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Efficient siRNA delivery to mammalian cells using layered double hydroxide nanoparticles.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Although siRNAs have surpassed expectations in experiments to alter gene expression in vitro, the lack of an efficient in vivo delivery system still remains a challenge in siRNA therapeutics development and has been recognized as a major hurdle for clinical applications. In this paper we describe an inorganic nanoparticle-based delivery system that is readily adaptable for in vivo systems. Layered double hydroxide (LDH) nanoparticles, a family of inorganic crystals, tightly bind, protect, and release siRNA molecules and deliver them efficiently to mammalian cells in vitro. The uptake of siRNA-loaded LDH nanoparticles o...
Source: Biomaterials - November 16, 2009 Category: Materials Science Authors: Ladewig K, Niebert M, Xu ZP, Gray PP, Lu GQ Tags: Biomaterials Source Type: journals

Engineering fibrin matrices: The engagement of polymerization pockets through fibrin knob technology for the delivery and retention of therapeutic proteins.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Engineering extracellular matrices that utilize the body's natural healing capacity enable the progression of regenerative therapies. Fibrin, widely used as a surgical sealant, is one such matrix that may be augmented by the addition of protein factors to promote cell infiltration and differentiation. The thrombin-catalyzed conversion of fibrinogen to fibrin exposes N-terminal fibrin knobs that bind to C-terminal pockets to form the fibrin network. Here, we have created a platform system for the production of therapeutic proteins that capitalize on these native knob:pocket interactions for protein delivery within fibri...
Source: Biomaterials - November 13, 2009 Category: Materials Science Authors: Soon AS, Stabenfeldt SE, Brown WE, Barker TH Tags: Biomaterials Source Type: journals

The effect of VEGF on the myogenic differentiation of adipose tissue derived stem cells within thermosensitive hydrogel matrices.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We investigated the combination of human adipose tissue derived stem cells (ADSC) and in vivo gel-forming methoxy poly (ethyleneglycol)-poly (varepsilon-caprolactone) (MPEG-PCL) as a muscle regeneration matrix, with and without inclusion of vascular endothelial cell growth factor (VEGF). VEGF(165)-treated stem cell grafts showed significant proliferation and differentiation into muscle tissue in vivo. Importantly, the inclusion of VEGF enhanced vascularization. This scaffold supported preconditioned ADSC, and allowed them to differentiate into mature muscle tissues in vivo, indicating that ADSC of human origin and MPEG...
Source: Biomaterials - November 13, 2009 Category: Materials Science Authors: Kim MH, Hong HN, Hong JP, Park CJ, Kwon SW, Kim SH, Kang G, Kim M Tags: Biomaterials Source Type: journals

The induction of tumor apoptosis in B16 melanoma following STAT3 siRNA delivery with a lipid-substituted polyethylenimine.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we investigated the potential of nanoparticles based on polyethylenimine (PEI) modified with stearic acid (StA), to deliver siRNA for efficient STAT3 downregulation in B16 melanoma cells. The B16 cells were targeted with approximately 6-200nm of siRNA complexes for 36h. Compared to the PEI complexes, the PEI-StA complexes showed higher potency in STAT3 silencing in B16 cells accompanied by a significant induction of IL-6 secretion and a reduction of VEGF production. Moreover, with PEI-StA complexes, the level of the cellular Caspase 3 activity (an indicator of apoptotic activity) was found to be 2.5 times hi...
Source: Biomaterials - November 12, 2009 Category: Materials Science Authors: Alshamsan A, Hamdy S, Samuel J, El-Kadi AO, Lavasanifar A, Uludağ H Tags: Biomaterials Source Type: journals

The effect of timing in the administration of hepatocyte growth factor to modulate BMP-2-induced osteoblast differentiation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study analyzed osteogenic properties of HGF, particularly during BMP-2-induced bone formation. Using a mouse model of ectopic bone formation, HGF-impregnated gelatin sponges displayed significantly reduced bone formation induced by BMP-2, both radiologically and histologically. Abrogation of endogenous HGF production by knockdown of HGF mRNA resulted in upregulation of BMP-2-induced ALP activity for C2C12 myoblasts in vitro. In contrast, addition of exogenous HGF inhibited BMP-2-induced ALP activity and osteocalcin production by mouse embryonic fibroblasts (MEFs) through HGF-c-Met interactions. Inhibition of ALP activ...
Source: Biomaterials - November 11, 2009 Category: Materials Science Authors: Kawasaki T, Niki Y, Miyamoto T, Horiuchi K, Matsumoto M, Aizawa M, Toyama Y Tags: Biomaterials Source Type: journals

A nitric oxide releasing, self assembled peptide amphiphile matrix that mimics native endothelium for coating implantable cardiovascular devices.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cardiovascular disease is the number one cause of death in the United States. Deployment of stents and vascular grafts has been a major therapeutic method for treatment. However, restenosis, incomplete endothelialization, and thrombosis hamper the long term clinical success. As a solution to meet these current challenges, we have developed a native endothelial ECM mimicking self-assembled nanofibrous matrix to serve as a new treatment model. The nanofibrous matrix is formed by self-assembly of peptide amphiphiles (PAs), which contain nitric oxide (NO) donating residues, endothelial cell adhesive ligands composed of YIG...
Source: Biomaterials - November 11, 2009 Category: Materials Science Authors: Kushwaha M, Anderson JM, Bosworth CA, Andukuri A, Minor WP, Lancaster JR, Anderson PG, Brott BC, Jun HW Tags: Biomaterials Source Type: journals

