pH-Induced color changeable AIE-featured polymeric micelles for self-indicating anticancer drug delivery

Multifunctional polymeric micelles, which possess capabilities for tracking, bioimaging, stimuli-responsive drug release and tumor targeting, are essential in facilitating the effective delivery of anticancer drugs. Hence, a novel copolymer (CD-CS-Bio-TPAA, CCBT) was synthesized with biotin and hydroxypropyl-β-cyclodextrin conjugated chitosan as the hydrophilic segment and aggregation-induced emission (AIE) featured tetraphenylethene derivative (TPAA) as the hydrophobic segment. Interestingly, under acidic conditions, CCBT exhibited color-tunable AIE behavior as a result of the cleavage of benzoic imine bonds in TPAA molecules, transitioning from red to yellow. Furthermore, CCBT could also self-assemble into polymeric micelles and be used as drug carriers to encapsulate paclitaxel (PTX) (PTX/CCBT PMs) for self-indicating cancer therapy. In vitro release experiments demonstrated that PTX/CCBT PMs could release drugs specifically under acidic conditions. Fluorescence imaging experiments demonstrated that CCBT PMs exhibited excellent cell imaging capabilities and could be tracked due to their unique color-changing behavior. Moreover, PTX/CCBT PMs exhibited notable cytotoxic effects on MCF-7 cells and showed selective internalization by MCF-7 cells through biotin receptor-mediated active targeting. In vivo antitumor experiments confirmed that PTX/CCBT PMs possessed remarkable tumor-inhibiting effects and low systemic toxicity. This work suggested that PTX/CCBT PMs provided new ideas for self-indicating breast cancer treatment.