Benzimidazole-based ratiometric two-photon fluorescent probes for acidic pH in live cells and tissues.
Many aspects of cell metabolism are controlled by acidic pH. We report a new family of small molecule and ratiometric two photon (TP) probes derived from benzimidazole (BH1-3 and BH1L) for monitoring acidic pH values. These probes are characterized by a strong two-photon excited fluorescence, a marked blue-to-green emission color change in response to pH, pKa values ranging from 4.9 to 6.1, a distinctive isoemissive point, negligible cytotoxicity, and high photostability, thereby allowing quantitative analysis of acidic pH. Moreover, we show that BH1L optimized as a lysosomal-targeted probe allows for direct, real-time estimation of the pH values inside lysosomal compartments in live cells as well as in living mouse brain tissues through the use of two-photon microscopy. These findings demonstrate that these probes will find useful applications in biomedical research.
Division of Energy Systems Research, Ajou University , Suwon 443-749, Korea.
Hyung Joong
HJ
Kim
Cheol Ho
CH
Heo
Hwan Myung
HM
Kim
D000143:Acids / Q000032:analysis; D000818:Animals; D001562:Benzimidazoles / Q000032:analysis*; D001923:Brain Chemistry; D005456:Fluorescent Dyes / Q000032:analysis*; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D051379:Mice; D036641:Microscopy, Fluorescence, Multiphoton; D017207:Rats, Sprague-Dawley; D013050:Spectrometry, Fluorescence
D000143:Acids; D001562:Benzimidazoles; D005456:Fluorescent Dyes; C031000:benzimidazole