Peer-Reviewed Journal Details
Mandatory Fields
Dalfen, Irene; Dmitriev, Ruslan I.; Holst, Gerhard; Klimant, Ingo; Borisov, Sergey M.
Analytical Chemistry
Background-free fluorescence decay time sensing and imaging of pH with highly photostable diazaoxotriangulenium dyes
Optional Fields
Decay time FRET pH sensor Triangulenium Photoinduced electron transfer Frequency Domain FLIM
Novel fluorescent diazaoxatriangulenium (DAOTA) pH indicators for lifetime-based self-referenced pH sensing are reported. The DAOTA dyes were decorated with phenolic receptor groups inducing fluorescence quenching via photoinduced electron transfer mechanism. Electron-withdrawing chlorine substituents ensure response in the most relevant pH range (apparent pKa values ~5 and 7.5 for the p,p-dichlorophenol- and the p-chlorophenol-substituted dyes, respectively). The dyes feature long fluorescence lifetime (17-20 ns), high quantum yield (~60%) and high photostability. Planar optodes are prepared upon immobilization of the dyes into polyurethane hydrogel D4. Apart from the response in the fluorescence intensity, the optodes show pH-dependent lifetime behaviour which makes them suitable for studying 2D pH distribution with help of fluorescence lifetime imaging technique. The lifetime response is particularly pronounced for the sensors with high dye concentration (0.5-1% wt. in respect to the polymer) and is attributed to efficient homo-FRET mechanism.
Grant Details