Ruthenium nitrosyl grafted carbon dots as a fluorescence-trackable nanoplatform for visible light-controlled nitric oxide release and targeted intracellular delivery

Nitric oxide (NO) plays a key role in various physiological and pathological processes. It is of great significance in developing a platform that enables exogenous delivery of NO spatiotemporally to a targeted site for realizing NO-mediated therapy. We report herein a stable, multifunctional NO-delivery nanoplatform that is capable of target directing, fluorescence tracking, and light-controlled NO delivery. A ruthenium nitrosyl [Ru(TPY^COOH)(o-phenylenediamine)(NO)](PF₆)₃ and a target-directing molecule of folic acid (FA) were covalently grafted onto the surface of a carrier of carbon dots (CDs), forming a {Ru-NO@FA@CDs} nanoplatform. This nanoplatform is fluorescence self-trackable in a cellular environment and can recognize specific cancer cells via FA-folate receptor binding; it was selectively taken up by cancer cells to enter the cytosol, in which localized NO was produced on demand by adept control of visible light illumination. This offered the potential for treating diseases derived from NO deficiency as well as NO-mediated cancer therapy.