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  • 1.

    【2hr】Differential detachment of intact and viable cells of different sizes using laser-induced microbubbles

    包量

    机译 使用激光诱导的微泡区分大小不同的完整细胞和活细胞
    摘要：Single cell isolation is a prerequisite for the analysis of rare or small cell subtypes. Here, we selectively detach single cells in a heterogeneous population comprised of different morphological subtypes whose sizes vary in body and extension. Such a cellular environment is first accommodated for by a photomechanical method in which pulsed laser irradiation produces microbubbles from a polymer substrate, thus pushing out and detaching cultured cells in an intact, viable, and spatially tailored way. While this has previously only bene used at a very low cell density with lack of quantitative characterization, we determine optimal detachment conditions for different cell sizes in terms of an optical fluence and the number of laser pulses. Importantly, our approach is employed to isolate cancer cells with inherent size variation and elucidate cellular heterogeneity in drug sensitivity: i.e., higher resistance for larger cell size. For cells detached by laser-induced microbubbles, morphology, proliferation, and viability are compared with those of conventional trypsin-treated cells detached without any spatial selectivity. These results support the suitability of our photomechanical method for biochemical screen and secondary analysis of cells with unusual responses.
  • 2.

    【2hr】Effective demethylation of melanoma cells using terahertz radiation

    包量

    机译 使用太赫兹辐射对黑素瘤细胞进行有效的去甲基化
    摘要：Terahertz (THz) demethylation is a photomedical technique applied to dissociate methyl-DNA bonds and reduce global DNA methylation using resonant THz radiation. We evaluated the performance of THz demethylation and investigated the DNA damage caused by THz irradiation. The demethylation rate in M-293T DNA increased linearly with the irradiation power up to 48%. The degree of demethylation increased with exposure to THz radiation, saturating after 10 min. Although THz demethylation occurred globally, most of the demethylation occurred within the partial genes in the CpG islands. Subsequently, we performed THz demethylation of melanoma cells. The degree of methylation in the melanoma cell pellets decreased by approximately 10–15%, inducing ∼5–8 abasic sites per 105 bp; this was considerably less than the damaged DNA irradiated by the high-power infrared laser beam used for generating THz pulses. These results provide initial data for THz demethylation and demonstrate the applicability of this technique in advanced cancer cell research. THz demethylation has the potential to develop into a therapeutic procedure for cancer, similar to that involving chemical demethylating agents.
  • 3.

    【2hr】Waveform analysis of human retinal and choroidal blood flow with laser Doppler holography

    包量

    机译 激光多普勒全息术分析人视网膜和脉络膜血流的波形
    摘要：Laser Doppler holography was introduced as a full-field imaging technique to measure blood flow in the retina and choroid with an as yet unrivaled temporal resolution. We here investigate separating the different contributions to the power Doppler signal in order to isolate the flow waveforms of vessels in the posterior pole of the human eye. Distinct flow behaviors are found in retinal arteries and veins with seemingly interrelated waveforms. We demonstrate a full field mapping of the local resistivity index, and the possibility to perform unambiguous identification of retinal arteries and veins on the basis of their systolodiastolic variations. Finally we investigate the arterial flow waveforms in the retina and choroid and find synchronous and similar waveforms, although with a lower pulsatility in choroidal arteries. This work demonstrates the potential held by laser Doppler holography to study ocular hemodynamics in healthy and diseased eyes.
  • 4.

    【2hr】Ptychographic imaging of NaD1 induced yeast cell death

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    机译 NaD1诱导酵母细胞死亡的声像图成像
    摘要：Characterising and understanding the mechanisms involved in cell death are especially important to combating threats to human health, particularly for the study of antimicrobial peptides and their effectiveness against pathogenic fungi. However, imaging these processes often relies on the use of synthetic molecules which bind to specific cellular targets to produce contrast. Here we study yeast cell death, induced by the anti-fungal peptide, NaD1. By treating yeast as a model organism we aim to understand anti-fungal cell death processes without relying on sample modification. Using a quantitative phase imaging technique, ptychography, we were able to produce label free images of yeast cells during death and use them to investigate the mode of action of NaD1. Using this technique we were able to identify a significant phase shift which provided a clear signature of yeast cell death. Additionally, ptychography identifies cell death much earlier than a comparative fluorescence study, providing new insights into the cellular changes that occur during cell death. The results indicate ptychography has great potential as a means of providing additional information about cellular processes which otherwise may be masked by indirect labelling approaches.
  • 5.