Immunological response to tissue-engineered cartilage derived from auricular chondrocytes and a PLLA scaffold in transgenic mice.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The immune response against biomaterials in tissue-engineered constructs could potentially worsen the outcome of tissue regeneration, but immunological reactions between host and donor in tissue-engineered constructs remain to be clarified. In the present study, we syngenically transplanted tissue-engineered cartilage constructs consisting of C57BL/6 mice auricular chondrocytes and poly-l-lactic acid scaffolds (MW:200,000) into EGFP transgenic mice of C57BL/6 background, and evaluated the response by the localization of donor-derived and host-derived cells, the latter of which were distinguished by the presence of EGFP...
Source: Biomaterials - November 11, 2009 Category: Materials Science Authors: Fujihara Y, Takato T, Hoshi K Tags: Biomaterials Source Type: journals

Dinuclear metal(II) complexes of polybenzimidazole ligands as carriers for DNA delivery.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A metal-based nonviral carrier for DNA-transfer in gene therapy was synthesized and characterized. The strong intermolecular pi-pi contacts are common in the observed dinuclear Cu(2+) and Co(2+) complexes of polybenzimidazole ligands. The affinity assays indicated that the strong binding of the complexes to DNA is driven by both electrostatic attractions between the complexes and DNA and the intercalation of the ligands between DNA base pairs. The typical in vitro studies showed that micromolar doses of each complex tested can efficiently and rapidly condense free DNA, either in linear or circular state, from solutions...
Source: Biomaterials - November 9, 2009 Category: Materials Science Authors: Liu L, Zhang H, Meng X, Yin J, Li D, Liu C Tags: Biomaterials Source Type: journals

Self-initiated surface grafting with poly(2-methacryloyloxyethyl phosphorylcholine) on poly(ether-ether-ketone).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Poly(ether-ether-ketone) (PEEK)s are a group of polymeric biomaterials with excellent mechanical properties and chemical stability. In the present study, we demonstrate the fabrication of an antibiofouling and highly hydrophilic high-density nanometer-scaled layer on the surface of PEEK by photo-induced graft polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) without using any photo-initiators, i.e., "self-initiated surface graft polymerization." Our results indicated that the diphenylketone moiety in the polymer backbone acted as a photo-initiator similar to benzophenone. The density and thickness of the...
Source: Biomaterials - November 9, 2009 Category: Materials Science Authors: Kyomoto M, Moro T, Takatori Y, Kawaguchi H, Nakamura K, Ishihara K Tags: Biomaterials Source Type: journals

The role of protein assembly in dynamically tunable bio-optical tissues.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cephalopods are nicknamed the "masters of disguise" for their highly evolved camouflage mechanisms, including the hallmark ability to rapidly change the color and reflectance of their skin. Previously, reflectin proteins were identified as the major biomaterial component of iridosomes [1], specialized light-reflecting architectures that contribute intense structural color to squid skin, eyes, and organs [2-5]. Supramolecular assembly of reflectin has been recognized as a key property in the protein's function [6]. Here, we report the first cloning and expression of a specific reflectin protein found in the responsive i...
Source: Biomaterials - November 9, 2009 Category: Materials Science Authors: Tao AR, Demartini DG, Izumi M, Sweeney AM, Holt AL, Morse DE Tags: Biomaterials Source Type: journals

Effects of VEGF temporal and spatial presentation on angiogenesis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Therapeutic angiogenesis relies on the delivery of angiogenic factors capable of reversing tissue ischemia. Polymeric materials that can provide spatial and temporal over vascular endothelial growth factor (VEGF) presentation provide clear benefit, but the influence of VEGF dose, temporal, and spatial presentation on the resultant angiogenic process are largely unknown. The influence of the temporal profile of VEGF concentration, dose, and the impact of VEGF spatial distribution on angiogenesis in in vitro models of angiogenesis and ischemic murine limbs was analyzed in this study. Importantly, a profile consisting of ...
Source: Biomaterials - November 9, 2009 Category: Materials Science Authors: Silva EA, Mooney DJ Tags: Biomaterials Source Type: journals

A biomimetic hydrogel based on methacrylated dextran-graft-lysine and gelatin for 3D smooth muscle cell culture.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study reports synthesis of a methacrylate and lysine functionalized dextran and development of hydrogel composite systems based on this material and methacrylamide modified gelatin. The mechanical stiffness and degree of swelling of the hydrogels were varied by manipulation of the degree of functionalization of dextran and gelatin and concentration/composition of precursor solution. Human umbilical artery smooth muscle cells (SMCs) were encapsulated inside hydrogels during gel hardening with photopolymerization. Rapid cell spreading, extensive cellular network formation and high SMC proliferation occurred within softe...
Source: Biomaterials - November 6, 2009 Category: Materials Science Authors: Liu Y, Chan-Park MB Tags: Biomaterials Source Type: journals

