Study on the Interaction between BSA and a Water-Soluble Cationic Poly(heteroarylene methine) Bearing Pyridinium Salts

Abstract

The interaction of BSA and a water-soluble cationic poly(heteroarylene methine) bearing pyridinium salts (WSCP) has been investigated by spectrophotometric and spectrofluorometric methods. The absorption and fluorescence spectra of BSA suggest that BSA and WSCP form a protein-polymer ground state complex due to electrostatic interaction between the negatively charged surface of BSA and the cationic side chains of WSCP. The interaction causes a decrease in fluorescence intensity of BSA due to static quenching. In addition, an enhancement in fluorescence signal of WSCP with BSA can be attributed to the surfactant property of BSA. The complex formation between BSA and WSCP results from not only electrostatic attractive force but also hydrophobic interaction, and WSCP can become a fluorescence probe for homogeneous BSA detection.