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Biomedical optics

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https://www.readbyqxmd.com/read/28107743/high-sensitivity-four-layer-polymer-fiber-optic-evanescent-wave-sensor
#1
Xin Xin, Nianbing Zhong, Qiang Liao, Yanyan Cen, Ruohua Wu, Zhengkun Wang
We present a novel four-layer structure consisting of bottom, second, third, and surface layers in the sensing region, for a D-shaped step-index fiber-optic evanescent wave (FOEW) sensor. To reduce the background noise, the surface of the longitudinal section in the D-shaped region is coated with a light-absorbing film. We check the morphologies of the second and surface layers, examine the refractive indices (RIs) of the third and surface layers, and analyze the composition of the surface layer. We also investigate the effects of the thicknesses and RIs of the third and surface layers and the LA film on the light transmission and sensitivity of the FOEW sensors...
January 11, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28106200/bright-conjugated-polymer-nanoparticles-containing-a-biodegradable-shell-produced-at-high-yields-and-with-tuneable-optical-properties-by-a-scalable-microfluidic-device
#2
T F Abelha, T W Phillips, J H Bannock, A M Nightingale, C A Dreiss, E Kemal, L Urbano, J C deMello, M Green, L A Dailey
This study compares the performance of a microfluidic technique and a conventional bulk method to manufacture conjugated polymer nanoparticles (CPNs) embedded within a biodegradable poly(ethylene glycol) methyl ether-block-poly(lactide-co-glycolide) (PEG5K-PLGA55K) matrix. The influence of PEG5K-PLGA55K and conjugated polymers cyano-substituted poly(p-phenylene vinylene) (CN-PPV) and poly(9,9-dioctylfluorene-2,1,3-benzothiadiazole) (F8BT) on the physicochemical properties of the CPNs was also evaluated. Both techniques enabled CPN production with high end product yields (∼70-95%)...
January 20, 2017: Nanoscale
https://www.readbyqxmd.com/read/28101428/wide-field-and-highly-sensitive-angiography-based-on-optical-coherence-tomography-with-akinetic-swept-source
#3
Jingjiang Xu, Shaozhen Song, Wei Wei, Ruikang K Wang
Wide-field vascular visualization in bulk tissue that is of uneven surface is challenging due to the relatively short ranging distance and significant sensitivity fall-off for most current optical coherence tomography angiography (OCTA) systems. We report a long ranging and ultra-wide-field OCTA (UW-OCTA) system based on an akinetic swept laser. The narrow instantaneous linewidth of the swept source with its high phase stability, combined with high-speed detection in the system enable us to achieve long ranging (up to 46 mm) and almost negligible system sensitivity fall-off...
January 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28095685/amphiphilic-polymer-guided-plasmonic-assemblies-and-their-biomedical-applications
#4
Jibin Song, Gang Niu, Xiaoyuan Chen
Plasmonic nanostructures with unique physical and biological properties have attracted increased attention for potential biomedical applications. Polymers grafted on metal nanoparticle surface can be used as assembly regulating molecules to guide nanoparticles organize into ordered or hierarchical structures in solution, within condensed phases, or at interfaces. In this Topical Review, we will highlight recent efforts on self-assembly of gold nanoparticles coated with polymer brushes. How and what kind of polymer graft can be used to adjust nanoparticle interactions, to dictate interparticle orientation, and to determine assembled nanostructures will be discussed...
January 18, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28076883/in-vivo-feasibility-test-using-transparent-carbon-nanotube-coated-polydimethylsiloxane-sheet-at-brain-tissue-and-sciatic-nerve
#5
Caifeng Wang, Sangjin Oh, Hyun Ah Lee, Jieun Kang, Ki-Jae Jeong, Seon Woo Kang, Dae Youn Hwang, Jaebeom Lee
Carbon nanotubes (CNTs), with their unique and outstanding properties, such as strong mechanical strength and high electrical conductivity, have become very popular for the repair of tissues, particularly for those requiring electrical stimuli. Polydimethylsiloxane (PDMS)-based elastomers have been used in a wide range of biomedical applications because of their optical transparency, physiological inertness, blood compatibility, non-toxicity, and gas permeability. In present study, most of artificial nerve guidance conduits (ANGCs) are not transparent...
