Formation of Biotinylated Alkylthiolate Self-Assembled Monolayers on Gold
C.A. Canaria, J.R. Maloney, C.J. Yu, J.O. Smith, S.E. Fraser and R. Lansford
California Institute of Technology, US
SAM, biotinylated monolayer
We demonstrate the successful formation of functional biotinylated monolayers on gold surfaces using aqueous solvents. Cyclic voltammetry (CV), alternating current voltammetry (ACV), and fluorescence microscopy have been used to characterize the films. Protein binding assays utilizing Cy3-labeled streptavidin are used to address the functionality of the monolayers. Comparison of fluorescence data between solution mixtures of alkylthiols in varied concentrations of ethanol and water solvent indicates that functional SAMs may be formed at solvent concentrations as low as 2% ethanol in water. at all solvent compositions. In addition, ACV and CV data indicate that SAMs formed in aqueous solution form faster and have less pinholes than those formed using a solvent of ethanol alone. Protein binding assays performed with Cy3-labeled streptavidin demonstrate that cleanliness of the gold substrate is imperative for the formation of quality monolayers. Samples cleaned with oxidative potentials under CV conditions exhibited higher fluorescence signals in the protein binding assays. Future experiments underway include demonstration of these SAM formations in aqueous solvents utilizing PDMS microfluidics technology.
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Nanotech 2005 Conference Program Abstract