Silicone-protein films: Establishing the strength of the protein-silicone interaction

Protein-on-silicone and silicone-on-protein films were prepared using either trimethylsilyl-terminated (unfunctionalized, PDMS) or (triethoxysilyl)propyl-terminated (functionalized, TES-PDMS) silicones and human serum albumin (HSA). The films were exposed to aqueous solutions of different pH's or containing SDS. X-ray photoelectron spectroscopy (XPS) and contact-angle measurements (CA) were used to characterize the resulting surfaces. The film formed by coating a protein surface with TES-PDMS showed much slower protein desorption kinetics than the other slides upon challenge by SDS, acidic, neutral, or basic aqueous solutions. This observation may be understood to arise from the cross-linking of TES-PDMS using the protein as a template, resulting in intimate contact between the two polymers.