Carbon dots inspired by structure-inherent targeting for nucleic acid imaging and localized photodynamic therapy

Targeting capability is one of the most important properties of both imaging and therapeutic agents. The discovery of “structure-inherent targeting” (SIT) phenomena has benefitted the tailored design of fluorescent probes and photodynamic photosensitizers. Herein, SIT was combined with the inheritance of epigenetic characteristics from parent carbon sources to synthesize nucleic acid-targeted carbon dots (CDs) from quinoline derivatives, namely, 1-CDs, Cl-CDs, and I-CDs via a bottom-up strategy. These CDs exhibited RNA-selective fluorescence imaging, as confirmed using cell digestion, SYTO® RNASelect™ costaining, and nucleic acid titration. Furthermore, owing to iodine doping, I-CDs exhibited excellent PDT performance for killing cancer cells in vitro. Importantly, I-CDs could actively target and become enriched at tumor sites using folic acid-functionalized liposomes as tumor-homing vehicles, thus effectively inhibiting tumor growth in vivo. By screening the SIT carbon source, photodynamic CDs can provide a new platform for next-generation nucleic acid-targeting photodynamic therapy.