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2-D mapping of skin chromophores in the spectral range 500 - 700 nmEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The multi-spectral imaging technique has been used for distant mapping of in-vivo skin chromophores by analyzing spectral data at each reflected image pixel and constructing 2-D maps of the relative concentrations of oxy-/deoxy-haemoglobin and melanin. Instead of using a broad visible-NIR spectral range, this study focuses on narrowed spectral band 500-700 nm, speeding-up the signal processing procedure. Regression analysis confirmed that superposition of three Gaussians is optimal analytic approximation for the oxy-haemoglobin absorption tabular spectrum in this spectral band, while superposition of two Gaussians fits wel...
Source: Journal of Biophotonics - November 5, 2009 Category: Physics Authors: Dainis Jakovels, Janis Spigulis Source Type: journals

Cultured human keratinocytes for optical transmission measurementEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The challenges of measuring optical properties of human tissues include the thickness of the sample, homogenization, or crystallization from freezing of the tissue. This investigation demonstrates a method to avoid these problems by growing optically thin samples of human keratinocytes as a substitute for ex vivo epidermis samples. Several methods of growth were investigated. Resulting samples were measured on a spectrophotometer for transmission between 300 nm and 2600 nm. The efficacy of the cell growth was confirmed with histological examination of several cultured keratinocyte samples. Limitations were the requirement ...
Source: Journal of Biophotonics - October 19, 2009 Category: Physics Authors: David Schaaf, Thomas Eurell, Thomas Johnson Source Type: journals

Concurrent observations of astrocytic Ca2+ activity and multisite extracellular potentials from an intact cerebral cortexEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In basic neuroscience, the attention has been recently focused on the role played by the protoplasmic astrocytes in modulating the activity of nearby neurons or else on assisting a long-term/sustained communication between these neurons and the surrounding microvasculature. However, to understand the physiological mechanisms underlying such a multiscale interactions in space and time, novel methodologies are required. This paper reports about an experimental setting and a procedure that was developed to obtain concurrently two-photon astrocytic Ca2+ imaging and multisite large-scale extracellular potentials as recorded by ...
Source: Journal of Biophotonics - October 15, 2009 Category: Physics Authors: Jorge Riera, Takeshi Ogawa, Rieko Hatanaka, Takakuni Goto, Akira Sumiyoshi, Herve Enjieu Kadji, Sakura Nakauchi, Ryuta Kawashima Source Type: journals

Monitoring of glucose permeability in monkey skin in vivo using Optical Coherence TomographyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Topical trans-dermal delivery of drugs has proven to be a promising route for treatment of many dermatological diseases. The aim of this study is to monitor and quantify the permeability rate of glucose solutions in rhesus monkey skin noninvasively in vivo as a primate model for drug diffusion. A time-domain Optical Coherence Tomography (OCT) system was used to image the diffusion of glucose in the skin of anesthetized monkeys for which the permeability rate was calculated. From 5 experiments on 4 different monkeys, the permeability for glucose-20% was found to be (4.41 ± 0.28) 10-6 cm/sec. The results suggest that OCT mi...
Source: Journal of Biophotonics - October 12, 2009 Category: Physics Authors: Mohamad G. Ghosn, Narendran Sudheendran, Mark Wendt, Adrian Glasser, Valery V. Tuchin, Kirill V. Larin Source Type: journals

The potential of biophotonic techniques in stem cell tracking and monitoring of tissue regeneration applied to cardiac stem cell therapyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The use of injected stem cells, leading to regeneration of ischemic heart tissue, for example, following coronary artery occlusion, has emerged as a major new option for managing 'heart attack' patients. While some clinical trials have been encouraging, there have also been failures and there is little understanding of the multiplicity of factors that lead to the outcome. In this overview paper, the opportunities and challenges in applying biophotonic techniques to regenerative medicine, exemplified by the challenge of stem cell therapy of ischemic heart disease, are considered. The focus is on optical imaging to track ste...
Source: Journal of Biophotonics - September 28, 2009 Category: Physics Authors: Brian C. Wilson, I. Alex Vitkin, Dennis L. Matthews Source Type: journals

A fluorescence lifetime imaging scanning confocal endomicroscopeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We describe a fluorescence lifetime imaging endomicroscope employing a fibre bundle probe and time correlated single photon counting. Preliminary images of stained pollen grains, eGFP-labelled cells exhibiting Förster resonant energy transfer and tissue autofluorescence are presented. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) (Source: Journal of Biophotonics)
Source: Journal of Biophotonics - September 27, 2009 Category: Physics Authors: Gordon T. Kennedy, Hugh B. Manning, Daniel S. Elson, Mark A. A. Neil, Gordon W. Stamp, Bertrand Viellerobe, François Lacombe, Chris Dunsby, Paul M. W. French Source Type: journals

