A pH-responsive nanoplatform with aggregation-induced emission features for lipid droplet imaging in atherosclerosis

Hydrophobic lipid droplets (LDs)-specific fluorescent probes have shown great potential in bioimaging. However, their in vivo bioapplications are also limited by their strong hydrophobic nature. To address this issue, we prepared a novel tetraphenylethylene (TPE)-based fluorescent probe, namely, MeOTTI, and a pH-responsive polymeric micelle to establish a nanodiagnostic system for the imaging of LDs in atherosclerosis. MeOTTI demonstrated good LDs-specific imaging capability with good anti-photobleaching ability but poor water solubility. MeOTTI-encapsulated nanoparticles (MeOTTI-PMEA NPs) have shown improved water solubility and biocompatibility of MeOTTI. MeOTTI-PMEA NPs exhibited great stability at pH 7.4, while they showed good acid-responsive ability with accelerated MeOTTI release. Importantly, MeOTTI-PMEA NPs could efficiently light up the LDs in cells and in mice atherosclerosis plaques. The construction of LDs-specific probe-loaded nanodiagnostic system is expected to create enthusiasm for the development of new tools for bioimaging.