Protein adsorption on amino-acid-conjugated self-assembled molecule-modified SiO₂ surfaces

Protein adsorption has a crucial effect on biocompatibility during the interaction of biomaterial surfaces and the biological environment. It is significant to understand and control the interactions among biomaterials and proteins for several biomedical applications. Surface engineering plays a significant role in determining biocompatibility by tuning the effects directly on proteins. In this study, amino acid (histidine and leucine) conjugated self-assembled molecules were synthesized and used to modify silicon dioxide (SiO₂) surfaces to investigate protein adsorption behavior. Silicon dioxide surfaces were modified with (3-aminopropyl)triethoxysilane-conjugated histidine and leucine amino acids. Modified silicon dioxide surfaces were characterized by water contact angle measurements and X-ray photoelectron spectroscopy analysis. Protein adsorption (human serum albumin, fibrinogen and immunoglobulin G) on silicon dioxide-coated crystals was investigated in situ by using a quartz crystal microbalance (QCM) biosensor. From the results, model proteins showed different selectivities to the amino-acid-conjugated silicon dioxide-coated crystals depending on the type of the amino acid and concentration. Consequently, this controlled chemistry on the surface of biomaterials has a great potential to manipulate protein adsorption and enhance the biocompatibility of biomaterials for various biomedical applications.