Scoring of collagen organization in healthy and diseased human dermis by multiphoton microscopyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We have used nonlinear imaging to evaluate collagen organization in connective tissue ex-vivo samples. Image analysis methods were tested on healthy dermis, normal scars, and keloids. The evaluation of the second harmonic to autofluorescence aging index of dermis (SAAID) has allowed a first characterization of tissues by scoring the collagen/elastin content. Further analyses on collagen morphology in healthy dermis and keloids were performed by image-pattern analysis of SHG images. The gray-level co-occurrence matrix (GLCM) analysis method has allowed classification of different tissues based on the evaluation of geometric...
Source: Journal of Biophotonics - September 21, 2009 Category: Physics Authors: Riccardo Cicchi, Dimitrios Kapsokalyvas, Vincenzo De Giorgi, Vincenza Maio, Annelies Van Wiechen, Daniela Massi, Torello Lotti, Francesco S. Pavone Source Type: journals

Quantified characterization of human cutaneous normal scar using multiphoton microscopyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The morphological alterations of human cutaneous normal scar were quantitatively analyzed using multiphoton microscopy (MPM) based on two-photon excited fluorescence and second harmonic generation. High-contrast, high-resolution images of normal scar and uninjured skin were obtained for comparison. In addition, some quantitative parameters have been extracted to quantitatively discriminate between normal scar and uninjured skin. The MPM combined with quantitative method enable a better understanding of microstructual alterations of the epidermis, elastic fiber, and collagen in normal scar. It may lead the way to making kno...
Source: Journal of Biophotonics - September 18, 2009 Category: Physics Authors: Xiaoqin Zhu, Shuangmu Zhuo, Liqin Zheng, Kecheng Lu, Xingshan Jiang, Jianxin Chen, Bifang Lin Source Type: journals

Characterization of vascular structures and skin bruises using hyperspectral imaging, image analysis and diffusion theoryEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Hyperspectral imaging, image analysis and diffusion theory were used to visualize skin vasculature and to monitor the development of fresh skin bruises. Bruises were inflicted in a porcine model, and the development of the hemorrhage was monitored using white light hyperspectral imaging (400-1000 nm). Hyperspectral images from human volunteers were also included in the study. Statistical image analysis was used to classify bruised regions and to visualize the skin vasculature. Biopsies were collected from the animals to reveal the true depth of the bruising. A three-layer diffusion model and an analytic hemoglobin transpor...
Source: Journal of Biophotonics - September 8, 2009 Category: Physics Authors: Lise Lyngsnes Randeberg, Eivind La Puebla Larsen, Lars Othar Svaasand Source Type: journals

Tissue viability (TiVi) imaging: temporal effects of local occlusion studies in the volar forearmEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Tissue Viability (TiVi) imaging is a promising new technology for the assessment of microcirculation in the upper human dermis. Although the technique is easily implemented and develops large amounts of observational data, its role in the clinical workplace awaits the development of standardised protocols required for routine clinical practice. The present study investigates the use of TiVi technology in a human, in vivo, localized, skin blood flow occlusion protocol. In this feasibility study, the response of the cutaneous microcirculation after provocation on the volar surface of the forearm was evaluated using a high te...
Source: Journal of Biophotonics - August 28, 2009 Category: Physics Authors: Paul M. McNamara, Jim O'Doherty, Marie-Louise O'Connell, Barry W. Fitzgerald, Chris D. Anderson, Gert E. Nilsson, Rani Toll, Martin J. Leahy Source Type: journals

Imaging of tumor vasculature using Twente photoacoustic systemsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Photoacoustic imaging is a hybrid imaging modality based on the detection of acoustic waves generated by the absorption of short laser pulses in biological tissue. It combines the advantages of excellent contrast achieved in optical techniques with the high resolution of ultrasound imaging. In this article we present a review of the work done at the University of Twente to image tumor angiogenesis in vivo using this technique. We start with a description and the technical details of the different photoacoustic systems developed in our laboratory, with their validation on phantoms. We then discuss small-animal studies with ...
Source: Journal of Biophotonics - August 27, 2009 Category: Physics Authors: Jithin Jose, Srirang Manohar, Roy G. M. Kolkman, W. Steenbergen, Ton G. van Leeuwen Source Type: journals

Optical manipulation for single-cell studiesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In the last decade optical manipulation has evolved from a field of interest for physicists to a versatile tool widely used within life sciences. This has been made possible in particular due to the development of a large variety of imaging techniques that allow detailed information to be gained from investigations of single cells. The use of multiple optical traps has high potential within single-cell analysis since parallel measurements provide good statistics. Multifunctional optical tweezers are, for instance, used to study cell heterogeneity in an ensemble, and force measurements are used to investigate the mechanical...
Source: Journal of Biophotonics - August 27, 2009 Category: Physics Authors: Kerstin Ramser, Dag Hanstorp Source Type: journals

