Upconverting Carbon Nanodots from EDTA as Near-Infrared Activated Phototheranostic Agents.

This work describes the synthesis of nitrogen-doped carbon nanodots (CNDs) synthesized from ethylene diamine tetra acetic acid (EDTA) as a precursor and their application as luminescent agents with a dual-mode theranostic role as near-infrared (NIR) triggered imaging and photodynamic therapy agents. Interestingly, these fluorescent CNDs are more rapidly and selectively internalized in tumor cells and exhibit no cytotoxicity until remotely activated with a NIR illumination source. These CNDs are excellent candidates for photo-theranostic purposes, i.e.: simultaneous imaging and therapy can be carried out on cancer cells using their luminescent properties and the in situ generation of reactive oxidative species (ROS) upon excitation in the NIR range. In the presence of CNDs NIR remote activation induces the in vitro killing of U251 MG cells. Through the use of flow imaging cytometry we have been able to successfully map and quantify the different type of cell deaths induced by the presence of intracellular superoxide anions (●O2-) and hydrogen peroxide (H2O2) ROS species generated in situ upon NIR irradiation.