259746-77-5Relevant academic research and scientific papers
Novel mono-cationic fluorescent probes based on different central π-conjugated bridges for two-photon bioimaging of cellular nuclei
Chi, Shuheng,Li, Liang,Wu, Yiqun
, p. 69748 - 69757 (2016)
A series of novel pyridine mono-cationic two-photon fluorescent probes based on different central π-conjugated bridges, fluorenone (W-pyI), dibenzothiophene (S-pyI), and dibenzofuran (F-pyI), were prepared and studied. Under one-photon excitation in a N,N-dimethylformamide solution, W-pyI, S-pyI, and F-pyI displayed fluorescence quantum yields of 0.401, 0.425, and 0.09, respectively. The two-photon fluorescence performance indicated that these probes possessed two-photon absorption cross-sections of 681 GM (W-pyI), 630 GM (S-pyI), and 620 GM (F-pyI) at 800 nm femtosecond laser excitation. The luminance "turn-on" effect of W-pyI, S-pyI, and F-pyI bonding with calf thymus DNA in Tris-HCl buffer solutions displayed 58-fold, 30-fold, and 25-fold fluorescence quantum yield increments, respectively, and 350-450% two-photon absorption cross-section enhancement. The confocal fluorescence imaging showed clear one- and two-photon fluorescence imaging. The mean co-localization coefficients between these probes and Hoechst 33342 in 3T3 cells ranged from 0.89-0.92, indicating that they showed excellent nuclear targeting abilities. The counterstaining experiments showed these probes possessed good counterstaining compatibility and membrane permeability in the application of multicolor targeting. A time-dependent fluorescence intensity test under continuous femtosecond laser irradiation showed that W-pyI possessed a longer observation time (3000 seconds) and a lower fluorescence attenuation amplitude (7.1%) in the first 300 seconds than S-pyI, F-pyI and other previously reported pyridinium derivatives, demonstrating that the central π-conjugated bridge "fluorenone" played a key role in improving photostability during probe designing for two-photon bioimaging applications.
