Quartz Crystal Microbalance Study of Protein Adsorption on Chitosan, Chitosan/Poly(vinyl pyrrolidone) Blends and Chitosan-graft-Poly(vinyl pyrrolidone) Surfaces

Abstract

Adsorption behaviour of bovine serum albumin (BSA) onto chitosan (CS), chitosan/poly(vinyl pyrrolidone) blends (CS/PVP blends), and chitosan- graft-poly(vinyl pyrrolidone) (CS- graft-PVP) surfaces were investigated using quartz crystal microbalance (QCM). The adsorbed quantities of protein on the three surfaces were examined and were found to decrease in the following order: CS > CS/PVP blends > CS- graft-PVP. The kinetics of BSA adsorption in the early stage was analysed. The Langmuir isotherm model was used to describe the BSA adsorption behaviour on CS and its derivates. The attachment, detachment rate constants, and the association constants ( Ka ) were of the same order of magnitude, whereas the Ka for BSA on CS- graft-PVP surface was the lowest of the three surfaces. The adsorbed protein layer structure was also estimated. For CS- graft -PVP, most of the proteins adsorbed on the surface were of side-on structure, whereas for CS only about 40% of the proteins were of side-on structure.