martini D Abstract The collagen fibrils of cornea, blood vessel walls, skin, gut, interstitial tissues, the sheath of tendons and nerves, and other connective tissues are known to be made of helically wound subfibrils winding at a constant angle to the fibril axis. A critical aspect of this model is that it requires the axial microfibrils to warp in an implausible way. This architecture lends itself quite naturally to an epitaxial layout where collagen microfibrils envelop a central core of a different nature. Here we demonstrate an axial domain in collagen fibrils from rabbit nerve sheath and tendon sheath by means of transmission electron microscopy after a histochemical reaction designed to evidence all polysaccharides and by tappin... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5419110 Wed, 16 Nov 2011 05:00:00 +0100 5419110 http://www.medworm.com/index.php?rid=5419107&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22070169%26dopt%3DAbstract Authors: Ahn SH, Lee HJ, Kim GH Abstract Electrohydrodynamic (EHD) direct writing has been used in diverse microelectromechanical systems and various supplemental methods for biotechnology and electronics. In this work, we expanded the use of EHD-induced direct writing to fabricate 3D biomedical scaffolds designed as porous structures for bone tissue engineering. To prepare the scaffolds, we modified a grounded target used in conventional EHD direct printing using a poly(ethylene oxide) solution bath, elastically cushioning the plotted struts to prevent crumbling. The fabricated scaffolds were assessed for not only physical properties including surface roughness and water uptake ability but also biological capabilities by culturing osteoblast-like cells (MG63) for the EHD-plotted p... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5419107 Wed, 16 Nov 2011 05:00:00 +0100 5419107 http://www.medworm.com/index.php?rid=5419105&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22077387%26dopt%3DAbstract Authors: Duan C, Gao J, Zhang D, Jia L, Liu Y, Zheng D, Liu G, Tian X, Wang F, Zhang Q Abstract Nanogels based on the polymers of galactosylated chitosan-graft-poly (N-isopropylacrylamide) (Gal-CS-g-PNIPAm) were used as carriers of oridonin (ORI) for tumor targeting. Three ORI-loaded nanogels with various degrees of galactose substitution were prepared, and their characteristics were evaluated. The release behavior of ORI from these nanogels was pH-dependent, and the release could be accelerated under mildly acidic conditions. The cytotoxicity of ORI-loaded nanogels was pH-sensitive. ORI-loaded nanogels exhibited a higher antitumor activity than drug-loaded nanogels without galactosylation, and the anticancer activity increased in relation to increases in the number of galactose mo... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5419105 Wed, 16 Nov 2011 05:00:00 +0100 5419105 http://www.medworm.com/index.php?rid=5419103&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22082257%26dopt%3DAbstract Authors: Ji W, Panus D, Palumbo RN, Tang R, Wang C Abstract Poly(2-aminoethyl methacrylate) (PAEM) homopolymers with defined chain length and narrow molecular weight distribution were synthesized using atom transfer radical polymerization (ATRP), and a comprehensive study was conducted to evaluate the colloidal properties of PAEM/plasmid DNA polyplexes, the uptake and subcellular trafficking of polyplexes in antigen-presenting dendritic cells (DCs), and the biological performance of PAEM as a potential DNA vaccine carrier. PAEM of different chain length (45, 75, and 150 repeating units) showed varying strength in condensing plasmid DNA into narrowly dispersed nanoparticles with very low cytotoxicity. Longer polymer chain length resulted in higher levels of overall cellular uptake a... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5419103 Wed, 16 Nov 2011 05:00:00 +0100 5419103 http://www.medworm.com/index.php?rid=5419104&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22077421%26dopt%3DAbstract In this study, copolymers of SBMA and acrylic acid (AA) with a variety of compositions were synthesized and were immobilized onto polymeric substrates with layer-by-layer polyelectrolyte films via electrostatic interaction. The amount of platelet adhesion and fibrinogen adsorption were determined to evaluate hemocompatibility of poly(SBMA-co-AA) modified substrates. Among various deposition conditions by modulating SBMA ratio in the copolymers and pH of the deposition solution, poly(SBMA56-co-AA44) deposited at pH 3.0 possessed the best hemocompatibility. This work demonstrated that poly(SBMA-co-AA) copolymers adsorbed on polyelectrolyte-base films via electrostatic interaction improve hemocompatibility effectively and are applicable for various substrates including TCPS, PU and PDMS. Furt... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5419104 Sun, 13 Nov 2011 05:00:00 +0100 5419104 http://www.medworm.com/index.php?rid=5419106&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22074384%26dopt%3DAbstract Authors: Prevost S, Riemer S, Fischer W, Haag R, Böttcher C, Gummel J, Grillo I, Appavou MS, Gradzielski M Abstract Polyplexes of short DNA-fragments (300~b.p., 100~nm) with tailor-made amine-based polycations of different architectures (linear and hyperbranched) were investigated in buffer solution as a function of the mixing ratio with DNA. The resulting dispersed polyplexes were characterized using small-angle neutron and X-ray scattering (SANS, SAXS) as well as cryo-TEM with respect to their mesoscopic structure and their colloidal stability. The linear polyimines form rather compact structures that have a high tendency for precipitation. In contrast, the hyperbranched polycation with enzymatic-labile pentaethylenehexamine arms (PEHA) yields polyplexes colloidally stable for m... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5419106 Thu, 10 Nov 2011 05:00:00 +0100 5419106 http://www.medworm.com/index.php?rid=5419109&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22066590%26dopt%3DAbstract Authors: Veiseh M, Breadner D, Ma J, Akentieva N, Savani RC, Harrison RE, Mikilus D, Collis L, Gustafson S, Lee TY, Koropatnick J, Luyt LG, Bissell MJ, Turley EA Abstract An increase in hyaluronan (HA) synthesis, cellular uptake and metabolism occurs during the remodeling of tissue microenvironments following injury and during disease processes such as cancer. We hypothesized that multi-modality HA-based probes selectively target to and detectably accumulate at sites of high HA metabolism thus providing a flexible imaging strategy for monitoring disease and repair processes. Kinetic analyses confirmed favorable available serum levels of the probe following intravenous (i.v.) or subcutaneous (s.c.) injection. Nuclear (technetium-HA, 99mTc-HA, and iodine-HA, 125I-HA), optical (fluore... