(hydrophobic) surface with a PEG brush can be effective in preventing or retarding the adsorption of proteins at the surface and suppressing deposition of biological cells

Adsorption of proteins onto a solid surface is believed to be the initial and controlling step in biofouling. A better knowledge of the fouling process can be obtained by controlling the formation of the first protein layer at a solid surface. A number of methods have been investigated to inhibit adsorption of proteins. In this study, the adsorption kinetics of -casein onto bimodal PEG brushes on a stainless steel surface has been studied by means of a quartz crystal microbalance with dissipation (QCM-D). Bimodal brushes consist of long and short PEG chains were prepared in situ using a physisorption method. The adsorption kinetics of -casein were monitored with different PEG combinations and concentrations. -casein adsorptions onto monomodal PEG brushes were determined for comparison. -casein adsorption was also studied on a bare stainless steel surface as a control. All adsorptions were conducted at 23 C and pH 7.2. The results obtained showed that depositing PEG from solutions with increasing concentrations from 0.1 to 5.0 g / L decreased adsorption of -casein by about 40% on monomodal surfaces. Bimodal PEG surfaces appeared to be less effective than monomodal PEG brushes surfaces in preventing adsorption of casein. It is suggested that bimodal PEG surfaces behave like a ‘solid’ which leads to -casein adsorption at the surface via hydrophobic interaction for this observation. The difference between PEG combinations in suppressing the adsorption of -casein was not very significant, indicating the existence of an optimal value of chain density to effectively suppress the adsorption of -casein. Keywords— -casein, QCM-D, stainless steel, bimodal brush, PEG