CHARCOAL 2 (IMAGE) Rice University Caption Artificial enzymes made of charcoal nanoparticles heavily oxidized with fuming nitric acid (HNO3) could have the power to quench superoxides, toxic radical oxygen ions that appear at high concentrations in organisms after an injury. Credit Tour Group/Rice University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.