Dual-Responsive Micelles with Aggregation-Induced Emission Feature and Two-Photon Aborsption for Accurate Drug Delivery and Bioimaging.

Intelligent polymeric micelles provide great potential for accurate cancer theranostics. Herein, gemcitabine (GEM)-conjugated redox-responsive prodrug micelles based on a pH-responsive charge-conventional PMPC- b-P (DEMA- co-SS-GEM- co-TPMA) copolymer and a two-photon absorbing aggregation-induced emission (AIE) fluorescence probe have been developed for lysosome-targeted drug release and bioimaging. The multifunctional copolymer has been synthesized via RAFT polymerization, and GEM is conjugated to the copolymer via GSH-cleavable disulfide bonds. These GEM-conjugated micelles exhibit great pH responsiveness at pH 5.0, while being stable at pH 6.0. GSH-triggered drug release can be observed with the GSH concentration increased from 0 to 10 mM. Moreover, the high-quality AIE-active two-photon imaging is confirmed by cell and deep-tissue imaging. More importantly, the distribution of these nanocarriers can be traced because of the AIE feature of the micelles. Along with good in vitro and in vivo tumor-suppression ability and significantly reduced side effects, this smart two-photon AIE micelle would be a potential candidate for cancer diagnosis and therapy.