Traceable pH/near-infrared dual-responsive chitosan quantum dots/polypyrrole nanocarrier for efficient and...

Chitosan quantum dots (CQDs) have garnered significant attention in the field of non-viral gene delivery owing to their excellent biocompatibility, fluorescence characteristics, and gene loading capacity. However, the single CQDs system faces challenges such as limited DNA loading capacity, premature release in physiological environments, and a lack of stimulus responsiveness. This work innovatively combines CQDs with polypyrrole (PPy) to construct a multifunctional gene delivery system with fluorescence tracing and pH/near-infrared dual-responsive controlled release capabilities. This system integrates the high gene loading and fluorescence tracing abilities of CQDs with the photothermal conversion characteristics of PPy, enabling visualization and precise controlled release during the gene delivery process. As expected, the DNA release rate of CQDs/PPy/DNA exceeded 80 % under pH = 5.0 and near-infrared (NIR) irradiation, with transfection efficiencies of 54.96 % and 36.48 % in 293 T and HeLa cells, respectively, and significantly reduced cytotoxicity. After 4 min of NIR irradiation, the transfection efficiency significantly increased. This work breaks through the bottleneck of traditional non-viral vectors with limited functionality and provides an important foundation for the development of an intelligent "diagnosis and treatment integration" gene delivery platform.