| 초록 |
Protein adsorption onto the artificial surface is the initial event that occurs when a surface comes into contact with the living fluid such as blood. In the protein adsorption, the intrinsic properties of surface and protein are essential factors and these properties could affect the molecular interaction between protein and surface. Furthermore, the structure of water in contact with a surface directly controls the biological response such as protein adsorption. Here we studied the role of water structure on molecular interaction between protein and artificial surfaces. The proteins were covalently immobilized onto the AFM tip and the molecular interaction between the immobilized proteins and the various surfaces was measured in water media by using a AFM. Firstly, we investigated the molecular force depending on the water wettability of the water-contacting surfaces. It was observed that significant change in molecular force occurs near the surface at θ ≒ 65°, which is presumably due to the change of interfacial water structure and the binding force of water to the surface at this critical contact angle. Secondly, we compared hydrophobic interaction and electrostatic interaction in water media, and the results show that hydrophobic interaction is higher than electrostatic interaction due to the different water structure around the surfaces. Finally, the temperature dependence of molecular force of the protein to poly(N-isopropylacryamide) brush was investigated. It is suggested that the rapid change of molecular force around transition temperature is mainly due to the different structure of bound water around the Pnipaam chains. |