January 11, 2017: Journal of Biomedical Materials Research. Part A
https://www.readbyqxmd.com/read/28074643/ultra-photostable-mesoporous-silica-coated-gap-enhanced-raman-tags-gerts-for-high-speed-bioimaging
#6
Yuqing Zhang, Yuanyuan Qiu, Li Lin, Hongchen Gu, Zeyu Xiao, Jian Ye
Surface enhanced Raman scattering (SERS) tags can be utilized as optical labeling nanoprobes similar to fluorescent dyes and quantum dots for bioimaging with additional advantages of the fingerprint vibrational signal as a unique optical code and the ultra-narrow linewidth for multiplexing. However, the development of SERS imaging technique is much less well-established compared to fluorescence imaging mainly due to the speed limitation. An effective strategy to improve the SERS imaging speed and simultaneously maintain the photostability of SERS tags has been never reported to the best of our knowledge...
January 11, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28071899/near-ir-absorbing-gold-nanoframes-with-enhanced-physiological-stability-and-improved-biocompatibility-for-in-vivo-biomedical-applications
#7
Liying Wang, Yunching Chen, Hsin Yao Lin, Yung-Te Hou, Ling-Chu Yang, Aileen Y Sun, Jia-Yu Liu, Chien-Wen Chang, Dehui Wan
This paper describes the synthesis of near-infrared (NIR)-absorbing gold nanoframes (GNFs) and a systematic study comparing their physiological stability and biocompatibility with those of hollow Au-Ag nanoshells (GNSs), which have been used widely as photothermal agents in biomedical applications because of their localized surface plasmon resonance (LSPR) in the NIR region. The GNFs were synthesized in three steps: galvanic replacement, Au deposition, and Ag dealloying, using silver nanospheres (SNP) as the starting material...
January 10, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28067994/identification-of-morphological-and-biochemical-changes-in-keratin-8-18-knock-down-cells-using-raman-spectroscopy
#8
S P Singh, Hunain Alam, Crismita Dmello, Hitesh Mamgain, Milind M Vaidya, Ramachandra Rao Dasari, C Murali Krishna
Accurate understanding of cellular processes and responses to stimuli is of paramount importance in biomedical research and diagnosis. Raman spectroscopy (RS), a label-free and nondestructive spectroscopic method has the potential to serve as a novel 'theranostics' tool. Both fiber-optic and micro-Raman studies have demonstrated efficacy in diagnostics and therapeutic response monitoring. In the present study, we have evaluated the potential of micro-Raman spectroscopic maps in identifying changes induced by loss of K8/18 proteins in a tongue cancer cell line...
January 9, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28059149/volumetric-light-field-encryption-at-the-microscopic-scale
#9
Haoyu Li, Changliang Guo, Inbarasan Muniraj, Bryce C Schroeder, John T Sheridan, Shu Jia
We report a light-field based method that allows the optical encryption of three-dimensional (3D) volumetric information at the microscopic scale in a single 2D light-field image. The system consists of a microlens array and an array of random phase/amplitude masks. The method utilizes a wave optics model to account for the dominant diffraction effect at this new scale, and the system point-spread function (PSF) serves as the key for encryption and decryption. We successfully developed and demonstrated a deconvolution algorithm to retrieve both spatially multiplexed discrete data and continuous volumetric data from 2D light-field images...
