{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,5]],"date-time":"2026-05-05T00:32:31Z","timestamp":1777941151489,"version":"3.51.4"},"reference-count":35,"publisher":"Wiley","issue":"20","license":[{"start":{"date-parts":[[2025,10,18]],"date-time":"2025-10-18T00:00:00Z","timestamp":1760745600000},"content-version":"vor","delay-in-days":17,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2025,10,1]],"date-time":"2025-10-01T00:00:00Z","timestamp":1759276800000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["physoc.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Physiological Reports"],"published-print":{"date-parts":[[2025,10]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Protonation and deprotonation reactions significantly influence biological function, with buffers and transporters maintaining stable pH levels in the cytosol and various organs. However, pH can vary considerably in organ lumens, such as the airway surface liquid (ASL), which serves as a defense barrier for airways. Traditional microelectrodes, while precise, face limitations prompting the use of fluorescent pH sensors. Although many green fluorescent protein (GFP)\u2010based pH sensors have been reported, data are usually limited to their spectral properties. Photophysical properties are often reported for a single pH value. In this study, the photophysical properties of pHluorins and superfolder GFP\u2014including a novel pH sensor pHluorin4\u2014were compared. Purified pHluorin4 effectively reported ASL pH differences in cystic fibrosis (CF) and non\u2010CF epithelia. These findings provide a comprehensive summary of the photophysical and spectral properties of popular pHluorins, including the new member pHluorin4, which can be used to optimize their application in different systems.<\/jats:p>","DOI":"10.14814\/phy2.70625","type":"journal-article","created":{"date-parts":[[2025,10,18]],"date-time":"2025-10-18T12:54:27Z","timestamp":1760792067000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["The\n                    <scp>pH<\/scp>\n                    \u2010dependent photophysical and spectral properties of\n                    <scp>pH<\/scp>\n                    \u2010sensing green fluorescent proteins"],"prefix":"10.14814","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5535-2925","authenticated-orcid":false,"given":"Ian M.","family":"Thornell","sequence":"first","affiliation":[{"name":"Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine University of Iowa  Iowa City Iowa USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2025,10,18]]},"reference":[{"key":"e_1_2_10_2_1","doi-asserted-by":"publisher","DOI":"10.1172\/jci.insight.121468"},{"key":"e_1_2_10_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jsb.2016.01.016"},{"key":"e_1_2_10_4_1","doi-asserted-by":"publisher","DOI":"10.1152\/ajpcell.1988.255.6.C844"},{"key":"e_1_2_10_5_1","doi-asserted-by":"publisher","DOI":"10.1126\/science.1223012"},{"key":"e_1_2_10_6_1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.93.16.8362"},{"key":"e_1_2_10_7_1","doi-asserted-by":"publisher","DOI":"10.1152\/ajplung.00027.2015"},{"key":"e_1_2_10_8_1","doi-asserted-by":"publisher","DOI":"10.1021\/bi00056a003"},{"key":"e_1_2_10_9_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.chembiol.2020.02.004"},{"key":"e_1_2_10_10_1","doi-asserted-by":"publisher","DOI":"10.1021\/bi00866a011"},{"key":"e_1_2_10_11_1","article-title":"Double\u2010barreled and concentric microelectrodes for measurement of extracellular ion signals in brain tissue","volume":"103","author":"Haack N.","year":"2015","journal-title":"Journal of Visualized Experiments"},{"key":"e_1_2_10_12_1","doi-asserted-by":"publisher","DOI":"10.1021\/jp0362077"},{"key":"e_1_2_10_13_1","first-page":"115","article-title":"An in\u00a0vitro model of differentiated human airway epithelia. 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