Fluoropolymer Nanosheet as a Wrapping Mount for High-Quality Tissue Imaging.

In the field of biological microscopy technology, it is still a practical challenge to obtain high-quality tissue images, due to the tissue desiccation that occurs during observations without an effective sample mounting. Inspired by the use of plastic food wrap, this study proposes the use of polymer thin films (also known as nanosheets) to fix the tissue samples. Water-repellent nanosheets composed of the amorphous fluoropolymer CYTOP are prepared with adjustable thicknesses and their hydrophobicity, transparency, and adhesion strength are evaluated. They show excellent water-retention effect and work well for sample fixation. By wrapping cleared mouse brain slices with a 133 nm thick CYTOP nanosheet, this study achieves high spatial resolution neuron images while scanning over a large area for a long period of time. No visible artifacts arising from sample shrinkage can be detected. This study also expects that nanosheet wrapping could be effective over a longer time span by combination with conventional agarose embedding.