QCM-D Study of α-lactalbumin Adsorption on Stainless Steel surface coated with Poly ethylene glycol (PEG) Nanofilms

In this study, the ability of stainless steel surface coated with poly(ethylamine) (PEI) / silicate grafted PEG nanofilms to hinder the adsorption of α-lactalbumin has been investigated. The modified stainless steel surface has been designed by varying the anchor film and PEG molecular weight and concentration. The modification of the stainless steel surface and protein adsorption had been done and monitored in-situ by Quartz Crystal Microbalance with Dissipation (QCM-D). The adsorption of α-lactalbumin was also performed on the bare stainless surface as a control. The adsorption was conducted at 23°C and pH 7.2. The results showed that the stainless steel surface coated with PEI-PEG nanofilms has capability to reduce the adsorption of α-lactalbumin up to 89 %. However, surprisingly, the adsorption of α-lactalbumin was higher on the stainless steel surface coated with silicate-PEG nanofilms than that on the bare stainless steel surface. The study indicates that both anchor film and PEG film are important factors to be looked at during designing a protein-inert surface.