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Biomedical optics

Catia Contado, Roberto Argazzi, Vincenzo Amendola
Many advanced industrial and biomedical applications that use silver nanoparticles (AgNPs), require that particles are not only nano-sized, but also well dispersed, not aggregated and not agglomerated. This study presents two methods able to give rapidly sizes of monodispersed AgNPs suspensions in the dimensional range of 20-100nm. The first method, based on the application of Mie's theory, determines the particle sizes from the values of the surface plasmon resonance wavelength (SPRMAX), read from the optical absorption spectra, recorded between 190nm and 800nm...
October 13, 2016: Journal of Chromatography. A
Gavin D Merrifield, James Mullin, Lindsay Gallagher, Carl Tucker, Maurits A Jansen, Martin Denvir, William M Holmes
Increasing scientific interest in the zebrafish as a model organism across a range of biomedical and biological research areas raises the need for the development of in vivo imaging tools appropriate to this subject. Development of the embryonic and early stage forms of the subject can currently be assessed using optical based techniques due to the transparent nature of the species at these early stages. However this is not an option during the juvenile and adult stages when the subjects become opaque. Magnetic Resonance Imaging (MRI) techniques would allow for the longitudinal and non-invasive assessment of development and health in these later life stages...
October 14, 2016: Magnetic Resonance Imaging
Elke Duchardt-Ferner, Michael Juen, Christoph Kreutz, Jens Wöhnert
RNA aptamers are used in a wide range of biotechnological or biomedical applications. In many cases the high resolution structures of these aptamers in their ligand-complexes have revealed fundamental aspects of RNA folding and RNA small molecule interactions. Fluorescent RNA-ligand complexes in particular find applications as optical sensors or as endogenous fluorescent tags for RNA tracking in vivo. Structures of RNA aptamers and aptamer ligand complexes constitute the starting point for rational function directed optimization approaches...
October 11, 2016: Biomolecular NMR Assignments
Amit Kumar, Sungi Kim, Jwa-Min Nam
The localized surface plasmon resonance of metal nanopar-ticles is the collective oscillation of electrons on particle surface, and is a particle composition, morphology and cou-pling-dependent property. Plasmonic engineering deals with highly precise formation of the targeted nanostructures with targeted plasmonic properties (e.g., electromagnetic field distribution and enhancement) via controlled synthetic, assembling and atomic/molecular tuning strategies. These plasmonically engineered nanostructures (PENs) have a variety of unique and beneficial physical, chemical and bio-logical properties including optical signal enhancement, catalytic property and local temperature-tuning photother-mal property...
October 10, 2016: Journal of the American Chemical Society
Qingliang Zhao, Cuixia Dai, Shanhui Fan, Jing Lv, Liming Nie
Salicylic acid (SA) has been frequently used as a facial chemical peeling agent (FCPA) in various cosmetics for facial rejuvenation and dermatological treatments in the clinic. However, there is a tradeoff between therapeutic effectiveness and possible adverse effects caused by this agent for cosmetologists. To optimize the cosmetic efficacy with minimal concentration, we proposed a chemical permeation enhancer (CPE) azone to synergistically work with SA on human skin in vivo. The optical properties of human skin after being treated with SA alone and SA combined with azone (SA@azone) were successively investigated by diffuse reflectance spectroscopy (DRS) and optical coherence tomography (OCT)...
October 10, 2016: Scientific Reports
Zi Long, Meiying Liu, Qing Wan, Liucheng Mao, Hongye Huang, Guangjian Zeng, Yiqun Wan, Fengjie Deng, Xiaoyong Zhang, Yen Wei
The development of effective strategies for fabrication of fluorescent organic nanoparticles (FONs) with an aggregation-induced emission (AIE) feature has an important impact on the biomedical applications of these AIE-active FONs. In the current work, an ultrafast strategy for fabricating AIE-active FONs is developed through a "one-pot" microwave-assisted, catalysts-free, and solvent-free Kabachnik-Fields (KF) reaction for the first time. It is demonstrated that such organophosphorous-containing AIE-active block polymers can be synthesized within 2 min under air atmosphere through the microwave-assisted KF reaction...
September 26, 2016: Macromolecular Rapid Communications
Pearse A Keane, Carlota M Grossi, Paul J Foster, Qi Yang, Charles A Reisman, Kinpui Chan, Tunde Peto, Dhanes Thomas, Praveen J Patel
PURPOSE: To describe an approach to the use of optical coherence tomography (OCT) imaging in large, population-based studies, including methods for OCT image acquisition, storage, and the remote, rapid, automated analysis of retinal thickness. METHODS: In UK Biobank, OCT images were acquired between 2009 and 2010 using a commercially available "spectral domain" OCT device (3D OCT-1000, Topcon). Images were obtained using a raster scan protocol, 6 mm x 6 mm in area, and consisting of 128 B-scans...
