Indocyanine green-loaded N-doped carbon quantum dot nanoparticles for effective photodynamic therapy and cell imaging of melanoma cancer: In vitro, ex vivo and in vivo study.

N-doped carbon quantum dot (CQD) nanoparticle was prepared as a novel nanocarrier with excellent solubility, stability, and high quantum yield to overcome Indocyanine Green (ICG) obstacle in photodynamic therapy (PDT) with simultaneous cell imaging property. Cell culture study and In vivo assessments on the C57BL/6 mice containing melanoma cancer cells was performed. Results showed that CQD size after ICG loading slightly enhanced from 24.55 nm to 42.67 nm. Detection of reactive oxygen species (ROS) test demonstrated that CQD improved ICG photo-stability and ROS generation capacity upon laser irradiation. Cell culture study illustrated that ICG@CQD could decrease the survival rate of melanoma cancer cells of B16F10 cell line from 48% for pure ICG drug to 28% for ICG@CQD. Captured images by confocal microscopy approved more cellular uptake of ICG@CQD and more qualified cell imaging ability of the nanocarrier. In vivo assessments on the C57BL/6 mice containing melanoma cancer cells displayed the obvious inhibitory effect of the tumor growth for ICG@CQD in comparison to free ICG. In vivo fluorescence images confirmed that ICG@CQD accumulates remarkably more than free ICG in the tumor region. In conclusion, ICG@CQD is proposed as an innovative nanocarrier with great potential for PDT and diagnosis.