Automated laser guidance of neuronal growth cones using a spatial light modulatorEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The growth cone of a developing neuron can be guided using a focused infra-red (IR) laser beam [1]. In previous setups this process has required a significant amount of user intervention to adjust continuously the laser beam to guide the growing neuron. Previously, a system using an acousto-optical deflector (AOD) has been developed to steer the beam [2]. However, to enhance the controllability of this system, here we demonstrate the use of a computer controlled spatial light modulator (SLM) to steer and manipulate the shape of a laser beam for use in guided neuronal growth. This new experimental setup paves the way to ena...
Source: Journal of Biophotonics - August 24, 2009 Category: Physics Authors: David J. Carnegie, Tomá[scaron] [Ccaron]i[zcaron]már, Jörg Baumgartl, Frank J. Gunn-Moore, Kishan Dholakia Source Type: journals

A two-photon europium complex as specific endoplasmic reticulum probeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Highly emissive europium complexes with specific endoplasmic reticulum localization potential includes several advantages such as fast uptake, long resident lifetime, low dosage requirement, low cytotoxicity and highly emissive two-photon induced f-f emission imaging. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) (Source: Journal of Biophotonics)
Source: Journal of Biophotonics - August 13, 2009 Category: Physics Authors: Ga-Lai Law, Ka-Leung Wong, Cornelia Wing-Yin Man, Sai-Wah Tsao, Wing-Tak Wong Source Type: journals

Resonance Raman spectroscopy as an effective tool for the determination of antioxidative stability of cosmetic formulationsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Carotenoids beta-carotene, lutein, lycopene and others are well-known powerful antioxidants acting as an effective neutralizer of free radicals produced in the human organism as a result of the influence of stress factors, such as UV irradiation. The protective effect of antioxidants is used in cosmetic products to increase the skin protection against the destructive action of free radicals and for the stabilization of formulations against oxidation. In the skin, the different antioxidant substances form protection chains to avoid their destruction by the interaction with the free radicals. Similar effects have to be expec...
Source: Journal of Biophotonics - August 13, 2009 Category: Physics Authors: Maxim E. Darvin, Wolfram Sterry, Jürgen Lademann Source Type: journals

Imaging engineered tissues using structural and functional optical coherence tomographyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
As the field of tissue engineering evolves, there will be an increasingly important need to visualize and track the complex dynamic changes that occur within three-dimensional constructs. Optical coherence tomography (OCT), as an emerging imaging technology applied to biological materials, offers a number of significant advantages to visualize these changes. Structural OCT has been used to investigate the longitudinal development of engineered tissues and cell dynamics such as migration, proliferation, detachment, and cell-material interactions. Optical techniques that image functional parameters or integrate multiple imag...
Source: Journal of Biophotonics - August 10, 2009 Category: Physics Authors: Xing Liang, Benedikt W. Graf, Stephen A. Boppart Source Type: journals

Quantification of Mucosa oxygenation using three discrete spectral bands of visible lightEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Quantification of the mucosa oxygenation levels during Endoscopic imaging provides useful physiological/diagnostic information. In this work a method for non-contact quantification of the oxygen saturation index during Endoscopic imaging using three discrete spectral-band in the blue, the green, and the red parts of the spectrum (RGB bands) has been investigated. The oxygen saturation index (TOI_rgb) was calculated from the three discrete RGB spectral bands using diffusion approximation modeling and least-square analysis. A parametric study performed to identify the optimum band width for each of the three spectral bands. ...
Source: Journal of Biophotonics - August 10, 2009 Category: Physics Authors: Y. Fawzy Source Type: journals

Clinical applications of slide-based cytometry - an updateEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Slide-based cytometric approaches open the possibility to obtain quantitative and objective data from specimens that so far have not been accessible to this kind of analysis. In this review, we will highlight the specific advantages of slide-based cytometry (SBC) and show the applications that have been established for clinical samples. Focuses are cytomic analyses of oncological and hematological samples where the slide-based concept turned out to open new dimensions in understanding underlying cellular networks. We review the recent literature and point out future applications. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, ...
Source: Journal of Biophotonics - August 9, 2009 Category: Physics Authors: Andreas O. H. Gerstner, Wiebke Laffers, Attila Tárnok Source Type: journals

Flow cytometry with gold nanoparticles and their clusters as scattering contrast agents: FDTD simulation of light-cell interactionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The formulation of the finite-difference time-domain (FDTD) approach is presented in the framework of its potential applications to in-vivo flow cytometry based on light scattering. The consideration is focused on comparison of light scattering by a single biological cell alone in controlled refractive-index matching conditions and by cells labeled by gold nanoparticles. The optical schematics including phase contrast (OPCM) microscopy as a prospective modality for in-vivo flow cytometry is also analyzed. The validation of the FDTD approach for the simulation of flow cytometry may open up a new avenue in the development of...
Source: Journal of Biophotonics - August 9, 2009 Category: Physics Authors: Stoyan Tanev, Wenbo Sun, James Pond, Valery V. Tuchin, Vladimir P. Zharov Source Type: journals

