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- 实验方案
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Dual-Modal Imaging-Guided Precise Tracking of Bioorthogonally Labeled Mesenchymal Stem Cells in Mouse Brain Stroke
摘要： Non-invasive and precise stem cell tracking after transplantation in living subject is very important to monitor both stem cell destinations and their in vivo fate, which was closely related to their therapeutic efficacy. Herein, we developed bicyclo[6.1.0]nonyne (BCN)-conjugated glycol chitosan nanoparticles (BCN-NPs) as a delivery system of dual-modal stem cell imaging probes. Near-infrared fluorescent (NIRF) dye, Cy5.5, was chemically conjugated to the BCN-NPs and then oleic acid-coated superparamagnetic iron oxide nanoparticles (OA-Fe3O4 NPs) were encapsulated into BCN-NPs, in resulting Cy5.5-labeled and OA-Fe3O4 NP-encapsulated BCN-NPs (BCN-dual-NPs). For bioorthogonal labeling of human adipose-derived mesenchymal stem cells (hMSCs), firstly, hMSCs were treated with tetra-acetylated N-azidoacetyl-D-mannosamine (Ac4ManNAz) for generating azide (-N3) groups onto their surface via metabolic glycoengineering. Second, azide groups on the cell surface were successfully chemically labeled with BCN-dual-NPs via bioorthogonal click chemistry in vitro. This bioorthogonal labeling of hMSCs could greatly increase the cell labeling efficiency, safety, and imaging sensitivity, compared to only nanoparticle-derived labeling technology. The dual-modal imaging-guided precise tracking of bioorthogonally labeled hMSCs was tested in the photothrombotic stroke mouse model via intraparenchymal injection. Finally, BCN-dual-NPs-labeled hMSCs could be effectively tracked of their migration from implanted site to brain stroke lesion using NIRF/T2-weighted magnetic resonance (MR) dual-modal imaging for 14 days. Our observation would provide a potential application of bioorthogonally labeled stem cell imaging in regenerative medicine by providing safety and high labeling efficiency in vitro and in vivo.
关键词： metabolic engineering,dual-modal imaging,bioorthogonal click chemistry,stem cell tracking,imaging probe,brain stroke
更新于2025-09-16 10:30:52
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Instantaneous brain stroke classification and localization from real scattering data
摘要： This work presents a 2-step Learning-by-Examples approach for the real-time classification of hemorrhagic/ischemic brain strokes and their successive localization from microwave scattering data collected around the human head. An experimental assessment against laboratory-controlled data is performed to assess the potentialities of the proposed approach towards a reliable monitoring and instantaneous diagnosis clinic protocol.
关键词： inverse scattering,experimental data,support vector machine (SVM),brain stroke microwave imaging,learning-by-examples (LBE)
更新于2025-09-10 09:29:36
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Three-Dimensional Holographic Electromagnetic Imaging for Accessing Brain Stroke
摘要： The authors recently developed a two-dimensional (2D) holographic electromagnetic induction imaging (HEI) for biomedical imaging applications. However, this method was unable to detect small inclusions accurately. For example, only one of two inclusions can be detected in the reconstructed image if the two inclusions were located at the same XY plane but in different Z-directions. This paper provides a theoretical framework of three-dimensional (3D) HEI to accurately and effectively detect inclusions embedded in a biological object. A numerical system, including a realistic head phantom, a 16-element excitation sensor array, a 16-element receiving sensor array, and image processing model has been developed to evaluate the effectiveness of the proposed method for detecting small stroke. The achieved 3D HEI images have been compared with 2D HEI images. Simulation results show that the 3D HEI method can accurately and effectively identify small inclusions even when two inclusions are located at the same XY plane but in different Z-directions. This preliminary study shows that the proposed method has the potential to develop a useful imaging tool for the diagnosis of neurological diseases and injuries in the future.
关键词： brain stroke,sensor array,dielectric properties,electromagnetic induction imaging,magnetic induction tomography
更新于2025-09-09 09:28:46