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5419109 Wed, 09 Nov 2011 05:00:00 +0100 5419109 http://www.medworm.com/index.php?rid=5419108&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22066663%26dopt%3DAbstract Authors: Yan J, Korolev N, Eom KD, Tam JP, Nordenskiöld L Abstract Using solid phase synthesis, lysine can be oligomerized by a reaction of the peptide carboxylate with the ε-amino group to produce non-toxic, biodegradable cationic peptides, ε-oligo(L-lysines). Here, α-substituted derivatives of such ε-oligo(L-lysines), containing arginine and histidine in the side chain were tested as vectors for in vitro gene delivery. Combination of ε-oligolysines with the cationic lipid DOTAP and plasmid DNA resulted in transfection efficiency exceeding that of DOTAP alone, without significant increase in cytotoxicity. Synchrotron small angle X-ray scattering studies revealed self-assembly of the DOTAP, ε-oligolysines and DNA to ordered lamellar complexes. High transfection efficiency of... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5419108 Wed, 09 Nov 2011 05:00:00 +0100 5419108 http://www.medworm.com/index.php?rid=5419112&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22059927%26dopt%3DAbstract Authors: Brubaker CE, Messersmith PB Abstract Mussel-inspired adhesive hydrogels represent innovative candidate medical sealants or glues. In the present work, we describe an enzyme-degradable mussel-inspired adhesive hydrogel formulation, achieved by incorporating minimal elastase substrate peptide Ala-Ala into the branched poly(ethylene glycol) (PEG) macromonomer structure. The system takes advantage of neutrophil elastase expression upregulation and secretion from neutrophils upon recruitment to wounded or inflamed tissue. By integrating adhesive degradation behaviors that respond to cellular cues, we expand the functional range of our mussel-inspired adhesive hydrogel platforms. Rapid (<1 min) and simultaneous gelation and adhesion of the proteolytically-active, catechol-ter... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5419112 Mon, 07 Nov 2011 05:00:00 +0100 5419112 http://www.medworm.com/index.php?rid=5419111&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22059964%26dopt%3DAbstract Authors: Thielbeer F, Chankeshwara SV, Bradley M Abstract Fluorescent particles are used for a diverse number of biochemical assays including intracellular imaging, cellular tracking as well as detection of a variety of biomolecules. They are typically prepared by post-polymerization conjugations of dyes onto preformed particles. Herein, we report the synthesis of aminomethyl functionalized fluorescent particles via the synthesis and application of polymerizable fluorescein monomers. These monomers allowed high and controllable fluorophore loading into the particles resulting in enhanced fluorescence properties in comparison to more commonly used carboxyfluorescein conjugated particles. Furthermore, the particles were rapidly taken up by cells with enhanced fluorescence. The herein... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5419111 Mon, 07 Nov 2011 05:00:00 +0100 5419111 http://www.medworm.com/index.php?rid=5419113&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22053777%26dopt%3DAbstract Authors: Kow SC, McCarroll J, Valade D, Boyer CA, Dwarte T, Davis TP, Kavallaris M, Bulmus V Abstract Poly(ethylene glycol) (PEG) conjugates of Dicer-substrate small interfering RNA (DsiRNA) have been prepared to investigate a new siRNA delivery strategy. 3'-sense or 5'-antisense thiol modified, blunt-ended DsiRNAs, inhibiting enhanced green fluorescent protein (eGFP) expression, were covalently conjugated to PEG with varying molecular weights (2, 10 and 20 kg/mol) through a stable thioether bond using a Michael addition reaction. The DsiRNA conjugates with 2 kg/mol PEG (both 3'-sense or 5'-antisense strand conjugated) and the 10 kg/mol PEG conjugated to the 3'-sense strand of DsiRNA were efficiently cleaved by recombinant human Dicer to 21-mer siRNA, as determined by gel electroph... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5419113 Fri, 04 Nov 2011 04:00:00 +0100 5419113 http://www.medworm.com/index.php?rid=5379389&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22050053%26dopt%3DAbstract Authors: Hu X, Ji J Abstract A convenient and simple route to multifunctional surface coatings via the alternating covalent layer-by-layer (LBL) assembly of p-nitrophenyloxycarbonyl group-terminated hyperbranched polyether (HBPO-NO2) and polyethylenimine (PEI) was described. The in situ chemical reaction between HBPO-NO2 and PEI onto aminolyzed substrates was rapid and mild. Results from ellipsometry measurements, contact angle measurements and ATR-FTIR spectra confirmed the successful LBL assembly of the building blocks. And the surface reactivity of the multilayer films with HBPO-NO2 as the outmost layer was demonstrated by the immobilization of an amine-functionalized fluorophore. Further, a biomimetic surface was achieved by surface functionalization of the multilayer films wit... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5379389 Fri, 04 Nov 2011 04:00:00 +0100 5379389 http://www.medworm.com/index.php?rid=5379390&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22050007%26dopt%3DAbstract Authors: Ye C, Shchepelina O, Calabrese R, Drachuck I, Kaplan DL, Tsukruk VV Abstract We demonstrate the assembly of extremely robust and pH-responsive thin shell LbL microcapsules from silk fibroin counterparts modified with poly(lysine) and poly(glutamic) acid which are based on biocompatible silk ionomer materials in contrast to usually exploited synthetic polyelectrolytes. The microcapsules are extremely stable in the unusually wide pH range from 1.5 to 12.0 and show remarkable degree of reversible swelling/deswelling response in dimensions as exposed to extreme acidic and basic conditions. These changes are accompanied by reversible changes in shell permeability which can be utilized for pH-controlled loading and unloading of large macromolecules. Finally, we confirmed that th... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5379390 Thu, 03 Nov 2011 04:00:00 +0100 5379390 http://www.medworm.com/index.php?rid=5379391&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22047492%26dopt%3DAbstract Authors: Maglio G, Nicodemi F, Conte C, Palumbo R, Tirino P, Panza E, Ianaro A, Ungaro F, Quaglia F Abstract Well defined amphiphilic Y-shaped miktoarm star-block copolymers of PEO and PCL were synthesized by ring-opening polymerization of epsilon-caprolactone initiated by a PEO-bound lysine macroinitiator. The copolymers were characterized by 1H-NMR, SEC, DSC and WAXD techniques. Separate PCL and PEO crystalline phases occur in melt crystallized copolymers when their segmental lengths were comparable and the PCL content was around 80 wt%. Self-assembling of these copolymers in aqueous medium led to nanoaggregates with low critical aggregation concentration values (0.35-1.6 mg/L-1) and size depending on composition. Despite the copolymers were not prone to self-organize in vesicles... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5379391 Wed, 02 Nov 2011 04:00:00 +0100 5379391 http://www.medworm.com/index.php?rid=5379393&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22044242%26dopt%3DAbstract Authors: Ekemen Z, Chang H, Ahmad Z, Bayram C, Rong Z, Denkbas EB, Stride E, Vadgama P, Edirisinghe M Abstract In this work, we utilize a recently developed microbubbling process to generate controlled protein (bovine serum albumin, BSA) coated bubbles and then manipulate these to fabricate a variety of structures suitable for several generic biomedical applications, tissue engineering, and biosensor coatings. Using BSA solutions with varying concentrations (20, 25, and 30 wt %) and cross-linking (terephthaloyl chloride) mechanisms, structures were fabricated including porous thin films with variable pore sizes and thickness (partially cross-linked coupled to bubble breakdown), scaffolds with variable pore morphologies (fully cross-linked), and coated bubbles (no cross-linking), wh... