Carbon Dots with Intrinsic Theranostic Properties for Bioimaging, Red-Light-Triggered Photodynamic/Photothermal Simultaneous Therapy In Vitro and In Vivo.

Cancer nanotheranostics combining therapeutic and imaging functions within a single nanoplatform are extremely important for nanomedicine. In this study, carbon dots (C-dots) with intrinsic theranostic properties are prepared by using polythiophene benzoic acid as carbon source. The obtained C-dots absorb light in the range of 400-700 nm and emit bright fluorescence in the red region (peaking from 640 to 680 nm at different excitations). More importantly, the obtained C-dots exhibit dual photodynamic and photothermal effects under 635 nm laser irradiation with a singlet oxygen ((1)O2) generating efficiency of 27% and high photothermal conversion efficiency of 36.2%. These unique properties enable C-dots to act as a red-light-triggered theranostic agent for imaging-guided photodynamic-photothermal simultaneous therapy in vitro and in vivo within the therapeutic window (600-1000 nm).