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

Ekaterina Koposova, Alexandre Kisner, Galina Shumilova, Yury Ermolenko, Andreas Offenhäusser, and Yulia Mourzina

Appeared in: Journal of Physical Chemistry C 117 (2013) 13944–13951 

DOI: 10.1021/jp401764p  

Oleylamine-Stabilized Gold Nanostructures Assembly of cyt c on electrodes and transmission electron micrographs of Au NPs and Au NWs. Scale bars are 5 nm (Au NP) and 100 nm (Au NW).



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

CVs of cyt c CVs of cyt c on electrodes: line (a) and inset show CVs of a planar thin film Au-SAM-cyt c electrode and Au-SAM electrode (dashed line), Au-NPs-OP_SAM-cyt c (b), Au-NWs-OP-SAM-cyt c (c). Other conditions: scan rate 50 mV s?1, 4.4 mM phosphate buffer, pH 7.0.