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[IEEE 2018 IEEE International Ultrasonics Symposium (IUS) - Kobe, Japan (2018.10.22-2018.10.25)] 2018 IEEE International Ultrasonics Symposium (IUS) - Simulation of Photoacoustic Imaging of Red Blood Cell Aggregation Using a Numerical Model of Pulsatile Blood Flow
摘要： Photocatalytic imaging of blood flow using a pulsed laser diode of semiconductor blood flow aggregation and oxygenation saturation (sO2) estimation. During blood flow aggregation, the oxygen saturation of the blood flow is affected by the interaction between red blood cell (RBC) aggregation and the oxygen saturation (sO2) [1-7]. The mechanism of the aggregation is not yet fully understood. To date, two models, namely the bridging and depletion models, are proposed for explaining the kinetics of RBC aggregation [20-21]. Using the proposed models, new efforts have been published to investigate the kinetics of RBC aggregation [22-24]. In this paper, a simple particle motion model in two-dimensional (2D) space was introduced to understand the photothermal imaging of blood flow aggregation from the flow model. The flow model consisted of 125 elements spaced at 10 μm center-to-center, yielding a lateral length of 22.0 mm. The incident laser fluence was less than 10 mJ/cm2, below the safety limit by the American National Standards Institute (ANSI) for these wavelengths. The photothermal power (PTP) was computed from the flow model at each time step, and the simulated PTP was compared to the measured PTP in vivo. From the comparison, the kinetics of RBC aggregation was studied.
关键词： blood flow,aggregation,photocatalytic imaging,photothermal power,kinetics,red blood cell,oxygenation saturation
更新于2025-09-23 15:23:52
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Erythrocyte membrane nano-capsules: biomimetic delivery and controlled release of photothermala??photochemical coupling agents for cancer cell therapy
摘要： Photothermal therapy (PTT), which involves an increase in temperature triggered only by light signals at tumor sites to remove cancer cells, has been considered an attractive strategy in cancer therapy. Nevertheless, the in vivo applications of photosensitizer-based PTT are limited due to the poor biocompatibility of photothermal agents. Employing red blood cell (RBC) membranes to encapsulate photothermal agents can solve this issue, but the extra surface coating will suppress heat dissipation, which is unfavorable for the subsequent treatment. Herein, biomimetic nano-capsules have been fabricated for light signal-activated cancer therapy by encapsulating photocatalyst titanium dioxide colloid and photothermal agent gold nanorods (Au NRs) in erythrocyte membrane vesicles. The fabricated Au/TiO2@RBC nano-capsules can achieve the controlled release of Au NRs upon the photocatalytic degradation of their surface cell membrane coatings, and generate therapeutic signals after the released Au NRs are irradiated by an NIR laser. Meanwhile, the reactive oxygen species (ROS) produced by photocatalysis are helpful for killing tumor cells photodynamically. Thus, the biomimetic nano-capsules prepared herein will contribute to the research and development in cancer cell therapy.
关键词： cancer therapy,titanium dioxide,red blood cell membranes,biomimetic nano-capsules,gold nanorods,Photothermal therapy
更新于2025-09-19 17:13:59
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Optofluidic laser speckle image decorrelation analysis for the assessment of red blood cell storage
摘要： Red blood cells (RBCs) undergo irreversible biochemical and morphological changes during storage, contributing to the hemorheological changes of stored RBCs, which causes deterioration of microvascular perfusion in vivo. In this study, a home-built optofluidic system for laser speckle imaging of flowing stored RBCs through a transparent microfluidic channel was employed. The speckle decorrelation time (SDT) provides a quantitative measure of RBC changes, including aggregation in the microchannel. The SDT and relative light transmission intensity of the stored RBCs were monitored for 42 days. In addition, correlations between the decorrelation time, RBC flow speed through the channel, and relative light transmission intensity were obtained. The SDT of stored RBCs increased as the storage duration increased. The SDTs of the RBCs stored for 21 days did not significantly change. However, for the RBCs stored for over 35 days, the SDT increased significantly from 1.26 ± 0.27 ms to 6.12 ± 1.98 ms. In addition, we measured the relative light transmission intensity and RBC flow speed. As the RBC storage time increased, the relative light transmission intensity increased, whereas the RBC flow speed decreased in the microchannel. The optofluidic laser speckle image decorrelation time provides a quantitative measure of assessing the RBC condition during storage. Laser speckle image decorrelation analysis may serve as a convenient assay to monitor the property changes of stored RBCs.
关键词： laser speckle,image decorrelation,microfluidic channel,Optofluidic,RBC aggregation,speckle decorrelation time,red blood cell storage
更新于2025-09-19 17:13:59
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Fast confocal fluorescence imaging in freely behaving mice
摘要： Fluorescence imaging in the brain of freely behaving mice is challenging due to severe miniaturization constraints. In particular, the ability to image a large field of view at high temporal resolution and with efficient out-of-focus background rejection still raises technical difficulties. Here, we present a novel fiberscope system that provides fast (up to 200 Hz) background-free fluorescence imaging in freely behaving mice over a field of view of diameter 230 μm. The fiberscope is composed of a custom-made multipoint-scanning confocal microscope coupled to the animal with an image guide and a micro-objective. By simultaneously registering a multipoint-scanning confocal image and a conventional widefield image, we subtracted the residual out-of-focus background and provided a background-free confocal image. Illumination and detection pinholes were created using a digital micromirror device, providing high adaptability to the sample structure and imaging conditions. Using this novel imaging tool, we demonstrated fast fluorescence imaging of microvasculature up to 120 μm deep in the mouse cortex, with an out-of-focus background reduced by two orders of magnitude compared with widefield microscopy. Taking advantage of the high acquisition rate (200 Hz), we measured red blood cell velocity in the cortical microvasculature and showed an increase in awake, unrestrained mice compared with anaesthetized animals.
关键词： red blood cell velocity,multipoint-scanning confocal microscope,digital micromirror device,fiberscope system,microvasculature imaging,fluorescence imaging,freely behaving mice
更新于2025-09-09 09:28:46