Spectroscopic investigations of interaction of fluorescent nanomarkers of fluorescein family with human serum albumin at different values of pH

This work is dedicated to investigation of interaction of nanomarkers of fluorescein family (initial composition – fluorescein and its halogens-derivatives – erythrosin and eosin) with human serum albumin (HSA) at different values of pH. Were detected differences in polarization of fluorescence of nanomarkers, in parameters of rotational diffusion of nanomarkers, in binding mechanisms of nanomarkers to HSA, in change of secondary structure of HSA at binding of nanomarkers, in effective Stern–Volmer constants of quenching of fluorescence of nanomarkers, which are determinated by value of electronegativity of atoms of nanomarkers. The increase of electronegativity of atoms in nanomarkers leads to increase of polarization of its fluorescence, to decrease of its coefficient of rotational diffusion, to increase of its time of rotational relaxation, to increase of Einstein’s effective radius of nanomarkers, to decrease of effective Stern–Volmer constants of quenching of fluorescence of nanomarkers in range from pI of HSA (4.7) to physiological pH (7.4).