Nucleolus-Targeting\nCarbon Dot Nanocomplexes for Combined\nPhotodynamic/Photothermal Therapy

The low cure rate and high mortality associated with\ncancer pose\nsignificant threats to human health. Photodynamic and photothermal\ntherapies have emerged as promising treatment strategies for various\ntypes of cancers. In this study, we successfully synthesized a novel\ntype of carbon dot (CD) using 1,2,4-aminobenzene and ethylenediamine\nas precursors. Surprisingly, these CDs exhibited outstanding nucleolus-targeting\ncapabilities coupled with a remarkable photothermal effect. Through\nthe integration of these nucleolus-targeting CDs with indocyanine\ngreen (ICG) and folic acid (FA), we created CDs-ICG-FA nanocomplexes\nsuitable for combined photodynamic and photothermal therapy. In vitro\nexperiments demonstrated that CDs-ICG-FA maintained a robust photothermal\nability, achieving a conversion efficiency of up to 34.3%. Furthermore,\nCDs-ICG-FA generated abundant reactive oxygen species, effectively\ninducing cancer cell death and demonstrating its potential for photodynamic\ntherapy. In MCF-7 cancer cells, CDs-ICG-FA exhibited a pronounced\nsynergistic photothermal/photodynamic anticancer effect. Subsequent\nin vivo experiments in mice revealed that CDs-ICG-FA could selectively\naccumulate at tumor sites, significantly inhibiting tumor growth upon\nexposure to an 808 nm laser. These findings suggest that the developed\nnucleolus-targeting CDs-ICG-FA hold promising potential for cancer\ntargeting and the application of combined photothermal/photodynamic\ntherapy.