Injectable biodegradable hydrogels with tunable mechanical properties for the stimulation of neurogenesic differentiation of human mesenchymal stem cells in 3D culture.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report an injectable hydrogel scaffold system with tunable stiffness for controlling the proliferation rate and differentiation of human mesenchymal stem cells (hMSCs) in a three-dimensional (3D) context in normal growth media. The hydrogels composed of gelatin-hydroxyphenylpropionic acid (Gtn-HPA) conjugate were formed using the oxidative coupling of HPA moieties catalyzed by hydrogen peroxide (H(2)O(2)) and horseradish peroxidase (HRP). The stiffness of the hydrogels was readily tuned by varying the H(2)O(2) concentration without changing the concentration of polymer precursor. We found that the hydrogel stiffness str...
Source: Biomaterials - November 3, 2009 Category: Materials Science Authors: Wang LS, Chung JE, Pui-Yik Chan P, Kurisawa M Tags: Biomaterials Source Type: journals

Promotion of osteoblast proliferation on complex coacervation-based hyaluronic acid - recombinant mussel adhesive protein coatings on titanium.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Many biological polyelectrolytes are capable of undergoing a fluid-fluid phase separation known as complex coacervation. Coacervates were prepared using hyaluronic acid (HA) and a recombinant fusion protein consisting of mussel adhesive motifs and the RGD peptide (fp-151-RGD). The low interfacial energy of the coacervate was exploited to coat titanium (Ti), a metal widely used in implant materials. The coacervate effectively distributed both HA and fp-151-RGD over the Ti surfaces and enhanced osteoblast proliferation. Approximately half of total fp-151-RGD and HA in the solution transferred to the titanium surface with...
Source: Biomaterials - November 3, 2009 Category: Materials Science Authors: Hwang DS, Waite JH, Tirrell M Tags: Biomaterials Source Type: journals

Surface-energy dependent contact activation of blood factor XII.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Contact activation of blood factor XII (FXII, Hageman factor) in neat-buffer solution exhibits a parabolic profile when scaled as a function of silanized-glass-particle activator surface energy (measured as advancing water adhesion tension tau(a)(o)=gamma(lv)(o)costheta in dyne/cm, where gamma(lv)(o) is water interfacial tension in dyne/cm and theta is the advancing contact angle). Nearly equal activation is observed at the extremes of activator water-wetting properties -36<tau(a)(o)<72dyne/cm (0 degrees </=theta<120 degrees ), falling sharply through a broad minimum within the 20<tau(a)(o)<40dyne/cm ...
Source: Biomaterials - November 3, 2009 Category: Materials Science Authors: Golas A, Parhi P, Dimachkie ZO, Siedlecki CA, Vogler EA Tags: Biomaterials Source Type: journals

The contribution of plasmid design and release to in vivo gene expression following delivery from cationic polymer modified scaffolds.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this report, we investigate the relationship between plasmid release kinetics and the extent and duration of transgene expression. Scaffolds were fabricated from polymer microspheres modified with cationic polymers (polyethylenimine, poly(l-lysine), poly(allylamine hydrochloride), polydiallyldimethylammonium) or polydopamine (PD), with PD enhancing incorporation and slowing release. In vivo implantation of scaffolds into the peritoneal fat pad had no significant changes in the level and duration of transgene expression between PD and unmodified scaffolds. Control studies with plasmid dried onto scaffolds, which exhibite...
Source: Biomaterials - November 3, 2009 Category: Materials Science Authors: Avilés MO, Lin CH, Zelivyanskaya M, Graham JG, Boehler RM, Messersmith PB, Shea LD Tags: Biomaterials Source Type: journals

The use of RGDGWK-lipopeptide to selectively deliver genes to mouse tumor vasculature and its complexation with p53 to inhibit tumor growth.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In vivo selection of phage display libraries have been exploited successfully in the past to isolate various high affinity conformationally strained cyclic peptide ligands (CX(5-7)C, peptides flanked by a cysteine residue on each side) for integrin receptors capable of selectively homing to tumor vasculatures. Previously, such phase display library studies have shown that integrin alpha5beta1 binds with high affinity to cyclic peptides containing CRGDGWC motif. Herein we show that a lipopeptide with just the RGDGW motif (without the flanking cysteine groups) covalently attached to the lysine residue of a monolysinylate...
Source: Biomaterials - November 2, 2009 Category: Materials Science Authors: Samanta S, Sistla R, Chaudhuri A Tags: Biomaterials Source Type: journals

Nanoparticles functionalised with recombinant single chain Fv antibody fragments (scFv) for the magnetic resonance imaging of cancer cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Superparamagnetic iron oxide nanoparticles (SPIONs) can substantially improve the sensitivity of magnetic resonance imaging (MRI). We propose that SPIONs could be used to target and image cancer cells if functionalised with recombinant single chain Fv antibody fragments (scFv). We tested our hypothesis by generating antibody-functionalised (abf) SPIONs using a scFv specific for carcinoembryonic antigen (CEA), an oncofoetal cell surface protein. SPIONs of different hydrodynamic diameter and surface chemistry were investigated and targeting was confirmed by ELISA, cellular iron uptake, confocal laser scanning microscopy ...
Source: Biomaterials - November 2, 2009 Category: Materials Science Authors: Vigor KL, Kyrtatos PG, Minogue S, Al-Jamal KT, Kogelberg H, Tolner B, Kostarelos K, Begent RH, Pankhurst QA, Lythgoe MF, Chester KA Tags: Biomaterials Source Type: journals