Intracellular imaging of host-pathogen interactions using combined CARS and two-photon fluorescence microscopiesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Intracellular imaging is a key tool in the investigation of host-pathogen interactions. Advances in this area are particularly sought to understand the effect of viral infection processes on the host cell and its metabolic functions including those cases where host cell lipid metabolism is modulated as a result of infection. We demonstrate the use of combined coherent anti-Stokes Raman scattering (CARS) and two-photon fluorescence microscopies to image fibroblast cells infected by cytomegalovirus. CARS is used to image the host cell membrane, lipid droplets and morphology of the nucleus. Cell nuclei are found to expand dur...
Source: Journal of Biophotonics - August 6, 2009 Category: Physics Authors: Iain Robinson, Michael Andreas Ochsenkühn, Colin J. Campbell, Gerard Giraud, William J. Hossack, Jochen Arlt, Jason Crain Source Type: journals

Label-free biochemical characterization of stem cells using vibrational spectroscopyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This article reviews recent developments in applying these techniques for the characterization of stem cells. A discussion of the potential for these methods to address some of the major challenges in stem cell research is presented, as well as the technological and scientific advancements that are needed to progress the knowledge in the field. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) (Source: Journal of Biophotonics)
Source: Journal of Biophotonics - August 2, 2009 Category: Physics Authors: James W. Chan, Deborah K. Lieu Source Type: journals

The metabolic component of cellular refractivity and its importance for optical cytometryEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Initially, it has been shown that the phase thickness and refractivity (the latter interpreted as the difference of the refractivity indices of an object and surrounding milieu) depend on the functional state of mitochondria. The refractivity of various objects decreased in response to energy depletion. This dependence was then demonstrated for other biological objects such as cyanobacteria, chloroplasts and human cells. This general response brought about the hypothesis of a certain "universal" factor that links the variable (or metabolic) component of refractivity with the object's functional state. However, the origin o...
Source: Journal of Biophotonics - July 30, 2009 Category: Physics Authors: V. Tychinsky Source Type: journals

Surgical applications of femtosecond lasersEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Femtosecond laser ablation permits non-invasive surgeries in the bulk of a sample with submicrometer resolution. We briefly review the history of optical surgery techniques and the experimental background of femtosecond laser ablation. Next, we present several clinical applications, including dental surgery and eye surgery. We then summarize research applications, encompassing cell and tissue studies, research on C. elegans, and studies in zebrafish. We conclude by discussing future trends of femtosecond laser systems and some possible application directions. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) (Source: Jo...
Source: Journal of Biophotonics - July 14, 2009 Category: Physics Authors: Samuel H. Chung, Eric Mazur Source Type: journals

Targeted optical injection of gold nanoparticles into single mammalian cellsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present an all optical technique for the targeted delivery of single 100 nm diameter gold nanoparticles into a specified region of the interior of an individual mammalian cell through a combination of optical tweezing and optical injection. The internalisation of the nanoparticle is verified by confocal laser scanning microscopy and confocal laser scanning reflectance microscopy. This represents the first time that nano sized particles have been tweezed and optically injected into mammalian cells using only light, and provides a novel methodology for internalising nanosphere based biosensors within specific intracellula...
Source: Journal of Biophotonics - July 14, 2009 Category: Physics Authors: Craig McDougall, David J. Stevenson, Christian T. A. Brown, Frank Gunn-Moore, Kishan Dholakia Source Type: journals

Diffraction imaging of spheres and melanoma cells with a microscope objectiveEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Diffraction imaging of polystyrene spheres and B16F10 mouse melanoma cells embedded in gel has been investigated with a microscope objective. The diffraction images acquired with the objective from a sphere have been shown to be comparable to the Mie theory based projection images of the scattered light if the objective is translated to defocused positions towards the sphere. Using a confocal imaging based method to reconstruct and analyze the 3D structure, we demonstrated that genetic modifications in these cells can induce morphological changes and the modified cells can be used as an experimental model for study of the ...
Source: Journal of Biophotonics - July 10, 2009 Category: Physics Authors: Kenneth M. Jacobs, Li V. Yang, Junhua Ding, Andrew E. Ekpenyong, Reid Castellone, Jun Q. Lu, Xin-Hua Hu Source Type: journals

