Determination of the binding constants of nanomarkers of the fluorescein family to human serum albumin

Using three models, the constant of quenching of fluorescence of nanomarkers of the fluorescein family and the actual constants of its binding to human serum albumin (HSA) at different values of pH are determined. The presence of two mechanisms of binding of nanomarkers of the fluorescein family to HSA and anti-cooperativity are shown. The dependence of the constants of the quenching fluorescence of nanomarkers on pH was found: for fluorescein this was nonlinear, for its halogen derivatives (erythsosine, eosin, and Rose Bengal) it was monotonous and decreased with an increase of pH. It is shown that the electronegativity of the atoms in the structural formulas of nanomarkers of the fluorescein family influences the values of the constants of binding of nanomarkers to HSA.