The delivery of superoxide dismutase encapsulated in polyketal microparticles to rat myocardium and protection from myocardial ischemia-reperfusion injury.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Oxidative stress is increased in the myocardium following infarction and plays a significant role in death of cardiac myocytes, leading to cardiac dysfunction. Levels of the endogenous antioxidant Cu/Zn-superoxide dismutase (SOD1) decrease following myocardial infarction. While SOD1 gene therapy studies show promise, trials with SOD1 protein have had little success due to poor pharmacokinetics and thus new delivery vehicles are needed. In this work, polyketal particles, a recently developed delivery vehicle, were used to make SOD1-encapsulated-microparticles (PKSOD). Our studies with cultured macrophages demonstrated t...
Source: Biomaterials - November 2, 2009 Category: Materials Science Authors: Seshadri G, Sy JC, Brown M, Dikalov S, Yang SC, Murthy N, Davis ME Tags: Biomaterials Source Type: journals

Engineering a scaffold-free 3D tumor model for in vitro drug penetration studies.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Three-dimensional (3D) in vitro cultures are recognized for recapitulating the physiological microenvironment and exhibiting high concordance with in vivo conditions. In cancer research, the multi-cellular tumor spheroid (MCTS) model is an established 3D cancer model that exhibits microenvironmental heterogeneity close to that of tumors in vivo. However, the established process of MCTS formation is time-consuming and often uncontrolled. Here, we report a method for engineering MCTS using a transient inter-cellular linker which facilitates cell-cell interaction. Using C3A cells (a hepatocellular carcinoma cell line) as ...
Source: Biomaterials - November 2, 2009 Category: Materials Science Authors: Ong SM, Zhao Z, Arooz T, Zhao D, Zhang S, Du T, Wasser M, van Noort D, Yu H Tags: Biomaterials Source Type: journals

Self-Assembly of phospholipid-analogous hyperbranched polymers nanomicelles for drug delivery.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A drug nanocarrier has been constructed through self-assembly of phospholipid analogous hyperbranched polymers (HPHEEP-alkyls) which contain a polar hyperbranched polyphosphate headgroup and many aliphatic tails. HPHEEP-alkyls were synthesized by self-condensing ring-opening polymerization of 2-(2-hydroxyethoxy)ethoxy-2-oxo-1,3,2-dioxaphospholane and then capped with palmitoyl chloride. Benefiting from the amphiphilic structure with the hydrophilic core and many hydrophobic tails, HPHEEP-alkyls were able to self-assemble into nanomicelles in aqueous media. Importantly, the size of the nanomicelles could be controlled c...
Source: Biomaterials - October 31, 2009 Category: Materials Science Authors: Liu J, Pang Y, Huang W, Zhu X, Zhou Y, Yan D Tags: Biomaterials Source Type: journals

Partly PEGylated polyamidoamine dendrimer for tumor-selective targeting of doxorubicin: The effects of PEGylation degree and drug conjugation style.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Partly PEGylated polyamidoamine (PAMAM) dendrimers were used as the carrier for tumor-selective targeting of the anticancer drug doxorubicin (DOX). Acid-sensitive cis-aconityl linkage or acid-insensitive succinic linkage was introduced between DOX and polymeric carriers to produce PPCD or PPSD conjugates, respectively. DOX release from PPCD conjugates followed an acid-triggered manner and increased with increasing PEGylation degree. In vitro cytotoxicity of PPCD conjugates against murine B16 melanoma cells increased with, while cellular uptake decreased with increasing PEGylation degree. PPSD conjugates released neglig...
Source: Biomaterials - October 31, 2009 Category: Materials Science Authors: Zhu S, Hong M, Tang G, Qian L, Lin J, Jiang Y, Pei Y Tags: Biomaterials Source Type: journals

Density functional theory calculations and molecular dynamics simulations of the adsorption of biomolecules on graphene surfaces.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
There is increasing attention in the unique biological and medical properties of graphene, and it is expected that biomaterials incorporating graphene will be developed for the graphene-based drug delivery systems and biomedical devices. Despite the importance of biomolecules-graphene interactions, a detailed understanding of the adsorption mechanism and features of biomolecules onto the surfaces of graphene is lacking. To address this, we have performed density functional theory (DFT) and molecular dynamics (MD) methods exploring the adsorption geometries, adsorption energies, electronic band structures, adsorption is...
Source: Biomaterials - October 30, 2009 Category: Materials Science Authors: Qin W, Li X, Bian WW, Fan XJ, Qi JY Tags: Biomaterials Source Type: journals

The performance of a fly-larva shell-derived chitosan sponge as an absorbable surgical hemostatic agent.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Chitosan is a versatile biomaterial lately used as a new generation of local hemostatic agent approved to date for external use only. Here we introduced a fly-larva shell-derived chitosan sponge (CS) and its feasibility for internal use as an absorbable surgical hemostatic agent was evaluated in a rat hepatic hemorrhage model. CS was a better implantable hemostatic material than gelatin sponge (GS) or oxidized cellulose (OC) in both the acute and chronic bleeding models. The better efficacy of CS may be due to its greater ability to enhance platelet activation, erythrocyte aggregation and morphological alteration, and ...
Source: Biomaterials - October 30, 2009 Category: Materials Science Authors: Gu R, Sun W, Zhou H, Wu Z, Meng Z, Zhu X, Tang Q, Dong J, Dou G Tags: Biomaterials Source Type: journals