Investigation of multifocal choroiditis with panuveitis by three-dimensional high-penetration optical coherence tomographyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A single case of multifocal choroiditis with panuveitis (MFCPU) was investigated by a three-dimensional (3-D) high-penetration optical coherence tomography. The HP-OCT is based on a swept-source OCT technology, uses a probe beam with a center wavelength of 1060 nm, and possesses a depth resolution of 10.4 [mu] min tissue. Two eyes of an MFCPU patient were involved in this study. The eyes were also examined by color fundus photograph, fluorescein angiography (FA), and indocyanine green angiography (ICGA). Findings in these four modalities are comparatively discussed. The OCT scans revealed the following characteristic prope...
Source: Journal of Biophotonics - July 4, 2009 Category: Physics Authors: Yoshiaki Yasuno, Fumiki Okamoto, Keisuke Kawana, Toyohiko Yatagai, Tetsuro Oshika Source Type: journals

Optical coherence tomography and Raman spectroscopy of the ex-vivo retinaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We describe an OCT microscope for ex-vivo imaging combined with Raman spectroscopy capable of collecting morphological and molecular information about a sample simultaneously. We present our first results and discuss the challenges to further development of this dual-mode instrument and limitations for future in-vivo retinal imaging. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) (Source: Journal of Biophotonics)
Source: Journal of Biophotonics - June 29, 2009 Category: Physics Authors: Julia W. Evans, Robert J. Zawadzki, Rui Liu, James W. Chan, Stephen M. Lane, John S. Werner Source Type: journals

Recent developments in Fourier Domain Mode Locked lasers for optical coherence tomography: Imaging at 1310 nm vs. 1550 nm wavelengthEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report on recent progress in Fourier domain mode-locking (FDML) technology. The paper focuses on developments beyond pushing the speed of these laser sources. After an overview of improvements to FDML over the last three years, a brief analysis of OCT imaging using FDML lasers with different wavelengths is presented. For the first time, high speed, high quality FDML imaging at 1550 nm is presented and compared to a system at 1310 nm. The imaging results of human skin for both wavelengths are compared and analyzed. Sample arm optics, power on the sample, heterodyne gain, detection bandwidth, colour cut levels and sample ...
Source: Journal of Biophotonics - June 29, 2009 Category: Physics Authors: Benjamin R. Biedermann, Wolfgang Wieser, Christoph M. Eigenwillig, Robert Huber Source Type: journals

OCT imaging of skin cancer and other dermatological diseasesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Optical coherence tomography (OCT) provides clinicians and researchers with micrometer-resolution, in vivo, cross-sectional images of human skin up to several millimeter depth. This review of OCT imaging applied within dermatology covers the application of OCT to normal skin, and reports on a large number of applications in the fields of non-melanoma skin cancer, malignant melanomas, psoriasis and dermatitis, infestations, bullous skin diseases, tattoos, nails, haemangiomas, and other skin diseases. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) (Source: Journal of Biophotonics)
Source: Journal of Biophotonics - June 25, 2009 Category: Physics Authors: Mette Mogensen, Lars Thrane, Thomas M. Jørgensen, Peter E. Andersen, Gregor B. E. Jemec Source Type: journals

AM-FM techniques in the analysis of optical coherence tomography signalsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The subtle tissue changes associated with the early stages of malignancies, such as cancer, are not clearly discernible even at the current, improved, resolution of optical coherence tomography (OCT) systems. However, these changes directly affect the spectral content of the OCT image that contains information regarding these unresolvable features. Spectral analysis of OCT signals has recently been shown to provide additional information, resulting in improved contrast, directly related to scatterer size changes. Amplitude modulation-frequency modulation (AM-FM) analysis, a fast and accurate technique for the estimation of...
Source: Journal of Biophotonics - June 24, 2009 Category: Physics Authors: Costas Pitris, Andreas Kartakoullis, Evgenia Bousi Source Type: journals

A concentric three element radial scanning optical coherence tomography endoscopeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We have developed a 2.1 mm outer diameter optical coherence tomography endoscope that provides radial scans of luminal structures. The endoscope consists of three elements: (1) a stationary central core containing the fibers and focusing elements, (2) a rotating intermediate tube with a distal rod prism, and (3) a stationary sterilized glass cover. This design enables radial and spiral scanning and allows adjustment of the axial focal distance. Additionally, this design is capable of focusing light from multiple fibers into tissue. The performance of the endoscope was demonstrated in a study of tissue engineered blood vess...
Source: Journal of Biophotonics - June 15, 2009 Category: Physics Authors: Garret T. Bonnema, Kristen O. Cardinal, Stuart K. Williams, Jennifer K. Barton Source Type: journals

Doppler calibration method for Spectral Domain OCT spectrometersEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present a calibration method for SD-OCT domain spectrometers based on the M-scan of a moving mirror. This method allows determination of the wavenumber sampling increment which determines the depth axis assigned to the structural image. It also allows wavelength calibration of individual pixels which ensures correct re-sampling prior to Fast Fourier Transform. Determination of the spectrometer resolution, which determines sensitivity and resolution decay with depth, is also possible. The wavelength calibration results suggest that hardware calibration of the spectrometers is a necessary complement to the computational m...
Source: Journal of Biophotonics - June 15, 2009 Category: Physics Authors: Dirk J. Faber, Ton G. van Leeuwen Source Type: journals