    【2hr】Quantitative assessment of changes in cellular morphology at photodynamic treatment in vitro by means of digital holographic microscopy

    包量

    机译 借助数字全息显微镜对光动力治疗中细胞形态变化的定量评估
    摘要：Temporal dependence of changes in the morphological characteristics of cells of two cultured lines of cancer origin, HeLa and A549, induced by photodynamic treatment with Radachlorin photosensitizer, have been monitored using digital holographic microscopy during first two hours after short-term irradiation. The observed post-treatment early dynamics of the phase shift in the transmitted wavefront indicated several distinct scenarios of cell behavior depending upon the irradiation dose. In particular the phase shift increased at low doses, which can be associated with apoptosis, while at high doses it decreased, which can be associated with necrosis. As shown, the two cell types responded differently to similar irradiation doses. Although the sequence of death scenarios with the increase of the irradiation dose was the same, each scenario was realized at substantially different doses. These findings suggest that the average phase shift of the transmitted wavefront can be used for quantitative non-invasive cell death characterization. The conclusions made were cofirmed by commonly used test assays using confocal fluorescent microscopy.
  • 6.

    【2hr】Electric-field-assisted signal amplification for label-free liquid-crystal-based detection of biomolecules

    包量

    机译 电场辅助信号放大，用于基于无标记液晶的生物分子检测
    摘要：The fundamental principle of liquid-crystal (LC)-based biosensing is the sensitive response of LC orientation to external stimuli. Biomolecules such as proteins or DNAs immobilized on the glass substrate of a LC cell are detected through disrupting the LC alignment and, in turn, altering the birefringence, resulting in changes in the optical texture that can be readily observed under a polarizing optical microscope. With an additional weak electric field across a sandwiched LC cell, we demonstrate in this study a novel label-free biodetection technique with amplified signal and improved detection limit. By applying the binarization analysis as the quantitative approach, the increase in the light leakage area in the optical texture of LCs with increasing amount of biomolecules can be quantitated with a bright-area-ratio (BAR)-versus-concentration curve. The reported biosensing technique exploits both the optical and electrical properties of LCs and is potentially applicable to other LC-based rapid screening and bioassays.
  • 7.

    【2hr】Early diagnosis of gastric cancer based on deep learning combined with the spectral-spatial classification method

    包量

    机译 基于深度学习结合光谱空间分类方法的胃癌早期诊断
    摘要：The development of an objective and rapid method that can be used for the early diagnosis of gastric cancer has important clinical application value. In this study, the fluorescence hyperspectral imaging technique was used to acquire fluorescence spectral images. Deep learning combined with spectral-spatial classification methods based on 120 fresh tissues samples that had a confirmed diagnosis by histopathological examinations was used to automatically identify and extract the “spectral + spatial” features to construct an early diagnosis model of gastric cancer. The model results showed that the overall accuracy for the nonprecancerous lesion, precancerous lesion, and gastric cancer groups was 96.5% with specificities of 96.0%, 97.3%, and 96.7% and sensitivities of 97.0%, 96.3%, and 96.6%, respectively. Therefore, the proposed method can increase the diagnostic accuracy and is expected to be a new method for the early diagnosis of gastric cancer.
  • 8.

    【2hr】Visual method for evaluating liver function: targeted in vivo fluorescence imaging of the asialoglycoprotein receptor

    包量

    机译 评估肝功能的视觉方法：靶向去唾液酸糖蛋白受体的体内荧光成像
    摘要：The visual evaluation of liver function (LF) has always been a hot topic in research on liver diseases. In vivo fluorescence imaging (IVFI) of the Cy5.5-galactosylated polylysine (Cy5.5-GP) probe targeting asialoglycoprotein receptor (ASGPR), for evaluating LF in chronic alcoholic liver injury (cALI) mice was investigated in this study. The decrease of fluorescence signals in the livers showed a biological relationship with the liver ASGPR expression, histology, and serum marker levels of LF in cALI mice. The targeted IVFI of ASGPR as a novel method can intuitively and noninvasively display the characteristics of liver’s ASGPR level to provide a reference for evaluating LF.
  • 9.

    【2hr】Polar organization of collagen in human cardiac tissue revealed with polarimetric second-harmonic generation microscopy

    包量

    机译 偏振二次谐波显微镜显示人心脏组织中胶原蛋白的极性组织
    摘要：Polarimetric second-harmonic generation (P-SHG) microscopy is used to characterize the composition and polarity of collagen fibers in various regions of human cardiac tissue. The boundary between the cardiac conduction system and myocardium is shown to possess a distinct composition of collagen compared to other regions in the heart. Moreover, collagen fibers in this region are macroscopically organized in a unipolar arrangement, which may consequently aid in effective propagation of the electrical signal through the cardiac conduction system.
  • 10.