The effect of PEGylation of mesoporous silica nanoparticles on nonspecific binding of serum proteins and cellular responses.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Highly ordered MCM-41-type mesoporous silica nanoparticles (MSNs) with particle sizes of 150 +/- 20 nm were prepared and PEGylated by covalently grafting PEGxk chains of different molecular weights (x = 4, 6, 10, 20) and chain densities (0.05 wt%-3.75 wt%) on the outer surface. The influence of molecular weights and chain densities of PEGxk on the nonspecific binding of PEGylated MSNs to human serum protein (HSA) was investigated. The results revealed that the optimal molecular weights should be not less than 10k, and the corresponding optimal chain densities for PEG10k-MSNs and PEG20k-MSNs were 0.75 wt% and 0.075 wt%,...
Source: Biomaterials - October 30, 2009 Category: Materials Science Authors: He Q, Zhang J, Shi J, Zhu Z, Zhang L, Bu W, Guo L, Chen Y Tags: Biomaterials Source Type: journals

The repair of large segmental bone defects in the rabbit with vascularized tissue engineered bone.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report herein the construction of a vascularized tissue engineered bone with mesenchymal stem cells (MSCs) and MSC-derived endothelial cells (ECs) co-cultured in porous beta-tricalcium phosphate ceramic (beta-TCP) to repair 1.5-cm ulnar defects in the rabbit. Examination by X-ray and single photon emission computed tomography (SPECT), histologic analysis, and biomechanical tests were used to evaluate repair and the vascularization of the implants. The results showed that by co-seeding MSCs and MSC-derived ECs, the resulting vascularization was able to promote osteogenesis and improve mechanical properties. The rabbits t...
Source: Biomaterials - October 30, 2009 Category: Materials Science Authors: Zhou J, Lin H, Fang TL, Li X, Dai WD, Uemura T, Dong J Tags: Biomaterials Source Type: journals

Nanotopography-induced changes in focal adhesions, cytoskeletal organization, and mechanical properties of human mesenchymal stem cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The growth of stem cells can be modulated by physical factors such as extracellular matrix nanotopography. We hypothesize that nanotopography modulates cell behavior by changing the integrin clustering and focal adhesion (FA) assembly, leading to changes in cytoskeletal organization and cell mechanical properties. Human mesenchymal stem cells (hMSCs) cultured on 350nm gratings of tissue-culture polystyrene (TCPS) and polydimethylsiloxane (PDMS) showed decreased expression of integrin subunits alpha2, alpha6, alphaV, beta2, beta3 and beta4 compared to the unpatterned controls. On gratings, the elongated hMSCs exhibited ...
Source: Biomaterials - October 29, 2009 Category: Materials Science Authors: Yim EK, Darling EM, Kulangara K, Guilak F, Leong KW Tags: Biomaterials Source Type: journals

Ultrapure chitosan oligomers as carriers for corneal gene transfer.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study lays the foundation for evaluating oligomeric chitosan-DNA nanoparticles as pharmaceuticals for corneal gene therapy, a promising approach for the treatment of acquired and inherited corneal diseases that otherwise lead to blindness. Oligomeric chitosan-DNA nanoparticles can also be evaluated for the treatment of ocular diseases outside of the cornea, and for various additional gene therapy applications. PMID: 19879644 [PubMed - as supplied by publisher] (Source: Biomaterials)
Source: Biomaterials - October 29, 2009 Category: Materials Science Authors: Klausner EA, Zhang Z, Chapman RL, Multack RF, Volin MV Tags: Biomaterials Source Type: journals

The relationship between the nanostructure of titanium surfaces and bacterial attachment.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study examined the adhesion of Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa on conventional Ti, nanorough Ti produced by electron beam evaporation, and nanotubular and nanotextured Ti produced by two different anodization processes. This study found that compared to conventional (nano-smooth) Ti, the nanorough Ti surfaces produced by electron beam evaporation decreased the adherence of all of the aforementioned bacteria the most. The conventional and nanorough Ti surfaces were found to have crystalline TiO(2) while the nanotubular and nanotextured Ti surfaces were found to be amorphous...
Source: Biomaterials - October 29, 2009 Category: Materials Science Authors: Puckett SD, Taylor E, Raimondo T, Webster TJ Tags: Biomaterials Source Type: journals

The role of antibody synergy and membrane fluidity in the vascular targeting of immunoliposomes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report that cellular binding of DOPC immunoliposomes by ECs is maximal at an equimolar ratio of aICAM:aELAM whereas DPPC immunoliposomes showed no ratio dependence and binding was reduced by more than 2-fold. SMCs, which do not express ELAM, show a dependence on aICAM surface density. These results suggest that antibody mobility and molar ratio play a key role in increasing receptor-mediated cell targeting. PMID: 19879646 [PubMed - as supplied by publisher] (Source: Biomaterials)
Source: Biomaterials - October 29, 2009 Category: Materials Science Authors: Gunawan RC, Auguste DT Tags: Biomaterials Source Type: journals

Cationic and thermosensitive protamine conjugated gels for enhancing sustained human growth hormone delivery.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Thermosensitive and cationic poly(organophosphazenes) were designed and synthesized for the sustained delivery of human growth hormone (hGH) charged negatively at the physiological conditions to enhance greatly patient convenience and to improve efficacy and stability. Protamine for a complex formation with hGH was chosen and conjugated to carboxylic acid-terminated poly(organophosphazenes) by a covalent amide linkage. The aqueous solution of the cationic polymer conjugates formed a gel at 37 degrees C regardless of hGH presence. When the conjugate solution was mixed with hGH solution, a complex was formed and free hGH...
Source: Biomaterials - October 29, 2009 Category: Materials Science Authors: Park MR, Chun C, Ahn SW, Ki MH, Cho CS, Song SC Tags: Biomaterials Source Type: journals

