Intracellular pH Sensing (IMAGE) Naval Research Laboratory Caption Fluorescent micrographs collected from COS-1 cells co-injected with 550 nm emitting QD-dopamine conjugates and red FLX internal standard nanospheres in buffer at pH 6.5. The growth media was switched to pH 11.5 supplemented with the drug Nystatin and micrographs were captured at the indicated time intervals from both the QD and FLX emission channels. Merged images are shown in the bottom row and pH values extracted at each time interval are shown below. Credit Naval Research Laboratory/Scripps Research Institute 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.