2016: PloS One
Ritika Joshi, Oinam Romesh Meitei, Manojkumar Jadhao, Himank Kumar, Sujit Kumar Ghosh
The legacy of phosphorescence from expensive organometallic compounds has inspired researchers to develop efficient metal-free organic phosphors. Although organic phosphors offer a cheaper alternative, the long-lived triplets of organic phosphors that are primarily consumed by vibrational dissipation need to be adequately suppressed, and this provides an opportunity to design new organic entities, at par with the organometallic compounds, based on conformational control and incorporation of useful functional groups to alter their emissive properties, especially phosphorescence...
October 12, 2016: Physical Chemistry Chemical Physics: PCCP
Lauren M Sparks, Leanne M Redman, Kevin E Conley, Mary-Ellen Harper, Andrew Hodges, Alexey Eroshkin, Sheila R Costford, Meghan E Gabriel, Fanchao Yi, Cherie Shook, Heather H Cornnell, Eric Ravussin, Steven R Smith
CONTEXT: Reduced mitochondrial coupling (P/O) is associated with sedentariness and insulin resistance. Interpreting the physiological relevance of P/O measured in vitro is challenging. OBJECTIVE: To evaluate muscle mitochondrial function and associated transcriptional profiles in non-obese healthy individuals distinguished by their in vivo P/O. DESIGN: Individuals from an ancillary study of CALERIE Phase 2 were assessed at baseline. SETTING: The study was performed at Pennington Biomedical Research Center in Baton Rouge, LA, USA...
October 6, 2016: Journal of Clinical Endocrinology and Metabolism
Hua He, Zhencai Wang, Tiantian Cheng, Xu Liu, Xiaojuan Wang, Junying Wang, Hao Ren, Yawei Sun, Yanzhuo Song, Jiang Yang, Yongqing Xia, Shengjie Wang, Xiao-Dong Zhang, Fang Huang
Fluorescence imaging requires bio-selective, sensitive, nontoxic molecular probes to detect precise location of lesions for fundamental research and clinical applications. Typical inorganic semiconductor nanomaterials with large sizes (> 10 nm) can offer high-quality fluorescence imaging due to their fascinating optical properties, but are limited to low selectivity as well as slow clearance pathway. We here report an N- and O-rich carbogenic small molecular complex (SMC, MW < 1000 Da) that exhibit high quantum yield (up to 80%), nucleic acid-binding enhanced excitation-dependent fluorescence (EDF) and a near infrared (NIR) emission peaked at 850 nm with an ultra-large Stokes shift (~ 500 nm)...
October 5, 2016: ACS Applied Materials & Interfaces
Feng Lu, Jongwon Lee, Aiting Jiang, Seungyong Jung, Mikhail A Belkin
Polarimetric imaging is widely used in applications from material analysis to biomedical diagnostics, vision and astronomy. The degree of circular polarization, or light ellipticity, is associated with the S3 Stokes parameter which is defined as the difference in the intensities of the left- and right-circularly polarized components of light. Traditional way of determining this parameter relies on using several external optical elements, such as polarizers and wave plates, along with conventional photodetectors, and performing at least two measurements to distinguish left- and right-circularly polarized light components...
October 5, 2016: Nature Communications
Ádám Krolopp, Attila Csákányi, Dóra Haluszka, Dániel Csáti, Lajos Vass, Attila Kolonics, Norbert Wikonkál, Róbert Szipőcs
A novel, Yb-fiber laser based, handheld 2PEF/SHG microscope imaging system is introduced. It is suitable for in vivo imaging of murine skin at an average power level as low as 5 mW at 200 kHz sampling rate. Amplified and compressed laser pulses having a spectral bandwidth of 8 to 12 nm at around 1030 nm excite the biological samples at a ~1.89 MHz repetition rate, which explains how the high quality two-photon excitation fluorescence (2PEF) and second harmonic generation (SHG) images are obtained at the average power level of a laser pointer...
September 1, 2016: Biomedical Optics Express
A V Raut, H M Yadav, A Gnanamani, S Pushpavanam, S H Pawar
In the present investigation, novel strategy for the preparation of hybrid nanocomposite containing organic polymer (Chitosan) and inorganic (TiO2:Cu) nanoparticles (NPs) has been developed and demonstrated its biomedical application. The sol-gel and ultra-sonication method assisted for the preparation of uniformly distributed Chitosan-TiO2:Cu (CS-CT) nanocomposite. The structural properties of prepared CS-CT nanocomposite were studied by XRD and FTIR techniques. The XPS was used to estimate elemental composition of the nanocomposite...