Movement of polymer microcarriers using a biomolecular motor.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This work enables polymer microcarriers to be transported on a motor protein coated substrate. The size of microencapsulation system- layered polymer capsules could be controlled through changing heating time during post-treatment. In this active biomimetic system, the microtubules act as shuttles that transport the attached polymer microcarriers. The velocity of the motility does not depend on size of the capsules but the fraction of mobile capsules depends on capsule size and biotinylation proportion of microtubule. The microtubule could also propel dextran-filled capsules to transport the internal components on the ...
Source: Biomaterials - October 29, 2009 Category: Materials Science Authors: Song W, Möhwald H, Li J Tags: Biomaterials Source Type: journals

The biocompatibility of materials used in printed circuit board technologies with respect to primary neuronal and K562 cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we analyzed the in-vitro compatibility of a large set of materials and surface treatments used for LOAC development and evaluation with quasi-standard PCB processes. Biocompatibility was analyzed on hippocampal primary cells (a model of attached cell cultures), in comparison with the reference K562 cell line (a model of cells growing in suspension). We demonstrate here that some of the materials under study alter survival, organization, morphology and adhesion capacity of hippocampal cells, and inhibit growth and differentiation of K562 cells. Nonetheless, a subset of the materials tested did not negatively ...
Source: Biomaterials - October 28, 2009 Category: Materials Science Authors: Mazzuferi M, Bovolenta R, Bocchi M, Braun T, Bauer J, Jung E, Iafelice B, Guerrieri R, Destro F, Borgatti M, Bianchi N, Simonato M, Gambari R Tags: Biomaterials Source Type: journals

Size control of magnetic carbon nanoparticles for drug delivery.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Carbonized polypyrrole nanoparticles with controlled diameters were readily fabricated by the pyrolysis of polypyrrole nanoparticles. The carbonized polypyrrole nanoparticles showed narrow size distribution, large micropore volume, and high surface area. Magnetic phases were introduced into the carbon nanoparticles during the pyrolysis without sophisticated process, which resulted in useful magnetic properties for selective nanoparticle separation. Field emission scanning electron microscopy, Raman spectrometer, N(2) adsorption/desorption, X-ray diffraction, and superconducting interference device were employed for cha...
Source: Biomaterials - October 28, 2009 Category: Materials Science Authors: Oh WK, Yoon H, Jang J Tags: Biomaterials Source Type: journals

Structure-activity relationships of cationic shell-crosslinked knedel-like nanoparticles: Shell composition and transfection efficiency/cytotoxicity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cationic nanoparticles are a promising class of transfection agents for oligonucleotide and gene delivery, but vary greatly in their effectiveness and cytotoxicity. Recently, we developed a new class of cationic transfection agents based on cationic shell-crosslinked knedel-like nanoparticles (cSCKs) that efficiently transfect mammalian cells with both oligonucleotides and plasmid DNA. In an effort to further improve transfection efficiency without increasing cytotoxicity, we examined the effects of the composition of primary amine (pa), tertiary amine (ta) and carboxylic acid (ca) groups in the shell of these nanopart...
Source: Biomaterials - October 28, 2009 Category: Materials Science Authors: Zhang K, Fang H, Wang Z, Li Z, Taylor JS, Wooley KL Tags: Biomaterials Source Type: journals

The in vivo performance of magnetic particle-loaded injectable, in situ gelling, carriers for the delivery of local hyperthermia.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We investigated the use of in situ implant formation that incorporates superparamagnetic iron oxide nanoparticles (SPIONs) as a form of minimally invasive treatment of cancer lesions by magnetically induced local hyperthermia. We developed injectable formulations that form gels entrapping magnetic particles into a tumor. We used SPIONs embedded in silica microparticles to favor syringeability and incorporated the highest proportion possible to allow large heating capacities. Hydrogel, single-solvent organogel and cosolvent (low-toxicity hydrophilic solvent) organogel formulations were injected into human cancer tumors ...
Source: Biomaterials - October 28, 2009 Category: Materials Science Authors: Le Renard PE, Jordan O, Faes A, Petri-Fink A, Hofmann H, Rüfenacht D, Bosman F, Buchegger F, Doelker E Tags: Biomaterials Source Type: journals

Polyethylenimine-PEG coated albumin nanoparticles for BMP-2 delivery.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we report a nanoparticulate (NP) system for BMP-2 delivery based on bovine serum albumin (BSA) NPs stabilized with a poly(ethylene glycol) modified polyethylenimine (PEI-PEG) coating. PEI-PEG with different PEG substitutions were synthesized, and the cell viability assay showed PEG substitution greatly reduced the cytotoxicity of the native PEI. Furthermore, PEI-PEG coated BSA NPs demonstrated smaller size and decreased zeta potential compared to PEI-coated NPs. The bioactivity of the encapsulated BMP-2 and the toxicity of PEI-PEG coated NPs were examined by the alkaline phosphatase (ALP) induction assay and...
Source: Biomaterials - October 28, 2009 Category: Materials Science Authors: Zhang S, Kucharski C, Doschak MR, Sebald W, Uludağ H Tags: Biomaterials Source Type: journals

