Nuclei Overlap (1 of 3) (IMAGE) University of Warwick Caption Iridium with its organic coat which is hooked up to the protein albumin (HSA). Together that enter cancer cells and deliver the iridium photosensitizer to the nucleus. On irradiation with blue light, the iridium not only glows green, but converts oxygen in the cell to a toxic form called triplet oxygen, which kills the cell. Credit University of Warwick Usage Restrictions Only to be used in conjunction with this story. 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.