Multifunctional nanocomposites based on graphite-phase carbon nitride quantum dots-silver nanospheres for combined photothermal-photodynamic anti-tumor therapy

In recent years, photonic therapy (photothermal and photodynamic therapy) has gradually aroused great interest among researchers in related fields as new methods of tumor treatment. However, a single phototherapy modality alone such as photodynamic therapy or photothermal therapy, has shown limited therapeutic efficacy in tumor treatment. To overcome the limitations of monotherapy, a combined photothermal-photodynamic treatment strategy based on graphite-phase carbon nitride quantum dots (g-CNQDs) and silver nanospheres (AgNSs) has been employed in this work. Specifically, g-CNQDs@AgNSs nanocomposite was prepared by loading g-CNQDs onto AgNSs surface through metal amino coordination and in-situ reduction method. g-CNQDs serves as the photosensitizer whereas AgNSs acts as a photothermal agent. This nanocomposite not only has good biocompatibility but also has good photothermal properties and generates excellent reactive oxygen species under near-infrared light irradiation. In vitro or cellular experimental results show that combination therapy provides a significant improvement in photothermal and photodynamic efficacy as compared to that of monotherapy. In essence, this work offers a secure and powerful strategy for efficient combination therapy of tumors with promising applications.