Investigation of bovine serum albumin/tropicamide interaction using a quartz crystal microbalance sensor

Abstract

This study describes the kinetics and evaluation of thermodynamic parameters of bovine serum albumin (BSA) and tropicamide (TPA) interactions, by using quartz crystal microbalance (QCM) technique, under similar physiological status. BSA was immobilized on the gold electrode surface of a QCM by using cystamine and glutaraldehyde as crosslinking agent. The immobilizing steps were followed by cyclic voltammetry technique. A flow injection analysis set-up was applied for injection of the drug solutions into the fluid system. Kinetics of the interaction was interpreted by zero- and pseudo-first-order kinetic models, depending on TPA concentration and temperature. The binding constants (k1 = 9.12, 6.55 and 6.8 mol−1 L s−1), dissociation rate constants (k−1 = 0.0028, 0.0049 and 0.0102 s−1), the binding equilibrium constant (K = 3257, 1337 and 635 mol−1 L) and the thermodynamic parameters of the interaction were estimated at different temperatures (293, 303 and 310 K, respectively). The results revealed that hydrogen bonding and van der Waals forces are the major types of interactions of between BSA and TPA.