Carbonized Polymer Dots with Aggregation-Induced Effect for Type I Photodynamic Therapy

Carbonized polymer dots (CPDs) have attracted great interest as a nanomaterial in biomedical applications, especially in imaging and photodynamic therapy (PDT). However, CPDs with an aggregation-induced effect for type I PDT has been rarely reported. In this work, N,N′-dimethylurea and citric acid were used as precursors to prepare CPDs (YCPDs) with aggregation-induced effect in one pot by the solvothermal method. The YCPDs have a yellow emission of 550 nm and a high quantum yield of 68%, which lays a solid foundation for cell imaging. In addition, YCPDs can produce ^•O₂^– under white light irradiation and obtain ^•OH through electron transfer or hydrogen atom abstraction. In vitro results show that YCPDs possess great cytocompatibility but exert severe cytotoxicity to HeLa cells with only 2% of cell viability when exposed to ultralow-power-intensity (2.5 mW/cm²) light irradiation. Therefore, YCPDs, as a promising type I PDT nanomaterial, have a great potential for cancer therapy.