    【2hr】Method to improve the depth sensitivity of diffuse reflectance measurements to absorption changes in optically turbid medium

    包量

    机译 提高漫反射率测量对光学混浊介质中吸收变化的深度敏感性的方法
    摘要：We have studied the spatial distributions of the sensitivity of time-resolved near-infrared diffuse reflectance measurement. Sensitivity factors representing a change of parameters of a measured optical signal induced by absorption perturbation in a certain voxel of the medium were simulated using the diffusion equation solution. The parameters were statistical moments of measured distributions of time of flight of photons (DTOFs) i.e., the total number of photons, mean time of flight and variance. The distributions of the sensitivity of statistical moments of DTOFs to a change in absorption were generated for various source-detector separations and various optical properties of the medium. Furthermore, differential sensitivity distributions for two different source-detector separations were calculated. A measurement geometry, in which two detection spots, separated by 5 mm, in combination with two sources was proposed. For this setup differences between the signals obtained for both detectors were calculated independently for both sources and afterward summed up for both source positions. Obtained differences in moments of DTOFs assessed at two source-detector separations and summed up for different positioning of the sources allowed to shape up the sensitivity profiles. Calculated sensitivity profiles show that positive sensitivities of the mean time of flight of photons and variance of the DTOF can be obtained. These positive sensitivity areas are located just between both detection spots and cover the compartment located deeply in the medium. The sensitivity in superficial compartments of the medium is negative and much smaller in amplitude. The proposed technique can be used for improved discrimination of optical signals related to the intracerebral change in absorption which remains a serious obstacle in the application of the NIRS technique in the assessment of brain oxygenation or perfusion.
  • 11.

    【2hr】Deep learning based topology guaranteed surface and MME segmentation of multiple sclerosis subjects from retinal OCT

    包量

    机译 基于深度学习的拓扑结构可确保视网膜OCT的多发性硬化受试者的表面和MME分割
    摘要：Optical coherence tomography (OCT) is a noninvasive imaging modality that can be used to obtain depth images of the retina. Patients with multiple sclerosis (MS) have thinning retinal nerve fiber and ganglion cell layers, and approximately 5% of MS patients will develop microcystic macular edema (MME) within the retina. Segmentation of both the retinal layers and MME can provide important information to help monitor MS progression. Graph-based segmentation with machine learning preprocessing is the leading method for retinal layer segmentation, providing accurate surface delineations with the correct topological ordering. However, graph methods are time-consuming and they do not optimally incorporate joint MME segmentation. This paper presents a deep network that extracts continuous, smooth, and topology-guaranteed surfaces and MMEs. The network learns shape priors automatically during training rather than being hard-coded as in graph methods. In this new approach, retinal surfaces and MMEs are segmented together with two cascaded deep networks in a single feed forward propagation. The proposed framework obtains retinal surfaces (separating the layers) with sub-pixel surface accuracy comparable to the best existing graph methods and MMEs with better accuracy than the state-of-the-art method. The full segmentation operation takes only ten seconds for a 3D volume.
  • 12.

    【2hr】Aberration-free multi-plane imaging of neural activity from the mammalian brain using a fast-switching liquid crystal spatial light modulator

    包量

    机译 使用快速切换液晶空间光调制器的哺乳动物大脑神经活动的无像差多平面成像
    摘要：We report a novel two-photon fluorescence microscope based on a fast-switching liquid crystal spatial light modulator and a pair of galvo-resonant scanners for large-scale recording of neural activity from the mammalian brain. The spatial light modulator is used to achieve fast switching between different imaging planes in multi-plane imaging and correct for intrinsic optical aberrations associated with this imaging scheme. The utilized imaging technique is capable of monitoring the neural activity from large populations of neurons with known coordinates spread across different layers of the neocortex in awake and behaving mice, regardless of the fluorescent labeling strategy. During each imaging session, all visual stimulus driven somatic activity could be recorded in the same behavior state. We observed heterogeneous response to different types of visual stimuli from ∼ 3,300 excitatory neurons reaching from layer II/III to V of the striate cortex.
  • 13.

