Fluorescent Probes To Detect pH (IMAGE) Michigan Technological University Caption Haiying Liu's acid-sensitive luminescent probe glows progressively brighter in living cells as the pH decreases, both under conventional fluorescence (CF) and under single-photon upconversion luminescence (FUCL). Credit Haiying Liu/Michigan Tech 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.