Session: Advances in Electrochemistry:

One of the main challenges for portable sensor development is the fabrication of sensing electrodes with an ever-smaller footprint, while maintaining, or increasing, the sensitivity of current sensors. Our research group has shown that by wrinkling a thin gold film, through shrinking of a thermo-responsive substrate, it is possible to increase the electroactive surface area of a gold working electrode 6-7-fold relative to a planar gold electrode of the same footprint. In this presentation, we will describe an approach to increase the electroactive surface area of gold electrodes up to 30-fold through wrinkling followed by chronoamperometric pulsing. Scanning electron microscopy images showed that the nanoscale surface roughness of the wrinkled electrodes could be tuned through the number of applied pulses. The resulting nanoroughened electrodes present unique advantages, in addition to the enhanced electroactive surface area. First, these electrodes offer superior fouling resistance to protein adsorption when compared to flat or wrinkled electrodes, allowing the sensing of redox-active species in solutions containing BSA concentrations comparable to those in blood. Moreover, cyclic voltammetry revealed greater sensitivity of nanoroughened electrodes toward anodic copper stripping, with copper detection 1.4× higher than that achieved by wrinkled electrodes. Nanoroughened electrodes also showed enhanced enzyme-free detection of glucose, with a limit of detection of 0.5 mM, comparable to the limits of detection for commercial glucose sensors. In contrast, planar electrodes did not demonstrate any ability to oxidize glucose. We foresee that the simplicity of the fabrication method and the high electroactive surface area will make these electrodes excellent platforms for the further conjugation of DNA primers and other small bioactive molecules for high sensitivity biosensing.

Jose Moran-Mirabal

Appearances