Shortwave-Infrared Line-Scan Confocal Microscope for Deep Tissue Imaging in Intact Organs

The recent developments of fluorophores having photoemission beyond 1000nm provide the opportunity to develop novel fluorescent microscopes sensitive to those wavelengths. The imaging at wavelengths beyond the visible spectrum allows to achieve imaging depths of hundreds of microns in intact tissue, making this attractive for volumetric imaging applications. Here, a novel shortwave-infrared line-scan confocal microscope is presented that is capable of deep imaging of biological specimens, as demonstrated by visualization of labelled glomeruli in a fixed uncleared kidney at depths of 300μm to 400μm. This development improves the acquisition speed of deep tissue fluorescence imaging.