September 22, 2016: Colloids and Surfaces. B, Biointerfaces
Zdenka Bujňáková, Matej Baláž, Erika Dutková, Peter Baláž, Martin Kello, Gabriela Mojžišová, Ján Mojžiš, Mária Vilková, Ján Imrich, Miroslav Psotka
The wet mechanochemical procedure for the capping of the CdS and CdS/ZnS quantum dot nanocrystals is reported. l-cysteine and polyvinylpyrrolidone (PVP) were used as capping agents. When using l-cysteine, the dissolution of cadmium(II) was almost none for CdS/ZnS nanocrystals. Moreover, prepared CdS- and CdS/ZnS-cysteine nanosuspensions exhibited unimodal particle size distributions with very good stability, which was further supported by the zeta potential measurements. The Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy showed the successful embedment of cysteine into the structure of the nanocrystals...
September 15, 2016: Journal of Colloid and Interface Science
Maurizio Burla, Xu Wang, Ming Li, Lukas Chrostowski, José Azaña
Photonic-based instantaneous frequency measurement (IFM) of unknown microwave signals offers improved flexibility and frequency range as compared with electronic solutions. However, no photonic platform has ever demonstrated the key capability to perform dynamic IFM, as required in real-world applications. In addition, all demonstrations to date employ bulky components or need high optical power for operation. Here we demonstrate an integrated photonic IFM system that can identify frequency-varying signals in a dynamic manner, without any need for fast measurement instrumentation...
2016: Nature Communications
Feiyue Zhang, Xiaowen Liang, Wenzhu Zhang, Yong-Lei Wang, Haolu Wang, Yousuf H Mohammed, Bo Song, Run Zhang, Jingli Yuan
Although hypochlorous acid (HOCl) has long been associated with a number of inflammatory diseases in mammalian bodies, the functions of HOCl in specific organs at abnormal conditions, such as liver injury, remain unclear due to its high reactivity and the lack of effective methods for its detection. Herein, a unique Ir(III) complex-based chemosensor, Ir-Fc, was developed for highly sensitive and selective detection of HOCl. Ir-Fc was designed by incorporating a ferrocene (Fc) quencher to a Ir(III) complex through a HOCl-responsive linker...
September 20, 2016: Biosensors & Bioelectronics
Ryan S Edginton, Sara Mattana, Silvia Caponi, Daniele Fioretto, Ellen Green, C Peter Winlove, Francesca Palombo
Brillouin spectroscopy is an emerging technique in the biomedical field. It probes the mechanical properties of a sample through the interaction of visible light with thermally induced acoustic waves or phonons propagating at a speed of a few km/sec. Information on the elasticity and structure of the material is obtained in a nondestructive contactless manner, hence opening the way to in vivo applications and potential diagnosis of pathology. This work describes the application of Brillouin spectroscopy to the study of biomechanics in elastin and trypsin-digested type I collagen fibers of the extracellular matrix...
2016: Journal of Visualized Experiments: JoVE
Lorenzo Sansalone, Sicheng Tang, Yang Zhang, Ek Raj Thapaliya, Françisco M Raymo, Jaume Garcia-Amorós
Photochromic or photocaged ligands can be anchored to the outer shell of semiconductor quantum dots in order to control the photophysical properties of these inorganic nanocrystals with optical stimulations. One of the two interconvertible states of the photoresponsive ligands can be designed to accept either an electron or energy from the excited quantum dots and quench their luminescence. Under these conditions, the reversible transformations of photochromic ligands or the irreversible cleavage of photocaged counterparts translates into the possibility to switch luminescence with external control...
October 2016: Top Curr Chem (J)
Guy Satat, Barmak Heshmat, Dan Raviv, Ramesh Raskar
Imaging through thick highly scattering media (sample thickness ≫ mean free path) can realize broad applications in biomedical and industrial imaging as well as remote sensing. Here we propose a computational "All Photons Imaging" (API) framework that utilizes time-resolved measurement for imaging through thick volumetric scattering by using both early arrived (non-scattered) and diffused photons. As opposed to other methods which aim to lock on specific photons (coherent, ballistic, acoustically modulated, etc...
September 29, 2016: Scientific Reports
Núria Gavara
Atomic Force microscopy (AFM) is becoming a prevalent tool in cell biology and biomedical studies, especially those focusing on the mechanical properties of cells and tissues. The newest generation of bio-AFMs combine ease of use and seamless integration with live-cell epifluorescence or more advanced optical microscopies. As a unique feature with respect to other bionanotools, AFM provides nanometer-resolution maps for cell topography, stiffness, viscoelasticity, and adhesion, often overlaid with matching optical images of the probed cells...
September 27, 2016: Microscopy Research and Technique
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