Nuclei Overlap (2 of 3) (IMAGE) University of Warwick Caption The purple stain for cancer cell nuclei overlaps perfectly with the emission of green light from the iridium-albumin conjugate, showing the protein has delivered the photosensitizer to the nucleus of cancer cells. 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.