Self-Assembled Carbohydrate Monolayers: Formation and Surface Selective Molecular Recognition

Abstract

The formation of self-assembled monolayers (SAMs) of representative thiocarbohydrate derivatives onto a gold surface has been investigated to build an artificial carbohydrate scaffold to mimic non-bonded molecular recognition phenomena. Three types of carbohydrate SAMs were formulated from (i) 1-β-d-thioglucose (1), (ii) 1-β-d-thioglucose tetraacetate (2), and (iii) 2-mercaptoethyl α-d-mannopyranoside (3). Subsequently, each SAM was spectroscopically characterized by reflection-absorption infrared spectroscopy (RAIRS). Deprotection of the acylated carbohydrate SAM was achieved in situ, indicating that chemical transformation may be performed without disruption of the sulfurgold bond. With the mannose derivative, in which the carbohydrate moiety was separated from the gold surface by the spacer unit OCH2CH2SH, it was possible to demonstrate that such a carbohydrate SAM was able to interact selectively with a specific carbohydrate binding protein, i.e., concanavalin A (Con A). Exposure of the mannose derive...