Oleylamine-Stabilized Gold Nanostructures for Bioelectronic Assembly. Direct Electrochemistry of Cytochrome c

Abstract

Methods to prepare ultrathin gold nanowires and monodisperse nanoparticles based on the intrinsic property of gold(I) ions to form aurophilic interactions stabilized by oleylamine and long-chain alkylamine have been widely explored. Due to the low thermodynamic stability of the high aspect ratio nanostructures, their conjugation and assembly into functional nanosystems have not been explored so far. One of the reasons for this is that the surface of the nanostructures is insulated by stabilization compounds, which preserve the integrity of the nanostructures but at the same time form an insulating barrier in electronic and electrochemical systems in contact areas and for the charge transfer reactions. Conjugation of a metalloprotein cytochrome c (Cyt c) with oleylamine-stabilized gold ultrathin nanowires and nanoparticles into a bioelectrochemically active nanoarchitecture is presented here for the first time. Methods of preparing and assembling the ultrathin nanowires and nanoparticles on the thin-film gold electrodes are shown. Thermodynamic and kinetic parameters were obtained for the direct electron transfer reaction of cyt c on these surfaces. Nanowires are responsible for an approximately −20 mV shift in the redox potential of the ferri/ferro-cyt c couple relative to a thin-film gold electrode.

Behavior of metal ions in bioelectrochemical systems: A review

“…It was demonstrated that the reduction of the potentialdetermining ion, Au(I), on the nanostructure electrodes could be proceeded at potentials more negative than that for the planar metal electrode [117].…”

Modulation of the Silica Sol–Gel Composition for the Promotion of Direct Electron Transfer to Encapsulated Cytochrome c

“…Accordingly, several strategies for the immobilization of enzymes have been assayed: covalent binding 15,16 , physical adsorption [17][18][19][20][21] or encapsulation within polymeric matrices 22 .…”

Ultrathin Au nanowires supported on rGO/TiO2 as an efficient photoelectrocatalyst

“…25 The electrocatalytic alcohol oxidation using Au as the catalyst is sensitive to the structure of the gold surface. 29,30 In this study, we use ultrathin Au nanowires synthesized using wet chemical means 31, 32, 33 as a catalyst for alcohol oxidation reactions. 26 Thus, it would be interesting to investigate the use of Au nanowire as a potential candidate for electrocatalytic reactions.…”