Facile fabrication of cupric ion-carbon quantum dots as tumor-specific nanotheranostics for cuprous ion-mediated chemodynamic therapy and real-time fluorescence imaging

Abstract

Carbon quantum dots (CDs) have attracted intense interest in biomedical imaging. However, their very small diameter and non-characteristic fluorescence limit the practical application. Herein, Cu(II)-complexed CDs (Cu(II)-CDs NPs) have been designed via facile complexing CDs with Cu(II) ions, for the tumor intracellular glutathione-activated cuprous ion-mediated chemodynamic therapy and real-time fluorescence imaging. They were quite stable in both neutral and weakly acidic solutions even with lower glutathione (GSH)-level and dilution, emitting very weak fluorescence, while as in the simulated intracellular microenvironment, slight or strong fluorescence was emitted in the normal or tumor cells, respectively. Especially, they could release CDs and Cu(I) ions due to GSH-triggered disintegration. Such features make them promising nanotheranostics in tumor treatment, and the tumor-specific cuprous ion-mediated chemodynamic therapy and real-time fluorescence imaging were revealed in the in vitro cellular tests.