The adsorption of large biomolecules such as proteins is of high relevance in medicine; adsorbed proteins can initiate undesirable biological reactions such as blood coagulation or immune responses, which adversely affect the human body and the functioning of medical devices. Thus, the suppression of protein adsorption onto material surfaces is essential for medical and biomedical applications. Interfacial water molecules may play a key role in protein adsorption. In this context, in this study, we prepare various types of surfaces (hydrophobic, hydrophilic, anionic, cationic, and zwitterionic) using polymer brushes with different molecular structures. We analyze the adsorption of negatively and positively charged proteins using a quartz crystal microbalance (QCM) to quantitatively investigate protein adsorption onto the polymer brush surfaces. The structure of the interface between the polymer brushes and water media is investigated using sum frequency generation (SFG) spectroscopy. Our comparison of the protein adsorption characteristics with the properties of the interfacial water molecules of each polymer brush indicates that the interfacial water molecules, which strongly interact with polymer brushes, are important for suppressing protein adsorption. The findings can significantly contribute to the functional biomaterial design.

Adsorbed proteins initiate the undesirable phenomena like blood coagulation and immune response, and lead to the negative effects on human body and function of biodevices. Thus, the suppression of protein adsorption is essential property for biomaterials. Therefore, interfacial water molecules may play a key role on protein adsorption. In this study, various types of surface ; hydrophobic, hydrophilic, anionic, cationic and zeitterionic were prepared by high-density polymer brush having different molecular structure. The amount of adsorbed negatively and positively charged protein was analyzed by quartz crystal microbalance (QCM) method to investigate the protein adsorption on polymer brush surfaces quantitatively. Structure of interfacial water at the interface between polymer brush and water media was investigated using sum-frequency generation (SFG) spectroscopy. From the quantitative comparison with protein adsorption and structure of interfacial water molecule of each polymer brush, it is concluded that the interfacial water molecules, which form strong hydrogen bonding is a strong relation to the suppression of protein adsorption.