%0 Journal Article
%T Nanoporous Gold Electrodes and Their Applications in Analytical Chemistry
%A Maryanne M. Collinson
%J ISRN Analytical Chemistry
%D 2013
%R 10.1155/2013/692484
%X Nanoporous gold prepared by dealloying Au:Ag alloys has recently become an attractive material in the field of analytical chemistry. This conductive material has an open, 3D porous framework consisting of nanosized pores and ligaments with surface areas that are 10s to 100s of times larger than planar gold of an equivalent geometric area. The high surface area coupled with an open pore network makes nanoporous gold an ideal support for the development of chemical sensors. Important attributes include conductivity, high surface area, ease of preparation and modification, tunable pore size, and a bicontinuous open pore network. In this paper, the fabrication, characterization, and applications of nanoporous gold in chemical sensing are reviewed specifically as they relate to the development of immunosensors, enzyme-based biosensors, DNA sensors, Raman sensors, and small molecule sensors. 1. Introduction High surface area nanostructured electrodes have received considerable attention in recent years [1¨C18]. These materials are conductive, have surface areas that are typically 2¨C1000 times larger than a planar electrode of similar size, and consist of either oriented, well-defined or random pore morphology. Such high surface areas are important to a number of applications, particularly those in the field of chemical sensing when the goal is to improve sensitivity and lower detection limits. In electroanalytical chemistry, for example, the increased surface area can lead to a greater amount of an immobilized reagent on the surface. This can potentially lead to larger currents, even for diffusing species, because Faradaic current typically scales linearly with electrode area; a significantly larger electrode area can potentially yield better S/N ratios, enhanced sensitivity, and lower detection limits. High surface area noble metal electrodes have been fabricated using a number of different approaches including hard templating of latex spheres or SiO2 spheres [7, 8, 19, 20], chemical dealloying [9, 21], electrochemical dealloying [22, 23], H2 bubble formation [24], electrodeposition in the pores of nanopore membranes [1, 2] as well as from ensembles of gold nanoparticles [5, 6], gold microparticles [25, 26], and electrospun gold nanofibers [3, 4]. Each approach has its unique advantages and disadvantages. Figure 1 shows simple examples of different types of high surface area, nanostructured electrodes. Figure 1: Some examples of high surface area nanostructured gold electrodes. The focus of this paper is on nanoporous gold electrodes, particularly those
%U http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/692484/