Organotin(IV)-Decorated Graphene Quantum Dots as Dual Platform for Molecular Imaging and Treatment of Triple Negative Breast Cancer.

The pharmacological activity of organotin(IV) complexes in cancer therapy is well recognized but their large applicability is hampered by their poor water solubility. Hence, carbon dots, in particular nitrogen-doped graphene quantum dots (NGQDs), may be a promising alternative for the efficient delivery of organotin(IV) compounds as they have a substantial aqueous solubility, a good chemical stability, and non-toxicity as well as a bright photoluminescence that make them ideal for theranostic applications against cancer. Two different multifunctional nanosystems have been synthesized and fully characterized based on two fragments of organotin-based cytotoxic compounds and 4-formylbenzoic acid (FBA), covalently grafted onto the NGQDs surface. Subsequently, an in vitro determination of the therapeutic and theranostic potential of the achieved multifunctional systems was carried out. The results showed a high cytotoxic potential of the NGQDs-FBA-Sn materials against breast cancer cell line (MDA-MB-231) and a lower effect on a non-cancer cell line (kidney cells, HEK293T). Besides, thanks to their optical properties, the dots enabled their fluorescence molecular imaging in the cytoplasmatic region of the cells pointing towards a successful cellular uptake and a release of the metallodrug inside cancer cells (NGQDs-FBA-Sn).