Intravital confocal fluorescence lifetime imaging microscopy in the second near-infrared window

摘要

We present confocal fluorescence lifetime imaging microscopy in the second near-infrared (NIR-II) window to assess the morphological and biochemical information of live samples. A home-built superconducting single-photon detector (SSPD) was used to facilitate the NIR-II fluorescence lifetime measurement. The SSPD has many advantages, including high sensitivity to NIR-II signals (detection efficiency >50%), fast temporal response (similar to 109 ps), low timing jitter (similar to 50 ps), and low dark count rate (<100 cps). We demonstrate the feasibility of the developed microscopy system by comparing fluorescence lifetimes of a range of fluorophores with emission in the NIR-II window and by performing multicolor three-dimensional fluorescence lifetime imaging of a mouse ear in vivo. The biochemical properties of the cells and tissues probed by the fluorescence lifetimes of the fluorophores provide complementary information for biomedical studies, significantly benefiting diverse applications in life science.

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