Polarized fluorescence parameters of FAD excited at 355 and 450 nm in water-propylene glycol solutions

Abstract

Flavin adenine dinucleotide (FAD) is important endogenous fluorophore that play an essential role in cellular respiration and are widely used as fluorescent biomarkers for investigation of metabolic processes in cells and tissues. In solutions FAD can exist in two conformations: “open”, where the isoalloxazine and adenine moieties are well separated, and “folded”, where they are located close to each other and the π-π stacking interaction occurs. In this work we studied fluorescence anisotropy kinetics measured by TCSPC of FAD excited at 355 and 450 nm in water-propylene glycol(PG) solutions.
At brief, FAD was dissolved in water-PG solution at concentration 60 µM and excited by vertically polarized laser impulses at 355 nm (400ps, 4kHz) or 450 nm (30 ps, 1 MHz). FAD fluorescence was detected at 530 nm at the right angle to the laser beam. Vertical and horizontal polarization components were recorded, and then all fluorescence parameters were obtained by global fit. Water-PG solutions at the concentrations of 0%, 20%, 40%, 60%, 80% and 98% were used in experiment. The results are quite similar for both excitation wavelengths. It was found that there are two fluorescence decay times and one rotational diffusion time. In water solutions fluorescence decay times contribution in total signal is nearly the same while with the raise of PG concentration demonstrated domination of the contribution of longer decay time. The rotational diffusion time manifested a sharp rise, up to forty times with PG concentration practically in proportion to the solution viscosity.

Speaker

Beltukova Dina Mikhailovna
Ioffe Institute, Polytekhnicheskaya, 26, St. Petersburg, Russia
Russia

Report

File with report

Discussion

Ask question