IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Biomaterials Tuesday Sessions
       Session BI-TuP

Paper BI-TuP13
Role of Interfacial Water Structure on the Protein Resistant Properties of Oligo(ethylene glycol) Monolayers

Tuesday, October 30, 2001, 5:30 pm, Room 134/135

Session: Surface Characterization and Non-Fouling Surfaces Poster Session
Presenter: B. Subramanian, The University of New Mexico
Authors: B. Subramanian, The University of New Mexico
J. Yan, The University of New Mexico
G.P. Lopez, The University of New Mexico
Correspondent: Click to Email
Understanding the mechanism of protein adsorption at surfaces is an important issue in the field of biomedical materials, cellular adhesion and clinical diagnostics. Self-assembled monolayers (SAMs) of oligo(ethylene glycol)-terminated alkanethiols on gold are known to be protein resistant and represent a good model system to study the interactions of proteins with organic surfaces. Although these SAMs are resistant to protein adsorption, the mechanism by which these monolayers prevent protein adsorption is not yet established. Recently, it was suggested that protein resistance of these monolayers is a consequence of the formation of a structured interfacial water layer, which prevents direct contact between the surface and the protein. It was further suggested that, this might be a common mechanism for other monolayers, which show resistant to protein adsorption. It has been observed that, interfacial water undergo sharp changes in its properties (e.g., density, surface viscosity) at 15, 30, 45, and 60°C. These changes are attributed to the change in the structure of interfacial water at that temperature. We examine whether the change in the interfacial water structure at these characteristic temperatures affect the protein resistant properties of these monolayers, by carrying out protein adsorption on mixed monolayers of hexa(ethylene oxide)-terminated alkanethiols and methyl terminated alkanethiol (@chi@ @sub EG6@ = 0.44) as a function of temperature. The results show that, there is a sharp change in the protein adsorption behavior at 30±1°C. Below this temperature, there is no protein adsorption and above this temperature there is approximately a monolayer of protein adsorbed on the SAM surfaces. These results strongly support the view that interfacial water structure plays an important role in the protein resistant properties of oligo(ethylene glycol) SAMs.