Nanoporous Gold Electrodes with Tuneable Pore Sizes for Bioelectrochemical Applications. Issue 10 (6th October 2016)

• Record Type: Journal Article
• Authors: Siepenkoetter, Till; Salaj‐Kosla, Urszula; Xiao, Xinxin; Belochapkine, Serguei; Magner, Edmond
• Is Part Of: Electroanalysis. Volume 28:Issue 10(2016)
• Page Start: 2415
• Page End: 2423
• Publication Date: 2016-10-06
• Subjects: Electrochemistry -- Material Science -- Mesoporous Material -- Nanoelectrodes -- Bioelectrochemistry; Electrochemical analysis -- Periodicals; Chemistry, Analytical -- Periodicals; Electrochemistry -- Periodicals; 543.4
• DOI: 10.1002/elan.201600249
• Languages: English
• ISSNs: 1040-0397

Abstract

Abstract: Nanoporous gold (NPG) fabricated by sputtering is a material of versatile morphology with pores whose size can be tailored to accommodate enzymes. The process of pore formation and the size of the pores in NPG are influenced by the composition of Au and Ag in the alloy used to prepare the electrodes together with the temperature and time period of the dealloying process. On increasing the time from 1 to 60 min and the temperature from 0.5 °C to 60.5 °C in concentrated HNO3, significant increases in the average pore diameters from 4.4 to 78 nm were observed with simultaneous decreases in the roughness factor (Rf ). The pores of NPG were fully addressable regardless of the diameter, with Rf increasing linearly up to an alloy thickness of 500 nm. The influence of the pore size on the bioelectrochemical response of redox proteins was evaluated using cytochrome c as a model system. The highest current densities of ca . 30 µA cm −2 were observed at cytochrome c modified NPG electrodes with an average pore size of ca. 10 nm. The pores in NPG were also tuned for the mediatorless immobilization of Myrothecium verrucaria bilirubin oxidase. High current densities of ca . 65 µA cm −2 were observed at Mv BOD modified NPG electrodes prepared by dealloying at 0.5 °C for 5 min with an average pore size of 8 nm, which is too small to accommodate the enzyme into the pores, indicating that the response was from enzyme adsorbed on the electrode surface. Abstract :