Department of Biomedical Engineering, National University of Singapore, Singapore.
J Biophotonics. 2019 Jul;12(7):e201800459. doi: 10.1002/jbio.201800459. Epub 2019 Apr 1.
Fluorescence imaging in the second near-infrared optical window (NIR-II, 900-1700 nm) has become a technique of choice for noninvasive in vivo imaging in recent years. Greater penetration depths with high spatial resolution and low background can be achieved with this NIR-II window, owing to low autofluorescence within this optical range and reduced scattering of long wavelength photons. Here, we present a novel design of confocal laser scanning microscope tailored for imaging in the NIR-II window. We showcase the outstanding penetration depth of our confocal setup with a series of imaging experiments. HeLa cells labeled with PbS quantum dots with a peak emission wavelength of 1276 nm can be visualized through a 3.5-mm-thick layer of scattering medium, which is a 0.8% Lipofundin solution. A commercially available organic dye IR-1061 (emission peak at 1132 nm), in its native form, is used for the first time, as a NIR-II fluorescence label in cellular imaging. Our confocal setup is capable of capturing optically sectioned images of IR-1061 labeled chondrocytes in fixed animal cartilage at a depth up to 800 μm, with a superb spatial resolution of around 2 μm.
近年来，荧光在近红外二区（NIR-II，900-1700nm）中的成像已经成为一种非侵入式活体成像的首选技术。该近红外二区具有较低的自发荧光和长波长光子的低散射特性，因此可以实现更高的穿透深度、更高的空间分辨率和更低的背景。在这里，我们提出了一种专门针对 NIR-II 窗口成像的共焦激光扫描显微镜的新设计。我们通过一系列成像实验展示了我们的共焦设置的出色穿透深度。峰值发射波长为 1276nm 的 PbS 量子点标记的 HeLa 细胞可以通过 3.5mm 厚的散射介质层（0.8%的 Lipofundin 溶液）可视化。我们首次将商业上可获得的有机染料 IR-1061（发射峰在 1132nm）以其天然形式用作细胞成像的 NIR-II 荧光标记。我们的共焦装置能够以出色的空间分辨率（约 2μm）捕获固定动物软骨中标记有 IR-1061 的软骨细胞的光学切片图像，深度可达 800μm。
