Highly Oxidized Graphene Quantum Dots from Coal as Efficient Antioxidants

Graphene quantum dots (GQDs) have recently been employed in various fields including medicine as antioxidants, primarily due to favorable biocompatibility in comparison to common inorganic quantum dots, although the structural features that lead to the biological activities of GQDs are poorly understood. Here we report that coal derived GQDs and their poly(ethylene glycol)-functionalized derivatives serve as efficient antioxidants, and we evaluate their electrochemical, chemical, and in vitro biological activity. Through the evaluation of scavenging abilities toward reactive oxygen species, we demonstrate correlation of π-conjugated stable radicals with activity.