Carbon nanoparticles derived from a special oxidation of a variety of carbon rich sources are remarkably high capacity mimetics of superoxide dismutase, overcoming many limitations of conventional antioxidants while providing additional actions of considerable biological interest. Our prototype material is termed “pegylated hydrophilic carbon clusters”, or PEG-HCCs. Since most injuries, especially ischemia/reperfusion, overwhelms endogenous antioxidant protection, these materials have applicability to a wide variety of pathologies. Moreover, their chemical structure attracts them to mitochondria, where we see an ability to shuttle electrons and therefore potentially overcome genetic or acquired disorders of mitochondrial electron transport. Our current work is directed at determining their mechanism of action in order to optimize their range of favorable properties, with the immediate goal to develop a therapy for human diseases of disorders of oxidative phosphorylation. A longer range goal is to determine their effect on progressive decline in brain function due to accumulation of oxidative injury to DNA and mitochondria.