Histogram-based filtering for quantitative 3D retinal angiographyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Doppler Fourier domain optical coherence tomography (D-FDOCT) can be used to visualise and measure ocular blood flow in the retina of the human eye. This has the potential to diagnose illnesses such as macula degeneration or diabetic retinopathy early on because these medical conditions cause a pathological change in the retinal vasculature and perfusion. Here we are presenting a method to separate quantitative blood flow information from static tissue. Our approach is demonstrated on retinal D-FDOCT volume scans taken at the optic nerve head (see figure) and near the fovea with a high speed CMOS-based FDOCT system. The ad...
Source: Journal of Biophotonics - June 11, 2009 Category: Physics Authors: Christoph Kolbitsch, Tilman Schmoll, Rainer A. Leitgeb Source Type: journals

Measurements of depolarization distribution in the healthy human macula by polarization sensitive OCTEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Polarization sensitive optical coherence tomography (PS-OCT) allows for depth resolved imaging of polarization properties of retinal structures. Different layers in the retina can be distinguished not only based on their reflectivity but also due to their birefringent, depolarizing or polarization preserving character. In contrast to other structures in the posterior segment, the retinal pigment epithelium (RPE) is depolarizing, i.e., it scrambles the polarization state of light. A spectral domain (SD) PS-OCT system was used to record 3D data sets of the retina. The depolarizing effect of the RPE was analyzed by quantitati...
Source: Journal of Biophotonics - June 11, 2009 Category: Physics Authors: Bernhard Baumann, Erich Götzinger, Michael Pircher, Christoph K. Hitzenberger Source Type: journals

Plasmonic nanoprobes for SERS biosensing and bioimagingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This article provides an overview of the development and application of plasmonic nanoprobes developed in our laboratory for biosensing and bioimaging. We describe the use of plasmonics surface-enhanced Raman scattering (SERS) gene probes for the detection of diseases using DNA hybridization to target biospecies (HIV gene, breast cancer genes etc.). For molecular imaging, we describe a hyperspectral surface-enhanced Raman imaging (HSERI) system that combines imaging capabilities with SERS detection to identify cellular components using Raman dye-labeled silver nanoparticles in cellular systems The detection of specific tar...
Source: Journal of Biophotonics - June 9, 2009 Category: Physics Authors: Tuan Vo-Dinh, Hsin-Neng Wang, Jonathan Scaffidi Source Type: journals

Basics of standardization and calibration in cytometry - a reviewEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Standardization, calibration, and controls (negative and positive controls) are essential for quality assurance. Cytometers are capable of reliable and repeatable cellular analyses. However, a prerequisite is instrument calibration and standardized preanalytics. Calibration is often done by beads. Beads are available for different quality control applications, e.g. calibration of size and measuring scale, compensation, absolute cell counting, and laser alignment. Results can be standardized by converting MFI values into MESF or ABC values. Standardized data allow comparison of experiments over a long period of time and bet...
Source: Journal of Biophotonics - June 5, 2009 Category: Physics Authors: Anja Mittag, Attila Tarnok Source Type: journals

Selective targeting of green fluorescent nanodiamond conjugates to mitochondria in HeLa cellsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Fluorescent cellular biomarkers play a prominent role in biosciences. Most of the available biomarkers have some drawbacks due to either physical and optical or cytotoxic properties. In view of this, we investigated the potential of green fluorescent nanodiamonds as biomarkers in living cells. Nanodiamonds were functionalized by attaching antibodies that target intracellular structures such as actin filaments and mitochondria. Then, the nanodiamond conjugates were transfected into HeLa cells. Transfections were mediated by 4th-generation dendrimers, cationic liposomes and protamine sulfate. Using fluorescence microscopy, w...
Source: Journal of Biophotonics - June 5, 2009 Category: Physics Authors: Msaukiranji Mkandawire, Andrea Pohl, Tatiana Gubarevich, Victoria Lapina, Dietmar Appelhans, Gerhard Rödel, Wolfgang Pompe, Jürgen Schreiber, Jörg Opitz Source Type: journals

OCT technology development: Where are we now? A commercial perspectiveEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The field of optical coherence tomography (OCT) has grown enormously since its inception in 1991 at MIT, encompassing many areas of imaging research. Improvements in the optical technology used in OCT systems, and in the design of the OCT interferometers and probes, has resulted in steadily improving image quality and more practical probe designs. Successful commercial application of OCT occurred first in retina imaging, and many further applications now appear ripe for translation from the laboratory to the marketplace. In this paper, I review this translation process from a commercial perspective, and attempt to draw hel...
Source: Journal of Biophotonics - June 5, 2009 Category: Physics Authors: Jon Holmes Source Type: journals

