Investigation On High Resolution In Vivo Fluorescence Bioimaging In The Second Near-infrared Region

Fluorescence bioimaging,with the advantages of non-invasive,non-ironized,high spatial resolution and highly informative,is an indispensable tool for biomedical research and clinical diagnosis.Recently,second near-infrared region(NIR-?,900?1700 nm)fluorescence imaging has been a hot research area,due to its low scattering and the ability to reveal details of vasculature and organs.However,it still faces the challenge of lacking sufficient NIR-? probes and imaging systems,as well as the relevant experiments in non-human primates models.Here,we aim at solving these difficulties by focusing on the following issues:First,we completed NIR-? fluorescence microscopic imaging of cortical vasculature in non-human primates with high resolution.We developed two NIR-?fluorescence microscopic systems for brain vasculature imaging in large animals.Both were designed with flexibility to image various cortical locations on the head.We utilized a clinically-approved indocyanine green as probe and implemented in vivo experiments in macaque monkeys.The wide-field microscope adopted "area-excitation,area-detection" approach,which offered high temporal resolution(25 frames/second),and realized the measurement of blood flow velocity and cardiac impulse period.The confocal microscope,based on "point-excitation,point-detection",enabled a high spatial resolution of?8 ?m and a vivid 3D reconstructed images from 0?470 ?mSecond,we for the first time realized NIR-?b(1500?1700 nm)in vivo fluorescence imaging based on aggregation-induced emission(AIE)materials.We utilized AIE nanoprobe with high quantum yield to conduct a serious of in vivo imaging experiments in mice.We performed the whole-body angiography with low background,bowel imaging with a clear differentiation of gastrointestinal,and through-skull brain vasculature imaging with a resolution of?10 ?m.These experiments showed an enhanced imaging quality over NIR-? region.This work comprises an important tool for investigating brain function and mechanics of diseases relevant to brain vasculatures,and provides a step towards in vivo NIR-?b fluorescence imaging with organic probes.