Quantum Dots (image) University of Washington Caption This is a cell specimen used for two rounds of testing. In the top panel, two biomarkers are stained green and red, and in the bottom, after the sample has been regenerated, the same biomarkers are stained red and green. This shows that the same tissue can be used for multiple rounds of testing without degrading the tissue sample. Credit Xiaohu Gao, University of Washington Usage Restrictions Credit required 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.