Biomedical potential of the reactive oxygen species generation and quenching by fullerenes (C 60 (original) (raw)
Fullerene (C 60 ), a third carbon allotrope, is a classical engineered material with the potential application in biomedicine. One of the biologically most relevant features of C 60 is the ability to quench various free radicals, behaving as a ''free radical sponge''. Conversely, photosensitization of C 60 leads to its transition to a long-lived triplet excited state and the subsequent energy or electron transfer to molecular oxygen, yielding highly reactive singlet oxygen ( 1 O 2 ) or superoxide anion (O 2 À ), respectively. These reactive oxygen species (ROS) react with a wide range of biological targets and are known to be involved in both cellular signaling and cell damage. Therefore, the dual property of fullerenes to either quench or generate cell-damaging ROS could be potentially exploited for their development as cytoprotective or cytotoxic anticancer/antimicrobial agents. However, the attempts to that effect have been hampered by the extremely low water solubility of C 60 , and by the fact that solubilization procedures profoundly influence the ROS-generating/quenching properties of C 60 , either through chemical modification or through formation of complex nanoscale particles with different photophysical properties. We here analyze the mechanisms and biological consequences of ROS generation/quenching by C 60 , focusing on the influence that different physico-chemical alterations exert on its ROS-related biological behavior.