Dual optical coherence tomography/fluorescence microscopy for monitoring of Drosophila melanogaster larval heartEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This article demonstrates a combined instrument of two imaging modalities to acquire information on cardiac function in larval Drosophila melanogaster: optical coherence tomography (OCT) and laser scanning fluorescence microscopy (LSFM). For this purpose, a dedicated imaging instrument able to sequentially provide cross-sectional OCT and C-scan LSFM images has been developed. With this dual-imaging system, the heart can be easily located and visualized within the specimen and the change of the heart shape in a cardiac cycle can be monitored. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) (Source: Journal of Biophotonics)
Source: Journal of Biophotonics - June 5, 2009 Category: Physics Authors: Adrian Bradu, Lisha Ma, James W. Bloor, Adrian Podoleanu Source Type: journals

Toward the integration of cytomics and medicineEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The integration of cytomics research and healthcare informatics will facilitate technology transfer and reduce medical costs. The CytometryML prototype of the Advanced Cytometry Standard (ACS) has the benefits of including microscopic image and flow list-mode data, being based on XML and thus is compatible with existing medical and scientific informatics standards, such as HL7, and employing a design based upon the Digital Imaging and Communications in Medicine (DICOM) standard. The reuse of the well tested DICOM model resulted in a great decrease in the design and documentation effort and increased probability of reliabil...
Source: Journal of Biophotonics - June 5, 2009 Category: Physics Authors: Robert C. Leif Source Type: journals

Three- and four-dimensional visualization of cell migration using optical coherence tomographyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conventionally, cell chemotaxis is studied on two-dimensional (2D) transparent surfaces, due to limitations in optical and image data-collection techniques. However, surfaces that more closely mimic the natural environment of cells are often opaque. Optical coherence tomography (OCT) is a noninvasive label-free imaging technique, which offers the potential to visualize moving cells on opaque surfaces and in three dimensions (3D). Here, we demonstrate that OCT is an effective means of time-lapse videomicroscopy of Dictyostelium cells undergoing 3D (2D+time) cell migration on nitrocellulose substrates and 4D (3D+time) chemot...
Source: Journal of Biophotonics - May 28, 2009 Category: Physics Authors: Sara M. Rey, Boris Pova[zcaron]ay, Bernd Hofer, Angelika Unterhuber, Boris Hermann, Adrian Harwood, Wolfgang Drexler Source Type: journals

Probing for local activity-related modulation of the infrared backscattering of the brain cortexEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The possibility to measure the metabolic activity of the brain cortex, with submillimeter spatial and subsecond temporal resolution, would open up enticing scenarios in addressing basic issues on the relation between different structural components of brain signal processing, and in providing an operational pathway to interaction with (dis)functional signal patterns. In the present article, we report the description of a simple system that allows the detection of the minute changes that occur in the optical backscattering of the cortex as a metabolic response to external stimuli. The simplicity of the system is compatible ...
Source: Journal of Biophotonics - April 30, 2009 Category: Physics Authors: Gabriele E. M. Biella, Stefano Trevisan, Mario E. Giardini Source Type: journals

Raman spectroscopy of DNA packaging in individual human sperm cells distinguishes normal from abnormal cellsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Healthy human males produce sperm cells of which about 25-40% have abnormal head shapes. Increases in the percentage of sperm exhibiting aberrant sperm head morphologies have been correlated with male infertility, and biochemical studies of pooled sperm have suggested that sperm with abnormal shape may contain DNA that has not been properly repackaged by protamine during spermatid development. We have used micro-Raman spectroscopy to obtain Raman spectra from individual human sperm cells and examined how differences in the Raman spectra of sperm chromatin correlate with cell shape. We show that Raman spectra of individual ...
Source: Journal of Biophotonics - April 18, 2009 Category: Physics Authors: Thomas Huser, Christine A. Orme, Christopher W. Hollars, Michele H. Corzett, Rod Balhorn Source Type: journals

Photonics-based In Vivo total hemoglobin monitoring and clinical relevanceEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Anemia is a serious disorder which, as a result of antiquated invasive blood testing, is undiagnosed in millions of people in the U.S. As a result of the clinical need, many technological solutions have been proposed to measure total blood hemoglobin, and thus diagnose anemia, noninvasively. Because hemoglobin is the strongest chromophore in tissue, spectroscopic methods have been the most prevalently investigated. Difficulties in extracting a quantitative estimation of hemoglobin based on tissue absorption include variability in the absorption spectra of hemoglobin derivatives, interference from other tissue chromophores,...
Source: Journal of Biophotonics - April 17, 2009 Category: Physics Authors: John McMurdy, Gregory Jay, Selim Suner, Gregory Crawford Source Type: journals

