pH-Responsive Charge-Convertible N-Succinyl Chitosan-Quercetin Coordination Polymer Nanoparticles for Effective NIR Photothermal Cancer Therapy

In recent years, a combination of photothermal therapy (PTT) with chemotherapy has emerged as a new promising strategy to achieve synergistic cancer therapeutic efficacy. Coordination polymer nanocomposites (CPNs) are a new generation of photothermal agents (PTAs) for cancer therapy owing to their high photothermal transduction efficiency, excellent biocompatibility as well as biodegradability and bioactivity. In this study, a robust and scalable synthesis of pH-sensitive charge convertible NSC-Fe-Que coordination polymer nanoparticles (CPNs) based on the coordination reaction between Fe3+, anti-cancer prodrug quercetin (Que), and pH-sensitive zwitterionic biopolymer N-succinyl chitosan (NSC) is reported. The as-prepared CPNs exhibit slightly negative zeta potential at neutral pH while positive zeta potential at pH 6.5, which ensures long blood circulation and high accumulation in the tumor region. NSC-Fe-Que CPNs exhibited strong absorption in NIR (500-850 nm) region and displayed a good anticancer effect against A549 cells attributing to the chemo-photothermal synergistic effect. This study demonstrated that the NSC-Fe-Que CPNs hold great promise as an effective thermo-chemotherapy agent for combination therapy against cancer.