Light activating an Iridium Catalyst (IMAGE) University of Warwick Caption Visible light can activate an iridium (large purple ball) catalyst which has a special coating (gray balls) which homes in on coenzyme NADH (red/gray/purple balls at bottom) in cancer cells and removes an electron from it, so destroying them by cutting off a vital energy source and generating a toxic form of oxygen (in the blue bubble). Credit Designed by Huaiyi Huang at Sun Yat-Sen University Usage Restrictions Use only with credit. 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.