January 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28053532/biomedical-photoacoustics-fundamentals-instrumentation-and-perspectives-on-nanomedicine
#10
Chunpeng Zou, Beibei Wu, Yanyan Dong, Zhangwei Song, Yaping Zhao, Xianwei Ni, Yan Yang, Zhe Liu
Photoacoustic imaging (PAI) is an integrated biomedical imaging modality which combines the advantages of acoustic deep penetration and optical high sensitivity. It can provide functional and structural images with satisfactory resolution and contrast which could provide abundant pathological information for disease-oriented diagnosis. Therefore, it has found vast applications so far and become a powerful tool of precision nanomedicine. However, the investigation of PAI-based imaging nanomaterials is still in its infancy...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28050974/modifying-optical-properties-of-reduced-graphene-oxide-with-controlled-ozone-and-thermal-treatment-in-aqueous-suspensions
#11
Md Tanvir Hasan, Brian J Senger, Price Mulford, Conor Ryan, Hung Doan, Zygmunt Gryczynski, Anton V Naumov
Graphene possesses a number of advantageous properties, however, does not exhibit optical emission, which limits its use in optoelectronics. Unlike graphene, its functional derivative, graphene oxide (GO) exhibits fluorescence emission throughout the visible. Here, we focus on controlled methods for tuning the optical properties of GO. We introduce ozone treatment of reduced graphene oxide (RGO) in order to controllably transform it from non-emissive graphene-like material into GO with a specific fluorescence emission response...
January 4, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28050902/erythrocyte-membrane-coated-upconversion-nanoparticles-with-minimal-protein-adsorption-for-enhanced-tumor-imaging
#12
Lang Rao, Qian-Fang Meng, Lin-Lin Bu, Bo Cai, Qinqin Huang, Zhi-Jun Sun, Wen-Feng Zhang, Andrew Li, Shi-Shang Guo, Wei Liu, Tza-Huei Wang, Xing-Zhong Zhao
Upconversion nanoparticles (UCNPs) with superior optical and chemical features have been broadly employed for in vivo cancer imaging. Generally, UCNPs are surface modified with ligands for cancer active targeting. However, nanoparticles in biological fluids are known to form a long-lived "protein corona", which covers the targeting ligands on nanoparticle surface and dramatically reduces the nanoparticle targeting capabilities. Here, for the first time, we demonstrated that by coating UCNPs with red blood cell (RBC) membranes, the resulting cell membrane-capped nanoparticles (RBC-UCNPs) adsorbed virtually no proteins when exposed to human plasma...
January 12, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28048528/we-h-206-01-photoacoustic-tomography-multiscale-imaging-from-organelles-to-patients-by-ultrasonically-beating-the-optical-diffusion-limit
#13
L Wang
: Lihong V. Wang: Photoacoustic tomography (PAT), combining non-ionizing optical and ultrasonic waves via the photoacoustic effect, provides in vivo multiscale functional, metabolic, and molecular imaging. Broad applications include imaging of the breast, brain, skin, esophagus, colon, vascular system, and lymphatic system in humans or animals. Light offers rich contrast but does not penetrate biological tissue in straight paths as x-rays do. Consequently, high-resolution pure optical imaging (e...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047878/th-ab-209-06-an-investigation-of-the-feasibility-of-malignant-lesion-detection-during-routine-breast-cancer-screening-using-a-prototype-acousto-optic-transmission-ultrasound-imaging-system
#14
J R Rosenfield, J S Sandhu, P J La Riviere
PURPOSE: To investigate the feasibility of malignant lesion detection during routine breast cancer screening using an acousto-optic (AO) transmission ultrasound imaging system, particularly in premenopausal women with high breast density. METHODS: A full-field, single-projection ultrasound imaging system was developed that uses a high-resolution AO detector to convert the acoustic intensity transmitted through the compressed breast into a visual image by virtue of the AO effect in nematic liquid crystals...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047869/we-h-206-02-recent-advances-in-multi-modality-molecular-imaging-of-small-animals
#15
B Tsui
