Dual-Responsive Doxorubicin-Conjugated Polymeric Micelles with Aggregation-Induced Emission Active Bioimaging and Charge Conversion for Cancer Therapy

In recent years, intelligent polymeric micelles with multifunctions are in urgent demand for cancer diagnosis and therapy. Herein, pH and redox dual-responsive prodrug micelles with aggregation-induced emission (AIE) active cellular imaging and charge conversion have been prepared for combined chemotherapy and bioimaging based on a novel doxorubicin-conjugated amphiphilic PMPC-PAEMA-P (TPE-co-HD)-ss-P (TPE-co-HD)-PAEMA-PMPC copolymer. The doxorubicin is conjugated via a pH cleavable imine linkage and can be packed in the hydrophobic core along with the glutathione (GSH)-sensitive disulfide bond. The DOX-conjugated inner core is sealed with a pH-responsive PAEMA as the "gate", which would rapidly open in the acidic condition, following the drug release and charge conversion-mediated acceleration of endocytosis. After an efficient internalization, the disulfide bond can be cleaved by the high concentration of GSH causing the further accelerated drug release. Meanwhile, intracellular drug delivery can be traced due to the AIE behavior of micelles. Moreover, great tumor inhibition in vitro and in vivo has been demonstrated for these DOX-conjugated micelles. This smart prodrug micelle system would be a desirable drug carrier for cancer therapy and bioimaging.