Multifunctional carbon dots with near-infrared absorption and emission for targeted delivery of anticancer drugs, tumor tissue imaging and chemo/photothermal synergistic therapy

Cancer therapy faces considerable challenges related to improving treatment efficiency and overcoming damage to healthy cells. To address these concerns, a strategy for tumor microenvironment-induced cancer imaging/drug release and synergistic chemo-photothermal therapy (chemo/PTT) is proposed in this study. Carbon dots with near-infrared (NIR) absorption and emission, referred to as RCDs, were first prepared and covalently coupled with a Pt( iv ) prodrug to form a complex, referred to as RCD-Pt( iv ). The surface of the prepared complex was then coated with the polyethylene glycol-chitosan-2,3-dimethylmaleic anhydride polymer (PEG-CS-DA) to obtain a tumor-targeted multifunctional nanoprobe (RCD-Pt( iv )/PEG-CS-DA). When the nanoprobe RCD-Pt( iv )/PEG-CS-DA entered the tumor cells, the acidic environment of the tumor cells allowed rapid PEG-CS-DA hydrolysis and RCD-Pt( iv ) release. High levels of glutathione (GSH) in cancer cells reduced Pt( iv ) to Pt( ii ) and released the RCDs, resulting in cancer tissue imaging and targeted Pt( ii ) release. Meanwhile, Pt( ii ) collected in the tumor tissues could realize targeted chemotherapy, and the RCDs in the tumor tissues absorbed light energy under NIR light irradiation to produce a large amount of heat to quickly eliminate cancer cells. Thus, cancer tissue imaging/targeted drug release and synergistic chemo/PTT were achieved simultaneously. A multifunctional nanoprobe for tumor microenvironment- induced cancer imaging and chemo/PTT synergistic targeted therapy was constructed. Tumor microenvironment-specific stimuli responses enable targeted drug accumulation and cancer imaging.