Fluorescent Silver-AIE Visualization of Neurons and Fibres in the Cleared Brain

Herein, we report a novel fluorogenic visualization method for mouse brain tissues by making use of a Ag+-specific aggregation-induced emission (AIE) strategy after silver impregnation. This novel fluorogenic silver-AIE method surpasses the chromogenic detection used by many conventional silver staining protocols, which have historically made revolutionary contributions to neuroanatomy. This fluorescent silver-based stain allows for analysis of images acquired using wide-field, confocal, SIMs, or light-sheet fluorescence microscopy. We validated the sensitivity, specificity, and versatility of the silver-AIE stain as compared to conventional silver stains and other neuron-specific ones. The silver-AIE stain is demonstrated to be highly compatible with immunofluorescence co-staining in paraffin sections and can be applied to hydrogel-based cleared tissue by the passive CLARITY method for image analysis of large tissue slices of 300 μm thick in this study. From this fluorogenic strategy, it is possible for vast types of classic silver staining methods to be modified and re-vitalized.