Fullerene Nanorings as Nitric Oxide Radical Scavengers for Ultraviolet-Induced Cellular Injury

Abstract

Nitric oxide radical (NO•) induced by UV irradiation would exacerbate cellular damage and apoptosis. Though fullerenes are known as excellent radical scavengers, severe aggregation and poor bioavailability often decrease their antioxidant capability in real bioapplications. Herein, a simple but effective method is introduced for the synthesis of a novel hollow fullerene nanostructure (fullerene nanoring, FNR). C60 aggregations produced in m-xylene/isopropyl alcohol (IPA) binary solvents by liquid–liquid interface precipitation strategy are chemically etched by the addition of ethylenediamine (EDA), while aminofullerenes subsequently nucleate at the interface of short-lived EDA-IPA droplets. Careful control of the nucleation kinetics via fine-tuning of the xylene/IPA ratio proved critical for the successful formation of ring-shaped FNR. Such hydrophilic and low-cytotoxic nanostructures possess surprisingly outstanding scavenging performance toward NO• (IC50 = 80 μg/mL). Prominent cytoprotection of FNR against UV-induced DNA oxidation and cellular injury is further confirmed by laser confocal microscopy and flow cytometry. Our results may benefit the upgradation of nanocarbon materials for bioapplications