Biofunctionalization of Nanoelectrode Ensembles: Protection of the Nanoelectrodes with Self-assembled Monolayers

Abstract

In this work we study the possibility to use self-assembled monolayers (SAMs) of thiols to protect the surface of nanoelectrodes ensembles (NEEs) from the undesired adsorption of biomolecules, in particular, proteins. Thioctic acid (TA) and 2-mercaptoethanesulfonic acid (MES) were chosen for this aim. The behaviour of SAM-modified NEEs was studied by cyclic voltammetry as a function of the solution pH using ferrocenecarboxylate as anionic redox probe (FcCOO-) and (ferrocenylmethyl) trimethylammonium (FA+) as cationic redox probe. It was observed that, when the SAM is negatively charged it repels the negative redox probes from the surface of the nanoelectrodes, while the voltammetry of FA+ remain unchanged. The possible protective role of the SAM was confirmed by studying the voltammetric signals recorded with NEEs dipped in a solution of a high adsorbable protein, namely casein, comparing signals recorded at bare NEEs vs. signals at SAM-modified NEEs, in different experimental conditions.

New Insights on the Interaction between Thiophene Derivatives and Au Surfaces. The Case of 3,4-Ethylenedioxythiophene and the Relevant Polymer

“…In the case of SO3-EDOT, this band is absent, suggesting once more the release of the ether moiety. As a control experiment, a simple thiol molecule, namely, MESNa, has been adsorbed on the Au surface in the same experimental conditions; the molecule has been selected taking into account that it is well-known that the molecule is intact on the surface after the adsorption. , In this case, the C–SO 3 – stretching band is well evident in the Raman spectra (inset in Figure c).…”