    【2hr】Classification of diffuse light emission profiles for distinguishing skin layer penetration of a needle-free jet injection

    包量

    机译 漫射光发射轮廓的分类，以区分无针喷射注射的皮肤层穿透力
    摘要：In this work, a system is developed for tracking the skin layer to which a needle-free jet injection of fluid has penetrated by incorporating a laser beam into the jet, and measuring the diffuse light emitted from skin tissue. Monitoring the injection in this way offers the ability to improve the reliability of drug delivery with this transdermal delivery method. A laser beam, axially aligned with a jet of fluid, created a distribution of diffuse light around the injection site that varied as the injection progressed. High-speed videography was used to capture the diffuse light emission from laser-coupled jet injections into samples of porcine skin, fat, and muscle. The injection produced a distribution of diffuse light around the injection site that varied as the injection descended. A classifier, trained to distinguish whether the light source was located in the fat or muscle from surface intensity profile measurements, correctly identified the injected layer in 97.2% of the cases when cross-examined against estimates using the light distribution emitted from the side of the sample.
  • 14.

    【2hr】Concurrent fluorescence and volumetric optoacoustic tomography of nanoagent perfusion and bio-distribution in solid tumors

    包量

    机译 实体瘤中纳米剂灌注和生物分布的同时荧光和体积光声层析成像
    摘要：Intravenously administered liposomes and other nano-sized particles are known to passively accumulate in solid tumors via the enhanced permeability and retention (EPR) effect, which is extensively explored toward the improvement of diagnosis and drug delivery in oncology. Agent extravasation into tumors is often hampered by the mononuclear phagocytic and renal systems, which sequester and/or eliminate most of the nanoparticles from the body. Dynamic imaging of the tumor microcirculation and bolus perfusion can thus facilitate optimization of the nanoparticle delivery. When it comes to non-invasive visualization of rapid biological dynamics in whole tumors, the currently available pre-clinical imaging modalities are commonly limited by shallow penetration, lack of suitable contrast or otherwise insufficient spatial or temporal resolution. Herein, we demonstrate the unique capabilities of a combined epi-fluorescence and optoacoustic tomography (FLOT) system for characterizing contrast agent dynamics in orthotopic breast tumors in mice. A liposomal indocyanine green (Lipo-ICG) preparation was administered intravenously with the time-lapse data continuously acquired during and after the injection procedure. In addition to the highly sensitive detection of the fluorescence agent by the epi-fluorescence modality, the volumetric multi-spectral optoacoustic tomography readings further enabled resolving deep-seated vascular structures with high spatial resolution and hence provided accurate readings of the dynamic bio-distribution of nanoparticles in the entire tumor in 3D. The synergetic combination of the two modalities can become a powerful tool in cancer research and potentially aid the diagnosis, staging and treatment guidance of certain types of cancer in the clinical setting.
  • 15.

    【2hr】Transdermal fluorescence detection of a dual fluorophore system for noninvasive point-of-care gastrointestinal permeability measurement

    包量

    机译 双荧光团系统的透皮荧光检测，用于非侵入性即时护理胃肠道通透性测量
    摘要：The intestinal mucosal barrier prevents macromolecules and pathogens from entering the circulatory stream. Tight junctions in this barrier are compromised in inflammatory bowel diseases, environmental enteropathy, and enteric dysfunction. Dual sugar absorption tests are a standard method for measuring gastrointestinal integrity, however, these are not clinically amenable. Herein, we report on a dual fluorophore system and fluorescence detection instrumentation for which gastrointestinal permeability is determined in a rat small bowel disease model from the longitudinal measured transdermal fluorescence of each fluorophore. This fluorophore technology enables a specimen-free, noninvasive, point-of-care gastrointestinal permeability measurement which should be translatable to human clinical studies.
  • 16.

    【2hr】High-resolution VSDI retinotopic mapping via a DLP-based projection system

    包量

    机译 通过基于DLP的投影系统进行高分辨率VSDI视网膜定位
    摘要：High-resolution recording of visual cortex activity is an important tool for vision research. Using a customized digital mirror device (DMD) - based system equipped with retinal imaging, we projected visual stimuli directly on the rat retina and recorded cortical responses by voltage-sensitive dye imaging. We obtained robust cortical responses and generated high-resolution retinotopic maps at an unprecedented retinal resolution of 4.6 degrees in the field of view, while further distinguishing between normal and pathological retinal areas. This system is a useful tool for studying the cortical response to localized retinal stimulation and may shed light on various cortical plasticity processes.
  • 17.

    【2hr】Live imaging of contracting muscles with wide-field second harmonic generation microscopy using a high power laser

    包量

    机译 使用大功率激光通过大范围二次谐波产生显微镜对收缩的肌肉进行实时成像
    摘要：Wide-field second harmonic generation (SHG) microscopy was developed using a high-power (> 4 W) and high-repetition-rate (MHz range) laser oscillator to achieve fast SHG imaging over a large area (400 µm × 400 µm). The microscope was used for high spatial resolution imaging of contracting muscles in live Drosophila melanogaster larvae. Anisotropic and isotropic bands of striated muscle were distinguished, allowing accurate determination of sarcomere length and SHG intensity from individual sarcomeres. Therefore, wide-field SHG microscopy has applications in basic contractility research and studying arrhythmias, muscular dystrophies and pharmaceutical effects on the muscle contraction dynamics of sarcomeres.
  • 18.

