Functional graphene derivatives for chemotherapy-based synergistic tumor therapy

Starting from simplex drug delivery system, the graphene oxide (GO) and reduced GO (rGO) materials have been developed to be "combo" nanoplatforms containing multiple therapeutic modalities, such as the targeted drug delivery, imaging, as well as photothermal therapy (PTT) due to their distinctive physical/chemical and optical properties including excellent biocompatibility, modifiable active groups, ultra-large surface area, and intense photothermal effect. The graphene-based nanoplatforms were used for the stimuli-responsive nanocarriers, showing excellent therapeutic effects activated by endogenous stimuli including low pH, overexpressed enzymes, biomolecules, elevated glutathione, and exogenous stimuli including light, magnetic/electric field, and ultrasound. More importantly, for multimodal synergistic therapy originated from the enhanced collaborative interactions among several monotherapy types, the obtained remarkable super-additive effects were not the results just through single therapy or their theoretical combination. In this review, the recent progresses of smart graphene-based nanoplatforms for integrated cancer therapy and bio-imaging are presented. Current challenges and future perspectives of graphene-based nanoplatforms in the biomedical field are also discussed.