López Duarte, IsmaelChairatana, PhoomWu, YileiPérez-Moreno, JavierBennett, Philip M.Reeve, James E.Boczarow, IgorKaluza, WojciechHosny, Neveen A.Stranks, Samuel D.Nicholas, Robin J.Clays, KoenKuimova, Marina K.Anderson, Harry L.2025-01-172025-01-172015López-Duarte I, Chairatana P, Wu Y, Pérez-Moreno J, Bennett PM, Reeve JE, et al. Thiophene-based dyes for probing membranes. Org Biomol Chem [Internet]. 2015 [citado 17 de enero de 2025];13(12):3792-802. Disponible en: https://xlink.rsc.org/?DOI=C4OB02507E1477-05201477-053910.1039/c4ob02507ehttps://hdl.handle.net/20.500.14352/114887We report the synthesis of four new cationic dipolar push-pull dyes, together with an evaluation of their photophysical and photobiological characteristics pertinent to imaging membranes by fluorescence and second harmonic generation (SHG). All four dyes consist of an N, N-diethylaniline electron-donor conjugated to a pyridinium electron-acceptor via a thiophene bridge, with either vinylene (-CH=CH-) or ethynylene (-C=C-) linking groups, and with either singly-charged or doubly-charged pyridinium terminals. The absorption and fluorescence behavior of these dyes were compared to a commercially available fluorescent membrane stain, the styryl dye FM4-64. The hyperpolarizabilities of all dyes were compared using hyper-Rayleigh scattering at 800 nm. Cellular uptake, localization, toxicity and phototoxicity were evaluated using tissue cell cultures (HeLa, SK-OV-3 and MDA-231). Replacing the central alkene bridge of FM4-64 with a thiophene does not substantially change the absorption, fluorescence or hyperpolarizability, whereas changing the vinylene-links to ethynylenes shifts the absorption and fluorescence to shorter wavelengths, and reduces the hyperpolarizability by about a factor of two. SHG and fluorescence imaging experiments in live cells showed that the doubly-charged thiophene dyes localize in plasma membranes, and exhibit lower internalization rates compared to FM4-64, resulting in less signal from the cell cytosol. At a typical imaging concentration of 1 mu M, the doubly-charged dyes showed no significant light or dark toxicity, whereas the singly-charged dyes are phototoxic even at 0.5 mu M. The doubly-charged dyes showed phototoxicity at concentrations greater than 10 mu M, although they do not generate singlet oxygen, indicating that the phototoxicity is type I rather than type II. The doubly-charged thiophene dyes are more effective than FM4-64 as SHG dyes for live cells.engjournal articlehttps://doi.org/10.1039/c4ob02507erestricted access615.31615:54Química farmaceútica23 Química