Study of the Interaction between a Water-soluble Cationic Fluorescent Conjugated Polymer and Bovine Serum Albumin

The interaction between a water-soluble cationic fluorescent conjugated polymer (WCFP) and bovine serum albumin (BSA) was studied using UV–Vis absorption, fluorescence and circular dichroism spectroscopies. The results show that the fluorescence of BSA is strongly quenched by the WCFP under physiological conditions (pH = 7.4). The quenching mechanism was found to be static, which was confirmed by the quenching rate constant (Kq) and UV–Vis absorption spectra. The thermodynamic parameters (∆Hθ, ∆Sθ and ∆Gθ) calculated from the complexation constant, determined according to Lineweaver–Burk equations are 38.6 kJ·mol−1, 228 J·mol−1·K−1 and −29.4 kJ·mol−1 at 298 K. The principal interaction was proposed to be electrostatic.