Solvatochromic Two-Photon Fluorescent Probe Enables In Situ Lipid Droplet Multidynamics Tracking for Nonalcoholic Fatty Liver and Inflammation Diagnoses

Intracellular lipid storage and regulation occur in lipid droplets, which are of great significance to the physiological activities of cells. Herein, a lipid droplet-specific fluorescence probe (lip-YB) with a high quantum yield (QY lip‑YB = 73.28%), excellent photostability, and quickly polarity sensitivity was constructed successfully. Interestingly, lip-YB exhibited remarkable two-photon (TP) characteristics, which first realized real-time monitoring of the lipid droplet multidynamics process, diagnosing nonalcoholic fatty liver disease (NAFLD) and inflammation in living mice via TP fluorescence imaging. It is found that the as-prepared lip-YB provides a new avenue to design lipid droplet-specific imaging probes, clarifies its roles and mechanisms in cell metabolism, and can timely intervene in lipid droplet-related diseases during various physiological and pathological processes.