Polarized diffuse reflectance measurements on cancerous and noncancerous tissuesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report the measurement of polarization parameters (linear retardance, diattenuation and depolarization) of normal and malignant tissue from human oral cavity and breast over the spectral range 390 nm to 550 nm. These parameters were determined using the 3 × 3 Mueller matrix, the elements of which could be determined using linear polarization measurements only. The significant differences observed in the polarization parameters of the normal and malignant tissues appear to arise because of the changes in the collagen matrix in the two tissue types. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) (Source: Journal of Biophotonics)
Source: Journal of Biophotonics - March 29, 2009 Category: Physics Authors: Sandeep Manhas, Mahesh K. Swami, Hari S. Patel, Abha Uppal, Nirmalya Ghosh, Pradeep K. Gupta Source Type: journals

Circulation and distribution of gold nanoparticles and induced alterations of tissue morphology at intravenous particle deliveryEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report also preliminary data on the light microscopy and TEM histological examination that allows evaluation of the changes in biotissues after gold NPs treatment. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) (Source: Journal of Biophotonics)
Source: Journal of Biophotonics - March 22, 2009 Category: Physics Authors: Georgy S. Terentyuk, Galina N. Maslyakova, Leyla V. Suleymanova, Boris N. Khlebtsov, Boris Ya. Kogan, Garif G. Akchurin, Alexander V. Shantrocha, Irina L. Maksimova, Nicolai G. Khlebtsov, Valery V. Tuchin Source Type: journals

Label free optical sensor for Avidin based on single gold nanoparticles functionalized with aptamersEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Optical spectroscopy of a single gold nanoparticle, functionalized with an aptamer, is used to sense the specific binding of avidin. Herewith, the field of single noble metal nanoparticle biosensors is extended to the important field of aptamer based assays. The sensitivity of this initial, but not yet optimized apta-nano-sensor is in the range of 20 nM. Due to its nanoscopic size, this single nanoparticle based apta-sensor may be used in nanoscopic volumes such as in array type assays or even inside cells. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) (Source: Journal of Biophotonics)
Source: Journal of Biophotonics - March 13, 2009 Category: Physics Authors: Frank Jeyson Hernandez, Srujan Kumar Dondapati, V. Cengiz Ozalp, Alessandro Pinto, Ciara K. O'Sullivan, Thomas A. Klar, Ioannis Katakis Source Type: journals

Effect of plasmonic nanostructures and nanofilms on fluorescence resonance energy transferEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We investigate the effect of silver nanostructures and nanofilms on fluorescence resonance energy transfer (FRET). Thin layers of poly (vinyl alcohol) of 10 or 20 nm with homogenously distributed donor (Cy3) and acceptor (Cy5) molecules were coated on silver islands and continuous silver films. Several geometrical configurations were studied with multiple donor-acceptor (D-A) samples with various acceptor concentrations. The acceptor concentrations were adjusted to yield FRET efficiencies from about 10 to 92% on bare glass surfaces. Time-resolved fluorescence spectroscopy was used to determine the energy transfer efficienc...
Source: Journal of Biophotonics - March 13, 2009 Category: Physics Authors: Henryk Szmacinski, Krishanu Ray, Joseph R. Lakowicz Source Type: journals

An AC electrokinetic method for enhanced detection of DNA nanoparticlesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In biomedical research and diagnostics it is a challenge to isolate and detect low levels of nanoparticles and nanoscale biomarkers in blood and other biological samples. While highly sensitive epifluorescent microscope systems are available for ultra low level detection, the isolation of the specific entities from large sample volumes is often the bigger limitation. AC electrokinetic techniques like dielectrophoresis (DEP) offer an attractive mechanism for specifically concentrating nanoparticles into microscopic locations. Unfortunately, DEP requires significant sample dilution thus making the technology unsuitable for b...
Source: Journal of Biophotonics - March 13, 2009 Category: Physics Authors: Rajaram Krishnan, Michael J. Heller Source Type: journals

A comparative Raman and CARS imaging study of colon tissueEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
An experimental evaluation of the information content of two complimentary techniques, linear Raman and coherent anti-Stokes Raman scattering (CARS) microscopy, is presented. CARS is a nonlinear variant of Raman spectroscopy that enables rapid acquisition of images within seconds in combination with laser scanning microscopes. CARS images were recorded from thin colon tissue sections at 2850, 1660, 1450 and 1000 cm-1 and compared with Raman images. Raman images were obtained from univariate and multivariate (k-means clustering) methods, whereas all CARS images represent univariate results. Variances within tissue sections ...
Source: Journal of Biophotonics - March 12, 2009 Category: Physics Authors: Christoph Krafft, Anuradha A. Ramoji, Christiane Bielecki, Nadine Vogler, Tobias Meyer, Denis Akimov, Petra Rösch, Michael Schmitt, Benjamin Dietzek, Iver Petersen, Andreas Stallmach, Jürgen Popp Source Type: journals