The mechanically enhanced phase separation of sprayed polyurethane scaffolds and their effect on the alignment of fibroblasts.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This paper reports a method to fabricate anisotropic scaffolds of tunable porosity and mechanical properties. Scaffolds were fabricated using a computer controlled sprayed phase separation technique. Following fabrication, the sheets were elongated 0, 35 or 70% of their original length to induce varying degrees of scaffold alignment and anisotropy. The nonsolvent used in the phase separation was shown to affect porosity and the elastic modulus. Mouse embryo NIH-3T3 fibroblasts were cultured on the scaffolds to investigate cell response to the anisotropy of the scaffold. A 2D FFT method was used to quantify cellular ali...
Source: Biomaterials - October 28, 2009 Category: Materials Science Authors: Kennedy JP, McCandless SP, Lasher RA, Hitchcock RW Tags: Biomaterials Source Type: journals

Hydrodynamic spinning of hydrogel fibers.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Hydrogel scaffolds are highly hydrated polymer networks that allow cells to adhere, proliferate and differentiate in the treatment of diseased or injured tissues and organs. Using hydrodynamic shaping and in situ cross-linking of hydrogel precursors, we have developed a highly efficient "hydrodynamic spinning" approach for synthesizing hydrogel fibers of different diameters in a multiphase coaxial flow. A triple-orifice spinneret has been created, and three different types of hydrogel precursors have been examined. Without changing the spinning head, hollow and solid hydrogel fibers with different diameters have been s...
Source: Biomaterials - October 28, 2009 Category: Materials Science Authors: Hu M, Deng R, Schumacher KM, Kurisawa M, Ye H, Purnamawati K, Ying JY Tags: Biomaterials Source Type: journals

Fatigue-life assessment and validation techniques for metallic vascular implants.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Vascular implants, such as cardiac valve prostheses, stents, and other devices are often subjected to complex loading conditions in vivo, which can include pulsatile pressure cycling, bending, torsion, tension, and compression, among others. At an average of 72 heartbeats per minute, pulsatile loading alone produces approximately 40-million cycles per year. With design lives of 10-15 years, fatigue performance assessment and validation of these devices are critical for the designer, as mechanical failure can have serious consequences. Historically, various fatigue life assessment approaches have been used to validate e...
Source: Biomaterials - October 27, 2009 Category: Materials Science Authors: James BA, Sire RA Tags: Biomaterials Source Type: journals

The Adherence of platelets to adsorbed albumin by receptor-mediated recognition of binding sites exposed by adsorption-induced unfolding.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Although albumin (Alb) is the most abundant plasma protein, it is considered to be non-adhesive to platelets, as it lacks any known amino acid sequences for binding platelet receptors. Recent studies have suggested that platelets adhere to adsorbed Alb by mechanisms linked to its conformational state. To definitively address this issue we used circular dichroism (CD) spectropolarimetry to characterize the conformation of Alb adsorbed on a broad range of surface chemistries from a wide range of Alb solution concentrations, with platelet adhesion examined using a lactate dehydrogenase (LDH) assay and scanning electron mi...
Source: Biomaterials - October 26, 2009 Category: Materials Science Authors: Sivaraman B, Latour RA Tags: Biomaterials Source Type: journals

Biological responses to hydroxyapatite surfaces deposited via a co-incident microblasting technique.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study two methods for creating a HA layer on metal alloys that employ micro-blasting have been evaluated to determine if the inclusion of an abrasive agent can enhance the in vitro and in vivo performance of the modified surface. The first method employs direct micro-blasting using HA as the abrasive media, while the second employs a simultaneous blasting with an alumina abrasive and coincident blasting with HA as a dopant. Whereas, both methods were found to produce a surface which was enriched with HA, the respective microstructures created were significantly different. Detailed surface characterisation revealed ...
Source: Biomaterials - October 26, 2009 Category: Materials Science Authors: O'Hare P, Meenan BJ, Burke GA, Byrne G, Dowling D, Hunt JA Tags: Biomaterials Source Type: journals

Surfaces modified with nanometer-thick silver-impregnated polymeric films that kill bacteria but support growth of mammalian cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Silver is widely used as a biocidal agent in ointments and wound dressings. However, it has also been associated with tissue toxicity and impaired healing. In vitro characterization has also revealed that typical loadings of silver employed in ointments and dressings ( approximately 100mug/cm(2)) lead to cytotoxicity. In this paper, we report the results of an initial study that sought to determine if localization of carefully controlled loadings of silver nanoparticles within molecularly thin films immobilized on surfaces can lead to antimicrobial activity without inducing cytotoxicity. Polymeric thin films of poly(al...
Source: Biomaterials - October 26, 2009 Category: Materials Science Authors: Agarwal A, Weis TL, Schurr MJ, Faith NG, Czuprynski CJ, McAnulty JF, Murphy CJ, Abbott NL Tags: Biomaterials Source Type: journals

Osteogenic differentiation of human amniotic fluid-derived stem cells induced by bone morphogenetic protein-7 and enhanced by nanofibrous scaffolds.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Amniotic fluid-derived stem cells (AFSCs) are becoming an important source of cells for regenerative medicine given their apparent advantages of accessibility, renewal capacity and multipotentiality. In the intermediate stage between the embryonic stem cells (ESCs) and adult stem cells, AFSCs may have a distinct mechanism to choose their fate. Unfortunately, until now, little is known about how bone morphogenetic proteins (BMPs) control the osteoblastic differentiation of AFSCs, especially on 3D scaffolds. Our research shows that human AFSCs (hAFSCs) can be induced for osteoblastic differentiation by rhBMP-7, and hAFSC...
Source: Biomaterials - October 24, 2009 Category: Materials Science Authors: Sun H, Feng K, Hu J, Soker S, Atala A, Ma PX Tags: Biomaterials Source Type: journals

