Chemical modification of gold electrodes via non-covalent interactions

Abstract

Chemically modifying electrode surfaces with redox active molecular complexes is an effective route to fabricating tailored functional materials.

Artificial photosynthesis: opportunities and challenges of molecular catalysts

“…A molecular catalyst functionalized with sulfur groups can be easily grafted on an Au electrode ( Fig. 39c), 574,575 which, like the glass carbon (GC) electrode, is a classic planar substrate electrode for investigating the monomolecular layer. There are several conventional strategies for the modification of the GC electrode via covalent attachment, i.e., the ''click'' reaction route, 576,577 diazonium reduction route, 376,[578][579][580] and methods designed by combining these two routes (Fig.…”

Immobilization Techniques for Aptamers on Gold Electrodes for the Electrochemical Detection of Proteins: A Review

“…In the same way, pyrene-labeled PEG can be bound to the rGO interface to provide a biosensor with excellent antifouling properties [23,24,148,162,[165][166][167]. The noncovalent attachment of aromatic complexes does not strictly rely on the utilization of graphene; instead, gold surfaces can also be pre-functionalized with pyrene molecules, e.g., via Au-S chemistry [170] or diazonium salts [22], to represent the interface for aptamer immobilization. Since any aromatic structures with delocalized π electrons can interact with each other by π-π stacking and can be individually bound to gold and electrodes of other materials, the application of graphene, pyrene, and porphyrin offers a plethora of opportunities for sensor-surface functionalization.…”

“…Since the aptamer has a high affinity towards myoglobin, only the target molecule can cause dissociation and trigger fluorescence. [22,162,163,170,173,174].…”

“…Kong et al [22] modified a gold electrode with aryl diazonium salts by an electrochemical reductive method: the electrode was immersed in an aqueous solution of the salt and cyclic voltammetry was performed with a scan rate of 100 mV/s for three cycles between +1.0 and −1.0 V. This way, a surface-to-carbon bond is formed via the one-electron reductive formation of an aryl [22,162,163,170,173,174].…”

“…As an alternative to the interaction with carbon-based surfaces, gold electrodes can be pre-functionalized with covalently bound pyrene, which represents the interface for aptamer immobilization via π-π stacking. For this purpose, Lydon et al [170,175] synthesized thioacetate functionalized pyrene (S-(pyren-1-ylmethyl) ethanethioate) that can be covalently bound to gold via Au-S chemistry. The product can be isolated by nucleophilic substitution of 1-bromomethylpyrene with potassium thioacetate and has to be deprotected prior to its attachment onto gold by a strong base, e.g., NH 4 OH.…”