Specific Immobilization of Streptavidin on Mixed Self-Assembled Monolayers as Mixing Ratio

Abstract

We report on the distribution of mixed self-assembled monolayers (SAMs) composed of biotinylated and diluent alkylthiolates for streptavidin immobilization. Two thiol derivatives, 11-mercapto-1-undecanol (MUOH) and 11-mercaptoundecanoic-(8-biotinylamido-3,6-dioxaoctyl) amide (MBDA), were employed for mixed SAM. These thiols formed self-assembled monolayer without local domain, and streptavidins were immobilized onto biotinylated gold surface without nonspecific binding. In order to find the optimized condition of immobilization of streptavidin, we controlled the mixing ratio of two kind thiols by colorimetric detection assay, and the immobilization was characterized by atomic force microscopy (AFM), scanning tunneling microscopy (STM), and ellipsometer.

Effects of Composition of Oligo(ethylene glycol)-Based Mixed Monolayers on Peptide Grafting and Human Immunoglobulin Detection

“…Even though fundamental studies involving OEG-based monolayers have been reported as early as 1991 by Prime and Whitesides, related applications only began in the past decade. Alkanethiols with terminal carboxylate (−COOH) groups have been widely used in pure or mixed monolayers, and OEG-based alkylthiolates (SH–(CH 2 ) m –EG n COOH) have been recently characterized for biosensing purposes. − Mixed SAMs based on linear alkanethiols with small molecular variations in termini have been studied for biosensing and other applications. − Recently, studies have been carried out with mixed OEG-based alkanethiol monolayers. ,,,− The structure and properties of the mixed monolayers have an effect on the ligand immobilization and, in turn, on subsequent sensing properties. Properties of sets of mixed monolayers will not be necessarily similar when the terminal functional groups are changed .…”