Toxicological characteristics of nanoparticulate anatase titanium dioxide in mice.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In an effort to examine liver injury, immune response, and other physiological effects in mice caused by intragastric administration of nanoparticulate anatase titanium dioxide (5nm), we assessed T lymphocytes, B lymphocyte and NK lymphocyte counts, hematological indices, biochemical parameters of liver functions, and histopathological changes in nanoparticulate titanium dioxide -treated mice. Indeed, mice treated with higher dose nanoparticulate titanium dioxide displayed a reduction in body weight, an increase in coefficients of the liver and histopathological changes in the liver. Specifically, in these nanoparticul...
Source: Biomaterials - October 24, 2009 Category: Materials Science Authors: Duan Y, Liu J, Ma L, Li N, Liu H, Wang J, Zheng L, Liu C, Wang X, Zhao X, Yan J, Wang S, Wang H, Zhang X, Hong F Tags: Biomaterials Source Type: journals

Nanoscale protein-based memory device composed of recombinant azurin.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this present study, a nanoscale protein-based memory device consisting of recombinant azurin with its cysteine residues modified by site-directed mutagenesis method has been developed. Cysteine residues were modified to directly coordinate with the gold surface without use of any chemical linkers. Cyclic voltammetry (CV) method was used to measure the redox behavior of the immobilized azurin. Open-circuit potential amperometry (OCPA) technique allowed observing the memory characteristics including "write", "erase" and "read" functions of a nanoscale memory device. The variations in topology and the electron transfer...
Source: Biomaterials - October 24, 2009 Category: Materials Science Authors: Kim SU, Yagati AK, Min J, Choi JW Tags: Biomaterials Source Type: journals

Molecular design of chitosan gene delivery systems with an optimized balance between polyplex stability and polyplex unpacking.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Chitosan is an attractive gene delivery vehicle, but the criteria and strategies for the design of efficient chitosan gene delivery systems remain unclear. The purpose of this work was to investigate how the strength of the charge-based interaction between chitosan and DNA determines the gene expression levels and to design chitosan vectors with an optimized balance between polyplex stability and polyplex unpacking. Using 21 formulations based on low molecular weight chitosans with constant charge density and a number-average degree of polymerization (DPn) in the range of 21-88 (M(w) 4.7-33kDa), we studied the relation...
Source: Biomaterials - October 24, 2009 Category: Materials Science Authors: Strand SP, Lelu S, Reitan NK, de Lange Davies C, Artursson P, Vårum KM Tags: Biomaterials Source Type: journals

The influence of rat mesenchymal stem cell CD44 surface markers on cell growth, fibronectin expression, and cardiomyogenic differentiation on silk fibroin - Hyaluronic acid cardiac patches.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Since MSCs contain an abundant of CD44 surface markers, it is of interesting to investigate whether CD44 on rat MSC (rMSCs) influenced cell growth, fibronectin expression and cardiomyogenic differentiation on new SF/HA cardiac patches. For this investigation, we examined the influences of rMSCs with or without a CD44-blockage treatment on the aforementioned issues after they were cultivated, and further induced by 5-aza on SF and SF/HA patches. The results showed that the relative growth rates of rMSCs cultured on cultural wells, SF/HA patches without or with a CD44-blockage treatment were 100%, 208.9+/-7.1 (%) or 48.4...
Source: Biomaterials - October 24, 2009 Category: Materials Science Authors: Yang MC, Chi NH, Chou NK, Huang YY, Chung TW, Chang YL, Liu HC, Shieh MJ, Wang SS Tags: Biomaterials Source Type: journals

Neuronal cell growth on iridium oxide.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study the biocompatibility of pure iridium and different iridium oxides that differ characteristically in their surface roughness was investigated using two different biological test systems, insect and vertebrate neurons. Iridium oxide surfaces were coated with Concanavalin A and poly-(d)-lysine. In detailed investigations (R(a) value determination, contact angle measurement, marker enzyme assay) the surface characteristics of non-modified and coated iridium oxide films were analysed, demonstrating that the materials can be successfully coated. Furthermore, we show that locust neurons grow well on all substrates t...
Source: Biomaterials - October 24, 2009 Category: Materials Science Authors: Göbbels K, Kuenzel T, van Ooyen A, Baumgartner W, Schnakenberg U, Bräunig P Tags: Biomaterials Source Type: journals

Pharmacological activity and protein phosphorylation caused by nitric oxide-releasing microparticles.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Nitric oxide (NO)-releasing microparticles were developed as a potential treatment option against various blood flow irregulations including sexual dysfunction, atherosclerosis and metal stent-induced restenosis. Polymeric microparticles containing diethylenetriamine diazeniumdiolate (DETA NONOate), a NO donor, were prepared using modified double-emulsion solvent evaporation method to maximize the loading efficacy and stability of DETA NONOate. The pharmacological effects of the NO-releasing microparticles were evaluated by examining the changes in the vaginal blood flow in rats. The effects of NO on the phosphorylatio...
Source: Biomaterials - October 24, 2009 Category: Materials Science Authors: Yoo JW, Choe ES, Ahn SM, Lee CH Tags: Biomaterials Source Type: journals