Heng, S.Reineck, P.Vidanapathirana, A.Pullen, B.Drumm, D.Ritter, L.Schwarz, N.Bonder, C.Psaltis, P.Thompson, J.Gibson, B.Nicholls, S.Abell, A.2017-12-122017-12-122017ACS Omega, 2017; 2(9):6201-62102470-13432470-1343http://hdl.handle.net/2440/109962Data source: Supporting information, https://doi.org/10.1021/acsomega.7b00923Biologically compatible fluorescent ion sensors, particularly those that are reversible, represent a key tool for answering a range of fundamental biological questions. We report a rationally designed probe with a 6′-fluoro spiropyran scaffold (5) for the reversible sensing of zinc (Zn2+) in cells. The 6′-fluoro substituent overcomes several limitations normally associated with spiropyran-based sensors to provide an improved signal-to-background ratio and faster photoswitching times in aqueous solution. In vitro studies were performed with 5 and the 6′-nitro analogues (6) in HEK 293 and endothelial cells. The new spiropyran (5) can detect exogenous Zn2+ inside both cell types and without affecting the proliferation of endothelial cells. Studies were also performed on dying HEK 293 cells, with results demonstrating the ability of the key compound to detect endogenous Zn2+ efflux from cells undergoing apoptosis. Biocompatibility and photoswitching of 5 were demonstrated within endothelial cells but not with 6, suggesting the future applicability of sensor 5 to study intracellular Zn2+ efflux in these systems.en© 2017 American Chemical Society. This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.Biocompatible materials; cell and molecular biology; electric properties; electromagnetic wave; fluorescence; fluorescence microscopy; luminescence spectroscopy; optical materials; spectraJournal article003007664410.1021/acsomega.7b009230004187155000922-s2.0-85030167749371957Vidanapathirana, A. [0000-0003-0126-799X]Pullen, B. [0000-0001-9718-5088]Ritter, L. [0000-0001-5942-851X]Bonder, C. [0000-0001-9875-967X]Psaltis, P. [0000-0003-0222-5468]Thompson, J. [0000-0003-4941-7731]Nicholls, S. [0000-0002-9668-4368]Abell, A. [0000-0002-0604-2629]