Abstract:

Polysaccharide surfaces were constructed from carrageenan and poly(diallyldimethylammonium chloride)(PDDA) via layer-by-layer assembly technique. The adsorption of bovine serum albumin(BSA), an ellipsoidal model protein, on the surface of the multilayers was studied in detail by means of a quartz crystal microbalance with dissipation monitoring(QCM-D). Four carrageenans with different charge densities were investigated, and the amount of the carrageenan assembled was found to decrease with the increase of the charge density. When BSA was adsorbed on the PDDA surface, the dissipation factor(ΔD) was small, indicating that BSA lay down on the surface to form a thin layer. When BSA was adsorbed to the ι-carrageenan(IC) surface, both the QCM frequency shifts(ΔF) and the dissipation factor ΔD were larger, suggesting that BSA stood on the carrageenan surface to form a thicker layer. In addition, it was found that both the amount of adsorption and the packing of BSA on the carrageenan surface depended on the charge density and the surface roughness of the carrageenan substrate.

Key words: Quartz crystal microbalance (QCM-D), protein, polyssacharide