: Lihong V. Wang: Photoacoustic tomography (PAT), combining non-ionizing optical and ultrasonic waves via the photoacoustic effect, provides in vivo multiscale functional, metabolic, and molecular imaging. Broad applications include imaging of the breast, brain, skin, esophagus, colon, vascular system, and lymphatic system in humans or animals. Light offers rich contrast but does not penetrate biological tissue in straight paths as x-rays do. Consequently, high-resolution pure optical imaging (e...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047205/we-h-206-03-promises-and-challenges-of-benchtop-x-ray-fluorescence-ct-xfct-for-quantitative-in-vivo-imaging
#16
S Cho
: Lihong V. Wang: Photoacoustic tomography (PAT), combining non-ionizing optical and ultrasonic waves via the photoacoustic effect, provides in vivo multiscale functional, metabolic, and molecular imaging. Broad applications include imaging of the breast, brain, skin, esophagus, colon, vascular system, and lymphatic system in humans or animals. Light offers rich contrast but does not penetrate biological tissue in straight paths as x-rays do. Consequently, high-resolution pure optical imaging (e...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046461/we-h-206-00-advances-in-preclinical-imaging
#17
Patrick La Riviere
: Lihong V. Wang: Photoacoustic tomography (PAT), combining non-ionizing optical and ultrasonic waves via the photoacoustic effect, provides in vivo multiscale functional, metabolic, and molecular imaging. Broad applications include imaging of the breast, brain, skin, esophagus, colon, vascular system, and lymphatic system in humans or animals. Light offers rich contrast but does not penetrate biological tissue in straight paths as x-rays do. Consequently, high-resolution pure optical imaging (e...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28040957/distortion-correction-and-cross-talk-compensation-algorithm-for-use-with-an-imaging-spectrometer-based-spatially-resolved-diffuse-reflectance-system
#18
Derek J Cappon, Thomas J Farrell, Qiyin Fang, Joseph E Hayward
Optical spectroscopy of human tissue has been widely applied within the field of biomedical optics to allow rapid, in vivo characterization and analysis of the tissue. When designing an instrument of this type, an imaging spectrometer is often employed to allow for simultaneous analysis of distinct signals. This is especially important when performing spatially resolved diffuse reflectance spectroscopy. In this article, an algorithm is presented that allows for the automated processing of 2-dimensional images acquired from an imaging spectrometer...
December 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28032280/fluorescent-nanocomposite-of-embedded-ceria-nanoparticles-in-electrospun-chitosan-nanofibers
#19
Nader Shehata, Effat Samir, Soha Gaballah, Aya Hamed, Marwa Saad, Mohammed Salah
This paper introduces a detailed optical characterization for a novel fluorescent biodegradable nanocomposite of electro-spun chitosan nanofibers with in-situ embedded cerium oxide (ceria) nanoparticles as the nanocomposite optical fluorescent material. Under near ultra-violet excitation, this synthesized nanocomposite emits a visible green wavelength at nearly 520nmwith different intensities according to the concentration of the embedded fluorescent material; i.e. ceria nanoparticles. This emission is due to the synthesized ceria nanoparticles optical tri-valiant cerium ions ce(3+), associated with formed oxygen vacancies with a direct allowed bandgap around 3...
December 28, 2016: Journal of Fluorescence
https://www.readbyqxmd.com/read/28029779/hydrogel-droplet-microfluidics-for-high-throughput-single-molecule-cell-analysis
#20
Zhi Zhu, Chaoyong James Yang
Heterogeneity among individual molecules and cells has posed significant challenges to traditional bulk assays, due to the assumption of average behavior, which would lose important biological information in heterogeneity and result in a misleading interpretation. Single molecule/cell analysis has become an important and emerging field in biological and biomedical research for insights into heterogeneity between large populations at high resolution. Compared with the ensemble bulk method, single molecule/cell analysis explores the information on time trajectories, conformational states, and interactions of individual molecules/cells, all key factors in the study of chemical and biological reaction pathways...
December 28, 2016: Accounts of Chemical Research
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