(120g) Chemical Modifications Of Inert Self-Assembled Monolayers With Oxygen Plasma For Biosensor Applications

In this presentation we report a new approach to chemically modify inert self-assembled monolayers (SAMs) with oxygen plasma and generated functional groups which permit the immobilization of protein human IgG on the surface for biosensor applications. Detailed surface modification and protein immobilization were characterized by using ellipsometry, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy and fluorescence microscopy. The covalent attachment of IgG to the surface is possibly through the formation of Schiff base between the aldehyde functional groups generated in situ from the oxygen plasma treatment and the amine functional groups of proteins. However, only 1 to 2 s of treatment time is required to modify the surface of the SAMs. Longer treatment time will result in the etching of the SAMs and no protein can be immobilized on the surface. This approach may provide a new means of introducing functional groups to the inert SAMs and avoid the use of bifunctional linkers for protein immobilization.