Assessment of aqueous graphene as a cancer therapeutics delivery system

Graphene is a nanomaterial used in health and oncology settings. However, several reports have raised the alarm about potential toxicity. This study addressed this concern and determined the in vitro cytotoxicity of few-layer graphene (FLG) flakes produced in bespoke ultrasonic reactors using benign methods. The use of graphene flakes as a potential sensitising agent and a carrier for drug delivery in cancer cells was evaluated. To this end, aqueous based FLG suspensions were systematically characterised using UV-Vis, Raman spectroscopy and High-resolution Transmission electron microscopy (HR-TEM). Cell toxicity characterisation (e.g., cell viability assays using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and cell membrane integrity) of FLG in water were performed together with charge coupled device (CCD) and second harmonic generation (SHG) imaging of live cells in graphene solutions. Collectively, our findings show that NIH 3T3 mouse fibroblast and human fibroblast cells survival was higher than 80% and 90%, respectively upon treatment with the FLG fraction (~ 16 µg/ml ) recovered after centrifugation at 2000 revolutions per minute (RPM). In contrast, the cervical cancer cell line HeLa exposed to similar concentrations of FLG flakes resulted in approximately 30% cell death arguing in favour of a sensitising effect in cervical cancer cells.