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5379393 Tue, 01 Nov 2011 04:00:00 +0100 5379393 http://www.medworm.com/index.php?rid=5379392&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22044456%26dopt%3DAbstract Authors: Lv PP, Wei W, Yue H, Yang TY, Wang LY, Ma GH Abstract Clinical application of paclitaxel (PTX) is limited because of its poor solubility in aqueous media. To overcome this hurdle, we devised an oral delivery system by encapsulating PTX into N-((2-hydroxy-3-trimethylammonium) propyl) chitosan chloride (HTCC) nanoparticles. These nanoparticles were small (~130 nm), had a narrow size distribution, and displayed high loading efficiency owing to the homogenous distribution of PTX nanocrystals. The matrix hydrophilicity and porous structure of the obtained nanoparticles accelerated their degradation and improved drug release. In-vitro and in-vivo transport experiments had proved that the presence of positive charges enhanced the intestinal permeability of these nanoparticles. Fu... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5379392 Tue, 01 Nov 2011 04:00:00 +0100 5379392 http://www.medworm.com/index.php?rid=5379396&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22039998%26dopt%3DAbstract In this study, we investigated by atomic force microscopy the nanoscale organization of this interface for each individual step involved in the preparation of a bioactive interface: polymer adsorption, loading with streptavidin, and binding of biotinylated vesicles. PMID: 22039998 [PubMed - as supplied by publisher] (Source: Biomacromolecules) Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5379396 Mon, 31 Oct 2011 04:00:00 +0100 5379396 http://www.medworm.com/index.php?rid=5379395&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22040097%26dopt%3DAbstract This study investigated the temporal composition of an osteogenic extracellular matrix construct generated by culturing mesenchymal stem cells in an electrospun biodegradable poly(ε-caprolactone) fiber mesh scaffold within a flow perfusion bioreactor. Constructs of different extracellular matrix maturities were analyzed for their protein and mineral composition at several culture durations by liquid chromatography-tandem mass spectroscopy, scanning electron microscopy, energy dispersive x-ray diffraction, x-ray diffraction, and calcium and phosphate assays. The analysis revealed that at short culture durations the cells deposited cellular adhesion proteins as a prerequisite protein network for further bone formation. At the later culture durations, the extracellular matrix was composed of... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5379395 Mon, 31 Oct 2011 04:00:00 +0100 5379395 http://www.medworm.com/index.php?rid=5379394&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22040128%26dopt%3DAbstract Authors: Chen Y, Li X Abstract Polymeric near-infrared (NIR) fluorescent nanocapsules were developed, of which the fluorescence exhibited reversible response to local thermo/pH modulation. Our strategy was to use polymeric micelles made of temperature-sensitive Pluronic F-127 to encapsulate an amphiphilic NIR fluorescent dye-Indocyanine Green (ICG)-within the core and then cross-link the micelle corona by pH-sensitive poly (ethylenimine) (PEI). The size swelling/shrinking property of the micelles induced by temperature decrease/increase was used as a switch to control the fluorescence yield of the nanocapsules. It was found that the fluorescence yield significantly increased with the increase in temperature. The PEI cross-link made the fluorescence yield also sensitive to local pH ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5379394 Mon, 31 Oct 2011 04:00:00 +0100 5379394 http://www.medworm.com/index.php?rid=5379397&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22035370%26dopt%3DAbstract Authors: Orelma H, Filpponen I, Johansson LS, Laine J, Rojas OJ Abstract The adsorption of human immunoglobulin G (hIgG) and bovine serum albumin (BSA) on cellulose supports were investigated. The dynamics and extent of related adsorption processes were monitored by surface plasmon resonance (SPR) and quartz crystal microbalance with dissipation monitoring (QCM-D). Amine groups were installed on the cellulose substrate by adsorption of chitosan from aqueous solution, which allowed for hIgG to physisorb from acid media and produced a functionalized substrate with high surface density (10 mg/m2). hIgG adsorption from neutral and alkaline conditions was found to yield lower adsorbed amounts. The installation of the carboxyl groups on cellulose substrate via carboxymethylated cellulose... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5379397 Fri, 28 Oct 2011 04:00:00 +0100 5379397 http://www.medworm.com/index.php?rid=5360993&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22032302%26dopt%3DAbstract Authors: Antunes JC, Leite Pereira C, Molinos M, Ferreira-da-Silva F, Dessi M, Gloria A, Ambrosio L, Gonçalves RM, Barbosa MA Abstract Chitosan (Ch) is a non-toxic and biocompatible polysaccharide extensively used in biomedical applications. Ch, as a polycation, can be combined with anionic polymers by layer-by-layer (LbL) self-assembly, giving rise to multilayered complexed architectures. These structures can be used in tissue engineering strategies, as drug delivery systems, or artificial matrices mimicking the extracellular microenvironment. In this work, Ch was combined with poly(γ-glutamic acid) (γ-PGA). γ-PGA is a polyanion, which was microbially produced, and is known for its low immunogenic reaction and low cytotoxicity. Multilayered ultrathin films were assembled by Lb... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5360993 Fri, 28 Oct 2011 04:00:00 +0100 5360993 http://www.medworm.com/index.php?rid=5360996&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22029379%26dopt%3DAbstract Authors: Pepe-Mooney BJ, Kokona B, Fairman R Abstract Photoelectronically conductive self-assembling peptide-porphyrin assemblies have great potential in their use as biomaterials owing largely to their environmentally responsive properties. We have successfully designed a coiled-coil peptide that can self-assemble to form mesoscale filaments and serve as a scaffold for porphyrin interaction. In our earlier work, peptide-porphyrin-based biomaterials were formed at neutral pH but the structures were irregular at the nano- to micro-scale size range, as judged by atomic force microscopy. We identified a pH in which mesoscale fibrils were formed, taking advantage of the types of porphyrin interactions that are present in well-characterized J-aggregates. We used UV-visible spectroscopy,... