Degradable pH-responsive polymer prodrug micelles with aggregation-induced emission for cellular imaging and cancer therapy

Abstract Polymeric micelles with simultaneous bioimaging, drug delivery monitoring, and effective delivery of therapeutic agents to target sites have attracted increasing attention in cancer therapy. In this study, a new biodegradable, pH-responsive, aggregation-induced emission (AIE)-active polycarbonate brush-like polymer was developed by combining ring-opening polymerization with click reaction. The anticancer drug, doxorubicin (DOX), was covalently conjugated to the polymer backbone via acid-sensitive Schiff base linkage, resulting in the pH-sensitive controlled release of DOX. The prodrug polymer self-assembled into nanomicelles in an aqueous solution, as confirmed using dynamic light scattering and transmission electron microscopy. Fluorescence imaging results demonstrated that prodrug micelles could be traced owing to the AIE features of micelles. In vitro drug release studies showed that DOX release was faster in acidic conditions (pH 5.0), whereas only a minimal amount of DOX was released in a physiological environment (pH 7.4). In summary, these smart prodrug micelles could be promising candidates for simultaneous intracellular imaging and cancer therapy.