Binding of Biotin to Gold Surfaces Functionalized by Self-Assembled Monolayers of Cystamine and Cysteamine: Combined FT-IRRAS and XPS Characterization.
As part of our project of developing a new IR-based immunosensor, we investigated the functionalization of gold substrates with thin organic films containing biotin ligands. A two-step procedure was developed consisting of the chemisorption of short amine-terminated organosulfur compounds, followed by their reaction at the solid liquid interface with an activated ester derivative of biotin. Covalent binding of biotin to these attachment layers was assessed by Fourier transform infrared reflection-absorption spectroscopy (FT-IRRAS) and X-ray photoelectron spectroscopy (XPS). The interaction of activated biotin with alcohol- and carboxylic acid-terminated monolayers was also investigated, and, as expected, no binding occurred. Moreover, mixed layers of short alcohol- and amine-terminated thiolates were successfully constructed at the gold surfaces and were shown to be the most efficient for the covalent binding of biotin thanks to the blocking effect of the thioalcohol, which prevented direct adsorption of biotin to the gold surface. Copyright 2001 Academic Press.
Yam
Chi-Ming
CM
Laboratoire de Physico-Chimie des Surfaces, UPRESA 7045, Ecole Nationale Supérieure de Chimie de Paris, 11, rue Pierre et Marie Curie, Paris Cedex 05, F-75231, France
Pradier
Claire-Marie
CM
Salmain
Michèle
M
Marcus
Philippe
P
Jaouen
Gérard
G