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5360996 Thu, 27 Oct 2011 04:00:00 +0100 5360996 http://www.medworm.com/index.php?rid=5360995&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22029823%26dopt%3DAbstract This study successfully evaluated gene delivery and transfection toward rat C6 glioma cell lines mediated by intrinsic blue fluorescent poly(amido amine) (PAMAM) dendrimer. We used three antisense oligonucleotides, (AS-ODN) p75, NGF1, and NGF2 for knocking down specific protein expressions. The three oligonucleotides were electrostatically associated with the photoluminescent amino-terminated PAMAM dendrimer to yield fluorescent complexes at various nitrogen-to-phosphorous (N/P) ratios. Compared with pristine PAMAM dendrimer and hyperbranched polyethylenimine (PEI), the fluorescent PAMAM dendrimer revealed lower in vitro cytotoxicity toward C6 cells, allowing us to transfect the cells with the AS-ODN complexes under a higher N/P ratio. Due to the intrinsic fluorescence, cellular uptake beh... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5360995 Thu, 27 Oct 2011 04:00:00 +0100 5360995 http://www.medworm.com/index.php?rid=5360994&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22029860%26dopt%3DAbstract In this study, the hydrophobic region, a molecular switch of the human serum albumin (HSA), was regulated to form HSA-paclitaxel (HSA-PTX) nanoparticles by a facile route. High-resolution transmission electron microscopy and fluorescence quenching indicate that HSA co-assembled with PTX, which acts as a bridge to form core-shell nanoparticles about 50 ～240 nm in size, and that PTX might bind to the subdomain IIA sites of HSA. Change of ultraviolet absorption and circular dichroism spectra reveal the formation of HSA-PTX nanoparticles, which possess tumor targeting capability in vivo image. This method to prepare nanocarrier systems for hydrophobic guest molecules reveals a general principle of self-assembly for other plasma proteins and other pharmacologically active substances with poor... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5360994 Thu, 27 Oct 2011 04:00:00 +0100 5360994 http://www.medworm.com/index.php?rid=5360997&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22026464%26dopt%3DAbstract Authors: Dai M, Haghpanah JS, Singh N, Roth EW, Liang A, Tu RS, Montclare JK Abstract We have generated protein block polymer E<sub>n</sub>C and CE<sub>n</sub> libraries comprised of two different self-assembling domains (SADs) derived from elastin (E) and the cartilage oligomeric matrix protein coiled-coil (C). As the E domain is shortened, the polymers exhibit an increase in inverse transition temperature (T<sub>t</sub>), however the range of temperature change differs dramatically between the E<sub>n</sub>C and CE<sub>n</sub> library. While all polymers assemble into nanoparticles, the bulk mechanical properties of the E<sub>n</sub>C are very different than CE<sub>n</sub>. The E<sub>n</s... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5360997 Wed, 26 Oct 2011 04:00:00 +0100 5360997 http://www.medworm.com/index.php?rid=5360998&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22026411%26dopt%3DAbstract Authors: Martinez JS, Keller TC, Schlenoff JB Abstract The cytotoxicity of polyelectrolytes commonly employed for layer-by-layer deposition of polyelectrolyte multilayers (PEMUs) was assessed using rat smooth muscle A7r5 and human osteosarcoma U-2 OS cells. Cell growth, viability, and metabolic assays were used to compare the responses of both cell lines to poly(acrylic acid), PAA, and poly(allylamine hydrochloride), PAH, in solution at concentrations up to 10 mM and to varying thicknesses of (PAA/PAH) PEMUs. Cytotoxicity correlated with increasing concentration of solution polyelectrolytes for both cell types and was greater for the positively charged PAH than for the negatively charged PAA. While metabolism and proliferation of both cell types was slower on PEMUs than on tissue c... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5360998 Tue, 25 Oct 2011 04:00:00 +0100 5360998 http://www.medworm.com/index.php?rid=5360999&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22023267%26dopt%3DAbstract Rapid, high resolution screening of biomaterial hydrogelators by μ<sup>2</sup>rheology. Biomacromolecules. 2011 Oct 24; Authors: Schultz KM, Bayles AV, Baldwin AD, Kiick KL, Furst EM Abstract A combination of sample manipulation and rheological characterization at the micro-scale is used to identify the gelation of poly(ethylene glycol)-heparin hydrogels over a wide range of compositions. A microfluidic device produces 50-100 droplet samples, each with a different composition. Multiple particle tracking microrheology is used to measure the rheology of each sample. This combination requires little material and enables efficient and rapid screening of gelation conditions. The high resolution data identifies the gelation reaction percolation boundaries and a lower... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5360999 Mon, 24 Oct 2011 04:00:00 +0100 5360999 http://www.medworm.com/index.php?rid=5361000&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22017359%26dopt%3DAbstract Authors: Yu SS, Koblin RL, Zachman AL, Perrien DS, Hofmeister LH, Giorgio TD, Sung HJ Abstract Chronic inflammation-mediated oxidative stress is a common mechanism of implant rejection and failure. Therefore, polymer scaffolds that can degrade slowly in response to this environment may provide a viable platform for implant site-specific, sustained release of immunomodulatory agents over a long time period. In this work, proline oligomers of varying lengths (Pn) were synthesized and exposed to oxidative environments, and their accelerated degradation under oxidative conditions was verified via high performance liquid chromatography and gel permeation chromatography. Next, diblock copolymers of poly(ethylene glycol) (PEG) and poly(ε-caprolactone) (PCL) were carboxylated to form 100 ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5361000 Sun, 23 Oct 2011 04:00:00 +0100 5361000 http://www.medworm.com/index.php?rid=5361001&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22017338%26dopt%3DAbstract Authors: Schütz CA, Juillerat-Jeanneret L, Käuper P, Wandrey C Abstract Hydrophilic nanocarriers formed by electrostatic interaction of chitosan with oppositely charged macromolecules have a high potential as vectors in biomedical and pharmaceutical applications. However, comprehensive information about the fate of such nanomaterials in biological environment is lacking. We used chitosan from both animal and fungal sources to form well-characterized chitosan-pentasodium triphosphate (TPP)//alginate nanogels suitable for comparative studies. Upon exposure of human colon cancer cells (HT29 and CaCo2), breast cancer cells (MDA MB 231 and MCF 7), glioblastoma cells (LN229), lung cancer cells (A549) and brain-derived endothelial cells (HCEC) to chitosan-(TPP)//alginate nanogels, cell ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5361001 Fri, 21 Oct 2011 04:00:00 +0100 5361001 http://www.medworm.com/index.php?rid=5344499&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21988210%26dopt%3DAbstract Authors: Annaka M, Mortensen K, Vigild ME, Matsuura T, Tsuji S, Ueda T, Tsujinaka H Abstract To adapt the physical properties of living materials to their biological function, nature developed various types of polymers with outstanding physical behavior. One example is the vitreous body, which is important intraocular elements not only because of its optical and mechanical performances, but also due to its important role in the pathogenesis and treatment of conditions affecting adjacent tissues and eventually the whole eye. Here, we report a novel biocompatible material for injectable vitreous substitute, composed of thermosensitive amphiphilic polymer, which is capable of forming a transparent gel in the vitreous cavity. It is nontoxic, provides adequate support for the retina, an... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5344499 Thu, 20 Oct 2011 04:00:00 +0100 5344499 http://www.medworm.com/index.php?rid=5344496&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21995723%26dopt%3DAbstract Authors: Fukuzumi H, Saito T, Iwamoto S, Kumamoto Y, Ohdaira T, Suzuki R, Isogai A Abstract Wood cellulose nanofibril films with sodium carboxylate groups prepared from a 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized pulp exhibited an extremely low oxygen permeability of 0.0008 mL μm m(-2) day(-1) kPa(-1) at 0% relative humidity (RH). Positron annihilation lifetime spectroscopy (PALS) was used to determine the pore sizes in wood and tunicate TEMPO-oxidized cellulose nanofibril (TOCN-COONa) films in a vacuum (i.e., at 0% RH). PALS analysis revealed that the pore size of the wood TOCN-COONa films remained nearly at 0.47 nm from the film surface to the interior of the film. This is probably the cause of this high oxygen-barrier properties at 0% RH. The crystalline structure o... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5344496 Wed, 19 Oct 2011 04:00:00 +0100 5344496 http://www.medworm.com/index.php?rid=5344480&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22011361%26dopt%3DAbstract Authors: Sano KI, Kawamura R, Tominaga T, Oda N, Ijiro K, Osada Y Abstract A chemically cross-linked filamentous actin (F-actin) gel consisting of globular actin (G-actin) as repeating units was prepared. The F-actin gel was cross-linked by covalent bonds and the main-chain is represented by the self-assembly of G-actin with a high-ordered hierarchical structure. The gel exhibited good mechanical performance with a storage modulus > 1 kPa, and undergoes reversible sol-gel transitions in response to changes in the salt concentration (chemical-induced sol-gel transition) as well as to shear strain (mechanical-induced sol-gel transition). Thus, the gel exhibits self-repairing ability through dynamic polymerization and depolymerization across the structure hierarchies under repeated... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5344480 Wed, 19 Oct 2011 04:00:00 +0100 5344480 http://www.medworm.com/index.php?rid=5344487&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22007721%26dopt%3DAbstract Authors: Synatschke CV, Schallon A, Jerome V, Freitag R, Mueller AH Abstract Nonviral gene delivery with the help of polycations has raised considerable interest in the scientific community over the last decades. Herein, we present a systematic study on the influence of the molecular weight and architecture of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) on the transfection efficiency and the cytotoxicity in CHO-K1 cells. A library of well defined homopolymers with a linear and star-shaped topology (3- and 5-arm stars) was synthesized via atom transfer radical polymerization (ATRP). The molecular weights of the polycations ranged from 16 to 158 kDa. We found that while polymers of the same architecture with a larger molecular weight were more toxic, the cytotoxicity at a giv... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5344487 Tue, 18 Oct 2011 04:00:00 +0100 5344487 http://www.medworm.com/index.php?rid=5344486&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22007750%26dopt%3DAbstract Authors: Sivakumaran D, Maitland D, Hoare T Abstract The design and application of soft nanocomposite injectable hydrogels containing entrapped microgels for small molecule drug delivery is demonstrated. Copolymer microgels based on N-isopropylacrylamide and acrylic acid were synthesized that exhibited both ionic and hydrophobic affinity for binding to bupivacaine, a cationic local anesthetic used as a model drug. Microgels were subsequently immobilized within an in situ-gelling hydrogel network crosslinked via hydrazide-aldehyde chemistry to generate hydrogel-microgel soft nanocomposites. Drug release could be sustained for up to 60 days from these nanocomposite hydrogels, significantly longer than that achievable using the constituent hydrogel or microgels alone (less than one we... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5344486 Tue, 18 Oct 2011 04:00:00 +0100 5344486 http://www.medworm.com/index.php?rid=5344488&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22004188%26dopt%3DAbstract Authors: Pawar SN, Edgar KJ Abstract Alginates are (1→4) linked linear copolysaccharides composed of β-D-mannuronic acid (M) and its C-5 epimer, α-L-guluronic acid (G). Several strategies to synthesize organically modified alginate derivatives have been reported, but almost all chemistries are performed in either aqueous or aqueous-organic media. The ability to react alginates homogeneously in organic solvents would open up access to a wide range of new chemistries and derivatives. However, past attempts have been restricted by the absence of methods for alginate dissolution in organic media. We therefore report a strategy to dissolve tetrabutylammonium (TBA) salts of alginic acid in polar aprotic solvents containing tetrabutylammonium fluoride (TBAF). Acylation of TBA-alginate... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5344488 Mon, 17 Oct 2011 04:00:00 +0100 5344488 http://www.medworm.com/index.php?rid=5344494&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21999108%26dopt%3DAbstract In this study, the behaviour of BC membranes as systems for topical delivery of lidocaine was evaluated. The BC-lidocaine membranes were prepared and characterized in terms of structural and morphological properties. A uniform distribution of the drug inside the BC membranes was observed. In vitro diffusion studies with Franz cells were conducted using human epidermal membranes and showed that the permeation rate of the drug in BC membranes was slightly slower than that obtained with the conventional systems, which was attributed to the establishment of interactions between the lidocaine molecules and the BC membrane, as evidenced by FTIR and NMR analysis. These results indicate that this methodology can be successfully applied for the dermal administration of lidocaine, regarding the rele... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5344494 Sun, 16 Oct 2011 04:00:00 +0100 5344494 http://www.medworm.com/index.php?rid=5344493&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21999900%26dopt%3DAbstract Authors: Dargaville BL, Vaquette C, Peng H, Rasoul F, Chau YQ, Cooper-White JJ, Campbell JH, Whittaker AK Abstract A series of copolymers of trimethylene carbonate (TMC) and L-lactide (LLA) were synthesized and evaluated as scaffolds for the production of artificial blood vessels. The polymers were end-functionalized with acrylate, cast into films and crosslinked using UV light. The mechanical, degradation and biocompatibility properties were evaluated. High TMC polymers showed mechanical properties comparable to human arteries (Young's moduli of 1.2 - 1.8 MPa and high elasticity with repeated cycling at 10 % strain). Over 84 days degradation in PBS, the modulus and material strength decreased gradually. The polymers were non-toxic and showed good cell adhesion and proliferation ov... