NIR-responsive carbon dots as an oxidative-stress amplifier and hyperthermia-induced superior photothermal in-vitro anticancer activity.

A facile wet chemistry-based strategy was developed to synthesize orange emissive Carbon dots (O-CDs) based on dehydration-induced ring-fusion of the precursor (1,3-dihydroxynaphthalene) in a dehydrating sulfuric acid medium. The O-CDs revealed significant Near-infrared (808 nm) light harvesting potential with outstanding photothermal conversion efficiency (∼58%) and hence exhibited excellent NIR-light stimulated photothermal anticancer performance. Furthermore, these fluorescent O-CD nanoprobes displayed excitation-dependent polychromatic emissions in the range of 540–640 nm, with the dual emission maxima at 540 and 580 nm, corresponding to yellow and orange emission at the excitation of 490 nm. Various mitochondrial, as well as cytoplasmic apoptosis-related proteins and genes were upregulated during photothermal treatment, which suggests that hyperthermia and oxidative stress have a major impact on cell death. The anticancer activity of O-CDs is likely due to the elevated reactive oxygen species (ROS) amplification in cooperation with the hyperthermia effect. This study offers a potential alternative to bio-nanomedicine for cancer treatment by carbon-based photothermal therapy. [Display omitted] • Polyphenolic CDs with extended π-conjugation and orange emission were prepared. • Hydrophilic O-CDs showed good NIR-harvesting potential with excellent PCE∼58%. • Apoptosis-related proteins and genes were upregulated due to the photothermal effect • NIR-induced oxidative-stress in cooperation with hyperthermia, kills cancer cells. [ABSTRACT FROM AUTHOR]