    【2hr】Label-free and specific detection of soluble programmed death ligand-1 using a localized surface plasmon resonance biosensor based on excessively tilted fiber gratings

    包量

    机译 使用基于过度倾斜的光纤光栅的局部表面等离振子共振生物传感器，对无标记的可溶性程序性死亡配体-1进行特异性检测
    摘要：Programmed death ligand-1 (PD-L1) plays an important role in tumor evasion from the host immune system. The level of soluble PD-L1 (sPD-L1) in serum is closely related to tumor aggressiveness and outcomes. This study aimed to propose a localized surface Plasmon resonance (LSPR) biosensor based on excessively tilted fiber grating (ExTFG) coated with large-sized (∼160 nm) gold nanoshells for label-free and specific detection of sPD-L1. The experimental results showed that the limit of detection (LOD) of the immunosensor for sPD-L1 in buffer solutions was ∼1 pg/mL due to the enhanced LSPR effect resulting from the interaction between sPD-L1 molecules and anti-sPD-L1 monoclonal antibodies. The detection of sPD-L1 in complex serum media, such as fetal bovine serum, confirmed that the label-free immunosensor was extremely specific to sPD-L1 and could identify it at a concentration as low as 5 pg/mL. Therefore, it can be potentially applied in clinic for the fast and early diagnosis of cancer.
  • 19.

    【2hr】Handheld motion stabilized laser speckle imaging

    包量

    机译 手持式运动稳定激光散斑成像
    摘要：Laser speckle imaging (LSI) is a wide-field, noninvasive optical technique that allows researchers and clinicians to quantify blood flow in a variety of applications. However, traditional LSI devices are cart or tripod based mounted systems that are bulky and potentially difficult to maneuver in a clinical setting. We previously showed that the use of a handheld LSI device with the use of a fiducial marker (FM) to account for motion artifact is a viable alternative to mounted systems. Here we incorporated a handheld gimbal stabilizer (HGS) to produce a motion stabilized LSI (msLSI) device to further improve the quality of data acquired in handheld configurations. We evaluated the msLSI device in vitro using flow phantom experiments and in vivo using a dorsal window chamber model. For in vitro experiments, we quantified the speckle contrast of the FM (KFM) using the mounted data set and tested 80% and 85% of KFM as thresholds for useable images (KFM,Mounted,80% and KFM,Mounted,85%). Handheld data sets using the msLSI device (stabilized handheld) and handheld data sets without the HGS (handheld) were collected. Using KFM,Mounted,80% and KFM,Mounted,85% as the threshold, the number of images above the threshold for stabilized handheld (38 ± 7 and 10 ± 2) was significantly greater (p = 0.031) than for handheld operation (16 ± 2 and 4 ± 1). We quantified a region of interest within the flow region (KFLOW), which led to a percent difference of 8.5% ± 2.9% and 7.8% ± 3.1% between stabilized handheld and handheld configurations at each threshold. For in vivo experiments, we quantified the speckle contrast of the window chamber (KWC) using the mounted data set and tested 80% of KWC (KWC,Mounted,80%). Stabilized handheld operation provided 53 ± 24 images above KWC,Mounted,80%, while handheld operation provided only 23 ± 13 images. We quantified the speckle flow index (SFI) of the vessels and the background to calculate a signal-to-background ratio (SBR) of the window chamber. Stabilized handheld operation provided a greater SBR (2.32 ± 0.29) compared to handheld operation (1.83 ± 0.21). Both the number of images above threshold and SBR were statistically significantly greater in the stabilized handheld data sets (p = 0.0312). These results display the improved usability of handheld data acquired with an msLSI device.
  • 20.

    【2hr】Recent progress in optical probing and manipulation of tissue: introduction

    包量

    机译 光学探测和组织操纵的最新进展：介绍
    摘要：This feature issue of Biomedical Optics Express represents a cross-section of the most recent work in tissue optics, including exciting developments in tissue optical clearing, deep tissue imaging, optical elastography, nanophotonics in tissue, and therapeutic applications of light, amongst others. A collection of 33 papers provides a comprehensive overview of current research in tissue optics, much of it inspired and informed by the pioneering work of Prof. Valery Tuchin. The issue contains three invited manuscripts and several mini-reviews that we hope will benefit researchers in this exciting area.
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