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5344493 Fri, 14 Oct 2011 04:00:00 +0100 5344493 http://www.medworm.com/index.php?rid=5344498&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21995461%26dopt%3DAbstract Authors: Donati I, Feresini M, Travan A, Marsich E, Lapasin R, Paoletti S Abstract The present contribution deals with the preparation and characterization of ternary mixtures of polysaccharides with potential applications in the field of tissue engineering. Two natural polyanions, i.e., alginate and hyaluronic acid, and a polycation, a lactose-modified chitosan (chitlac), were mixed in dilute conditions. The miscibility between the three components was explored in the presence of different amounts of supporting simple salt. These analyses allowed to identify the experimental conditions avoiding polymer phase separation and leading to either solution of independent polymers or soluble nonstoichiometric interpolyelectrolyte complexes. The characterization of the interpolyelectrolyte... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5344498 Thu, 13 Oct 2011 04:00:00 +0100 5344498 http://www.medworm.com/index.php?rid=5344497&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21995513%26dopt%3DAbstract Authors: Rhee JK, Hovlid M, Fiedler JD, Brown SD, Manzenrieder F, Kitagishi H, Nycholat C, Paulson JC, Finn MG Abstract Qβ virus-like particles encapsulating multiple copies of fluorescent proteins were generated in high yields using a modular system enhanced by specific engineered RNA-protein interactions. The resulting particles were structurally indistinguishable from recombinant Qβ alone. The encapsidated proteins were nearly identical in photochemical properties to monomeric analogues, were more stable toward thermal degradation, and were protected from proteolytic cleavage. Residues on the outer capsid surface were chemically derivatized by acylation and azide-alkyne cycloaddition without affecting the fluorescence properties of the packaged proteins. A high-affinity carboh... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5344497 Thu, 13 Oct 2011 04:00:00 +0100 5344497 http://www.medworm.com/index.php?rid=5344495&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21995760%26dopt%3DAbstract Authors: Hollingsworth JV, Richard AJ, Vicente MG, Russo PS Abstract ABSTRACT: The aggregation of meso-tetra(4-sulfonatophenyl)porphyrin (H2TPPS4-) in phosphate solutions was investigated as a function of pH, concentration, time, ionic strength, and solution preparation (either from dilution of a freshly prepared 2 mM stock or by direct preparation of µM solution concentrations) using a combination of complementary analytical techniques. UV-Vis and fluorescence spectroscopy indicated the formation of staggered, side-by-side (J-type) assemblies. Their size and self-associative behavior was determined using analytical ultracentrifugation and small angle X-ray scattering. Our results indicate that in neutral and basic solutions of H2TPPS4-, porphyrin dimers and trimers are formed at ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5344495 Thu, 13 Oct 2011 04:00:00 +0100 5344495 http://www.medworm.com/index.php?rid=5344500&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21988133%26dopt%3DAbstract Authors: Abdelkafi F, Ammar H, Rousseau B, Tessier M, El Gharbi R, Fradet A Abstract Alfa grass lignin obtained by the acetic acid/formic acid/water CIMV pulping process was characterized by FTIR and (1)H, (13)C-(1)H 2D HSQC, and (31)P NMR spectroscopies. Lignin samples purified by further dissolution/precipitation or basic hydrolysis steps were also analyzed. The CIMV alfa lignin is a mixture of low molar mass compounds (M(n) = 1500 g/mol) of SGH type with β-O-4 ether bonds as the major interunit linkage. The crude lignin contains fatty acids and residual polysaccharides. It also contains large amounts of acetate and hydroxycinnamates, mostly in the γ-position of β-O-4 interunit linkages. Although partial acetylation induced by the process cannot be excluded, the absence of aro... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5344500 Tue, 11 Oct 2011 04:00:00 +0100 5344500 http://www.medworm.com/index.php?rid=5344502&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21981120%26dopt%3DAbstract In this study, the potential damage of the pulmonary epithelium upon exposure to poly(lactide-co-glycolide) (PLGA) NPs has been assessed in vitro using a Calu-3-based model of the bronchial epithelial barrier. Positively and negatively charged as well as neutral PLGA NPs were obtained by coating their surface with chitosan (CS), poloxamer (PF68) or poly(vinyl alcohol) (PVA), respectively. The role of NP surface chemistry and charge on the epithelial resistance and mucus turnover, using MUC5AC as a marker, was investigated. The interaction with mucin reduced the penetration of CS- and PVA-coated NPs while the hydrophilic PF68-coated NPs diffused across the mucus barrier leading to a higher intracellular accumulation. Only CS-coated NPs caused a transient but reversible decrease of the trans... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5344502 Fri, 07 Oct 2011 04:00:00 +0100 5344502 http://www.medworm.com/index.php?rid=5344501&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21981266%26dopt%3DAbstract Authors: Kljun A, Benians TA, Goubet F, Meulewaeter F, Knox JP, Blackburn RS Abstract Cotton fiber cellulose is highly crystalline and oriented; when native cellulose (cellulose I) is treated with certain alkali concentrations, inter-molecular hydrogen bonds are broken and Na-cellulose I is formed. At higher alkali concentrations Na-cellulose II forms, wherein inter-molecular and intra-molecular hydrogen bonds are broken, ultimately resulting in cellulose II polymers. Crystallinity changes in cotton fibers were observed and assigned using attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy and x-ray diffraction (XRD) subsequent to sodium hydroxide treatment and compared with an in situ protein-binding methodology using cellulose-directed carbohydrate-bi... