Electrochemical and STM Studies of 1-Thio-β-d-glucose Self-Assembled on a Au(111) Electrode Surface

Abstract

In this study, a Au(111) electrode is functionalized with a monolayer of 1-thio-β-D-glucose (β-Tg), producing a hydrophilic surface. A monolayer of β-Tg was formed on a Au(111) surface by either (1) potential-assisted deposition with the thiol in a supporting electrolyte or (2) passive incubation of a gold substrate in a thiol-containing solution. For each method, the properties of the β-Tg monolayer were investigated using cyclic voltammetry (CV), differential capacitance (DC), and chronocoulometry. In addition, electrochemical scanning tunneling microscopy (EC-STM) was used to obtain images of the self-assembled monolayer with molecular resolution. Potential-assisted assembly of β-Tg onto a Au(111) electrode surface was found to be complicated by oxidation of β-Tg molecules. The EC-STM images revealed formation of a passive layer containing honeycomb-like domains characteristic of a formation of S(8) rings, indicating the S-C bond may have been cleaved. In contrast, passive self-assembly of thioglucose from a methanol solution was found to produce a stable, disordered monolayer of β-Tg. Since the passive assembly method was not complicated by the presence of a faradaic process, it is the method of choice for modifying the gold surface with a hydrophilic monolayer.

Electrochemical Properties of Lipid Membranes Self-Assembled from Bicelles

“…In this work, we have described the mechanism of bicelles adsorption onto thioglucosemodified gold electrodes. The architecture of the resulting membrane can be considered as a floating lipid membrane, which is separated from the substrate by a monolayer of hydrophilic molecules of thioglucose [26,27]. In such a configuration, the polar heads of lipids located close to the electrode surface remain hydrated and the direct interaction with metal is eliminated.…”

Thiocarbohydrates on Gold Nanoparticles: Strong Influence of Stereocenters on Binding Affinity and Interparticle Forces

“…The overlayer structure of self‐assembled monolayers (SAMs) of 1‐thio‐β‐ d ‐glucose on planar gold was previously disclosed by Kycia et al. by using scanning tunneling microscopy (STM) . Two parallel rows of the sugar molecules, one where the sulfur was located on the top, and the other where the sulfur was located on the three‐fold hollow sites of Au, were connected by hydrogen bonds.…”

Attempts to prepare tethered bilayer lipid membranes using synthetic thioglycolipid anchors: synthesis of 6″-thiotrisaccharide glycolipid analogues and applications

“…2k, 16 These analogues will have the thiol positioned at C-4 instead of C-6 so that their orientation with respect to the gold surface is similar to that of 1-β-D-thioglucose, which is known to orient perpendicular to the substrate. 17 …”