Spectral Investigations of Inclusion Complexes of a Fluorescein Bifluorophore with α-, β-, and γ-Cyclodextrins

Abstract

The formation of inclusion complexes of the (6-FAM)₂ bifluorophore with α-, β-, and γ-cyclodextrins in phosphate buffer solution (pH 9.0) was studied by spectrophotometry and fluorimetry. The association constants and Gibbs free energy changes for 1:1 stoichiometry was determined. The highest association constant was observed for the complex with β-cyclodextrin, which was explained by the optimal spatial match between the guest molecule and the host cavity. The effect of the (6-FAM)₂/β-CD inclusion complex on the fluorescent response of the system in the presence of protein (bovine serum albumin) was shown.