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5344501 Fri, 07 Oct 2011 04:00:00 +0100 5344501 http://www.medworm.com/index.php?rid=5296316&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21978096%26dopt%3DAbstract Authors: Li X, Wu P, Gao GF, Cheng S Abstract The high transmissibility and genetic variability of influenza virus have made the design of effective approaches to control the infection particularly challenging. The virus surface hemagglutinin (HA) protein is responsible for the viral attachment to host cell surface via the binding with its glycoligands such as sialyllactose (SL), and thereby an attractive target for antiviral designs. Herein we present the facile construction and development of two SL-incorporated chitosan-based materials, either as a water-soluble polymer or as a functional fiber, to demonstrate their abilities for the viral adhesion inhibition and decontamination. The syntheses were accomplished by grafting a lactoside bearing an aldehyde-functionalized aglycone ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5296316 Thu, 06 Oct 2011 04:00:00 +0100 5296316 http://www.medworm.com/index.php?rid=5296318&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21972885%26dopt%3DAbstract Authors: Zhao C, Zheng J Abstract Development of biomaterials with long-term biocompatibility, durability, and stability remains a critical challenge for biomedical devices. Here, we synthesize, characterize, and graft poly(N-(2-Hydroxyethyl)acrylamide) (polyHEAA) onto both gold surfaces and gold nanoparticles (AuNPs) via surface-initiated atom transfer radical polymerization (SI-ATRP) to form a stable antifouling coating to resist nonspecific protein adsorption and bacterial attachment. Surface plasmon resonance (SPR) results demonstrate that all of polyHEAA brushes coated on the gold substrate at a wide range of film thickness of ~10-40 nm can achieve almost zero protein adsorption from undiluted blood plasma and serum for 1 hour, while static bacteria assay results show that pol... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5296318 Wed, 05 Oct 2011 04:00:00 +0100 5296318 http://www.medworm.com/index.php?rid=5296317&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21972921%26dopt%3DAbstract Authors: Ghoorchian A, Holland NB Abstract Elastin-like polypeptides are thermally responsive polymers that exhibit phase separation above a transition temperature. The effect of molecular architecture on the temperature responsive behavior of elastin-like polypeptide solutions was investigated by characterization of solutions of three-armed star polypeptides, linear polypeptides, and their mixtures. These biosynthesized polypeptides have precise lengths and amino acid sequences. Transition temperatures were measured as a function of molecular weight and solution concentration and compared to their linear counterparts. Like their linear counterparts, the transition temperature is linearly related to log concentration. A mathematical relationship was used to fit the transition tempe... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5296317 Wed, 05 Oct 2011 04:00:00 +0100 5296317 http://www.medworm.com/index.php?rid=5296321&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21936499%26dopt%3DAbstract Authors: Meyer F, Raquez JM, Verge P, Martínez de Arenaza I, Coto B, Van Der Voort P, Meaurio E, Dervaux B, Sarasua JR, Du Prez F, Dubois P Abstract This work relies on the CNT dispersion in either solution or a polymer matrix through the formation of a three-component supramolecular system composed of PEO-b-PLLA diblock copolymer, carbon nanotubes (CNTs), and lithium chloride. According to a one-pot procedure in solution, the "self-assembly" concept has demonstrated its efficiency using suspension tests of CNTs. Characterizations of the supramolecular system by photon correlation spectroscopy, Raman spectroscopy, and molecular dynamics simulations highlight the charge transfer interaction from the CNTs toward the PEO-b-PLLA/LiCl complex. Finally, this concept was successfully ext... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5296321 Tue, 04 Oct 2011 04:00:00 +0100 5296321 http://www.medworm.com/index.php?rid=5296320&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21970466%26dopt%3DAbstract We present a study of the adsorption of a positively charged protein to a positively charged spherical polyelectrolyte brush (SPB) by isothermal titration calorimetry (ITC). ITC is used to determine the adsorption isotherm as a function of temperature and of salt concentration (at physiological pH 7.2). At low ionic strength, RNase A is strongly adsorbed by the SPB particles despite the fact that both the SPB particles and the protein are positively charged. Virtually no adsorption takes place when the ionic strength is raised through added salt. This is strong evidence for counterion release as the primary driving force for protein adsorption. We calculated that ~2 counterions were released upon RNase A binding. The adsorption of RNase A into like-charged SPB particles is entropy-driven, ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5296320 Tue, 04 Oct 2011 04:00:00 +0100 5296320 http://www.medworm.com/index.php?rid=5296319&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21970513%26dopt%3DAbstract Authors: Popa EG, Gomes ME, Reis RL Abstract The present work was focused on the development and characterization of new hydrogel systems based on natural origin polymers, namely alginate and carrageenan, into different formats and with adequate properties to sustain the viability of encapsulated cells, envisioning their application as cell delivery vehicles for tissues regeneration. Different formulations of alginate and carrageenan hydrogels and different processing parameters were considered in order to determine the best conditions required to achieve the most adequate response in terms of the mechanical stability, cell viability and functionality of the developed systems. The morphology, size and structure of the hydrogels and their degradation behavior and mechanical properti... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5296319 Tue, 04 Oct 2011 04:00:00 +0100 5296319 http://www.medworm.com/index.php?rid=5296323&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21955251%26dopt%3DAbstract We report a new class of cationic amphiphilic peptides with short sequences, G(IIKK)(n)I-NH(2) (n = 1-4), that can kill Gram-positive and Gram-negative bacteria as effectively as several well-known antimicrobial peptides and antibiotics. In addition, some of these peptides possess potent antitumor activities against cancer cell lines. Moreover, their hemolytic activities against human red blood cells (hRBCs) remain remarkably low even at some 10-fold bactericidal minimum inhibitory concentrations (MICs). When bacteria or tumor cells are cocultured with NIH 3T3 fibroblast cells, G(IIKK)(3)I-NH(2) showed fast and strong selectivity against microbial or tumor cells, without any adverse effect on NIH 3T3 cells. The high selectivity and associated features are attributed to two design tactics: ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5296323 Mon, 03 Oct 2011 04:00:00 +0100 5296323 http://www.medworm.com/index.php?rid=5296322&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21967486%26dopt%3DAbstract In this study, hyaluronic acid (HA) was functionalized to exhibit controlled and tunable mechanics and degradation once crosslinked, in an attempt to assess the temporal dependency of mechanical stabilization in LV remodeling. Specifically, two hydrolytically degrading (low and high HeMA-HA, degrading in ~3 and 10 weeks, respectively) and two stable (low and high MeHA, little mass loss even after 8 weeks) hydrogels with similar initial mechanics (low: ~7 kPa, high: ~35-40 kPa) were evaluated in an ovine model of MI. Generally, the more stable hydrogels maintained myocardial wall thickness in the apical and basilar regions more efficiently (low MeHA: apical: 6.5mm, basilar: 7mm, high MeHA: apical: 7.0mm basilar: 7.2mm) than the hydrolytically degrading hydrogels (low HeMA-HA: apical: 3.5mm,... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5296322 Mon, 03 Oct 2011 04:00:00 +0100 5296322 http://www.medworm.com/index.php?rid=5296324&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21961886%26dopt%3DAbstract In this study, we report a facile, single-step approach for the synthesis of an N-alkylated amino acid as an AB-type functional monomer to generate a novel pseudo-poly(amino acid), without using the laborious multistep, protection-deprotection methods. This synthetic strategy is reproducible, easy to scale up, and does not produce toxic byproducts. In addition, the synthesized amino acid-based polymer is different from conventional linear polymers as the butyl pendants enhance its solubility in common organic solvents and facilitate the creation of hydrophobic nanocavities for the effective encapsulation of hydrophobic cargos upon nanoparticle formation. Within the nanoparticles, we have encapsulated a hydrophobic DiI dye and a therapeutic drug, Taxol. In addition, we have conjugated folic... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5296324 Fri, 30 Sep 2011 04:00:00 +0100 5296324 http://www.medworm.com/index.php?rid=5277676&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21958293%26dopt%3DAbstract Authors: Rudiuk S, Saito H, Hara T, Inoue T, Yoshikawa K, Baigl D Abstract AzoTAB, a photosensitive azobenzene cationic surfactant, which photo-triggers translation activity through light-regulated condensation of mRNA, is added to a translation solution containing several mRNAs, which can be selectively silenced by specific small RNAs. We find that gene silencing by small RNAs remains functional regardless of AzoTAB concentration and UV illumination. In the absence of UV, the translation of all genes present in the medium is partially to fully inhibited depending on AzoTAB concentration. In contrast, the application of a short UV stimulus (365 nm for 1.5 min) results in the selective photo-activation of genes that are not silenced by small RNA. These results show that light-regula... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5277676 Thu, 29 Sep 2011 04:00:00 +0100 5277676 http://www.medworm.com/index.php?rid=5277684&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21936509%26dopt%3DAbstract Authors: Krajewska B, Wydro P, Jańczyk A Abstract Chitosan, a cationic biopolymer derived from chitin, has been described as having antibacterial activity. The modes of this activity, however, have not been established. One mode proposed is that chitosan perturbs bacterial cell membranes. To validate this proposal, in this study we investigated chitosan interactions with lipids in Langmuir monolayers as model membranes. The interactions were assessed by monitoring differences in the shape of the compression isotherms measured in the absence and presence of chitosan in the subphase (acetate buffer). To appraise the contribution of electrostatic interactions versus hydrogen bonding and hydrophobic interactions, three membrane lipids differing in charge were studied-anionic dipalmito... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5277684 Wed, 28 Sep 2011 04:00:00 +0100 5277684 http://www.medworm.com/index.php?rid=5277683&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21954830%26dopt%3DAbstract Authors: Masic A, Bertinetti L, Schuetz R, Galvis L, Timofeeva N, Dunlop JW, Seto J, Hartmann MA, Fratzl P Abstract Collagen is a versatile structural molecule in Nature and is used as a building block in many highly organized tissues, such as bone, skin, and cornea. The functionality and performance of these tissues is controlled by their hierarchical organization ranging from the molecular up to macroscopic length scales. In the present study, polarized Raman micro-spectroscopic and imaging analyses were used to elucidate collagen fibril orientation at various levels of structure in native rat tail tendon under mechanical load. In situ humidity-controlled uniaxial tensile tests have been performed concurrently with Raman confocal microscopy to evaluate strain-induced chemical and... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5277683 Wed, 28 Sep 2011 04:00:00 +0100 5277683 http://www.medworm.com/index.php?rid=5277682&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21954860%26dopt%3DAbstract Authors: Khondee S, Olsen CM, Zeng Y, Middaugh CR, Berkland CJ Abstract Repifermin, a truncated form of fibroblast growth factor-10 (FGF-10) also known as keratinocyte growth factor-2 (KGF-2), is a heparin-binding protein with potent regenerative properties. The protein unfolds and aggregates at relatively low temperature (~37 <sup>o</sup>C). Electrostatic interactions between polyanions and several FGFs have been reported to enhance the thermal stability of these proteins. Polyethylene glycol (PEG) was grafted to the polyanions pentosan polysulfate (PPS) and dextran sulfate (DS) as an alternative means to stabilize and non-covalently PEGylate KGF-2. Physical characteristics of KGF-2:polyanion-PEG complexes were examined using a variety of methods including circular dic... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5277682 Wed, 28 Sep 2011 04:00:00 +0100 5277682 http://www.medworm.com/index.php?rid=5277681&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21955116%26dopt%3DAbstract We describe the synthesis of metal-chelating polymers (MCPs) with four different pendant polyaminocarboxylate ligands (EDTA, DTPA, TTHA, DOTA) and an orthogonal end-group, either a fluorescein molecule or a bismaleimide linker for antibody attachment. Polymer characterization by a combination of (1)H NMR, UV/vis absorption measurements, and thermal gravimetric analysis (TGA) indicated that each chain of the fluorescein-terminated polymers contained one dye molecule. These polymer samples were loaded with three different types of lanthanide ions as well as palladium and platinum ions. The numbers of metal atoms per chain were determined by a combination of UV/vis and conventional ICP-MS measurements. The experiments with lanthanide ions demonstrated that a net anionic charge on the polymer ... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5277681 Wed, 28 Sep 2011 04:00:00 +0100 5277681 http://www.medworm.com/index.php?rid=5277680&cid=s_37601_60_f&fid=37601&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21955178%26dopt%3DAbstract Authors: Xia X, Xu Q, Hu X, Qin G, Kaplan DL Abstract Silk-elastin-like protein polymers (SELPs), consisting of the repeating units of silk and elastin blocks, combine a set of outstanding physical and biological properties of silk and elastin. Due to the unique properties, SELPs have been widely fabricated into various materials for the applications in drug delivery and tissue engineering. However, little is known about the fundamental self-assembly characteristics of these remarkable polymers. Here we propose a two-step self-assembly process of SELPs in aqueous solution for the first time and report the importance of the ratio of silk to elastin blocks in a SELP's repeating unit on the assembly of the SELP. Through precise tuning of the ratio of silk to elastin, various structure... Biomacromolecules journals http://www.medworm.com/rss/comments.php?id=5277680 Wed, 28 Sep 2011 04:00:00 +0100 5277680