Application of stilbene-(4,4′-diisothiocyanate)-2,2′- disulfonic acid as a bifunctional reagent for the organization of organic materials and proteins onto electrode surfaces

Trans-stilbene-(4,4′-diisothiocyanate)-2,2′-disulfonic acid (DIDS) acts as a bifunctional reagent for the organization of redox functionalized monolayers. Treatment of gold electrodes by cystamine generates the respective thiol-monolayer-modified gold electrode with a surface density corresponding to 5.4 × 10^-11 Mol cm^-2. Treatment of the cystamine-modified gold electrode with DIDS generates an active monolayer that can be further coupled to redox functionalities such as the amino quinone. The resulting quinone-monolayer-modified electrode displays electrochemical activity. Similarly, the cystamine + DIDS-monolayer-modified electrode reacts with amino functionalities of redox proteins, i.e. glutathione reductase. The resulting enzyme monolayer-gold electrode assembly is wired towards electron-transfer communication by covalent attachment of N-methyl-N′-(6-hexanoic acid)-4,4′-bipyridinium iodide as the electron relay component.