A key challenge for sensor miniaturization is to create electrodes with smaller footprints, while maintaining or increasing sensitivity. In this work, the electroactive surface of gold electrodes was enhanced 30‐fold by wrinkling followed by chronoamperometric (CA) pulsing. Electron microscopy showed increased surface roughness in response to an increased number of CA pulses. The nanoroughened electrodes also showed excellent fouling resistance when submerged in solutions containing bovine serum albumin. The nanoroughened electrodes were used for electrochemical detection of Cu2+ in tap water and of glucose in human blood plasma. In the latter case, the nanoroughened electrodes allowed highly sensitive enzyme‐free sensing of glucose, with responses comparable to those of two commercial enzyme‐based sensors. We anticipate that this methodology to fabricate nanostructured electrodes can accelerate the development of simple, cost‐effective, and high sensitivity electrochemical platforms.

The ability to provide high sensitivity with small footprints makes miniaturized electrodes key components of biosensing, wearable electronics and lab-ona-chip devices. Recently, thin film deposition onto polystyrene films, followed by thermal shrinking has been used to produce microstructured electrodes (MSEs) with high electroactive surface area (ESA). Nevertheless, the high cost associated with film deposition through evaporation used in microfabrication and the variability in performance of screen-printed electrodes (SPEs) remain key barriers that limit their widespread deployment. Here, a simple and inexpensive method is developed for the solution-based patterning of high-quality metallic films on polystyrene substrates for MSE fabrication. The ESA of electrodes produced through this method is 2 × and 12 × larger than that of microstructured and planar electrodes produced through sputtering, respectively, and their cost is only 20% of sputtered ones. This methodology allows the fabrication of on-chip microstructured electrochemical cells (SMECs) with excellent analytical performance (3% RSD inter-day reproducibility and 0.3% RSD repeatability), superior to that of commercially available SPEs. In addition, the ESA of SMECs is significantly higher than that of SPEs, and they show excellent response toward dopamine detection. We anticipate that this solution-based fabrication approach will expedite the development of miniaturized sensing platforms for point-ofcare applications.

One of the main challenges for electrochemical sensor miniaturization is the fabrication of electrodes with a smaller footprint, while maintaining, or even increasing, their sensitivity for the targeted application. Our research group has previously demonstrated the enhancement of the electroactive surface area of gold electrodes up to 6-fold, relative to planar gold electrodes with the same footprint, through the generation of a wrinkled thin film surface via thermal shrinking. In this work, the electroactive surface area of wrinkled gold electrodes was further enhanced up to 5-fold (30-fold over flat electrodes) using a chronoamperometric pulsing technique. Scanning electron microscopy images showed progressive increase of surface roughness in response to an increasing number of applied pulses. The resulting nanoroughened electrodes present several advantages in addition to the enhanced electroactive surface area. These electrodes offer superior fouling resistance compared to that of wrinkled and flat electrodes when submerged in a solution containing bovine serum albumin at high concentrations. Cyclic voltammetry data also revealed greater sensitivity of nanoroughened electrodes toward anodic copper stripping, where the limit of quantification of copper by the nano-roughened electrodes was 0.3 ppm. Nano-roughened electrodes also allowed the highly sensitive enzyme-free detection of glucose through chronoamperometry, with a limit of detection of 0.5 mM, whereas planar electrodes did not demonstrate any ability to oxidize glucose. We foresee that this methodology to fabricate nanostructured electrodes will accelerate the development of simple, cost-effective and high sensitivity electrochemical platforms.

A key challenge for sensor miniaturization is to create electrodes with smaller footprints, while maintaining or increasing sensitivity. In this work, the electroactive surface of gold electrodes was enhanced 30‐fold by wrinkling followed by chronoamperometric (CA) pulsing. Electron microscopy showed increased surface roughness in response to an increased number of CA pulses. The nanoroughened electrodes also showed excellent fouling resistance when submerged in solutions containing bovine serum albumin. The nanoroughened electrodes were used for electrochemical detection of Cu2+ in tap water and of glucose in human blood plasma. In the latter case, the nanoroughened electrodes allowed highly sensitive enzyme‐free sensing of glucose, with responses comparable to those of two commercial enzyme‐based sensors. We anticipate that this methodology to fabricate nanostructured electrodes can accelerate the development of simple, cost‐effective, and high sensitivity electrochemical platforms.

One of the main challenges for electrochemical sensor miniaturization is the fabrication of electrodes with a smaller footprint, while maintaining, or even increasing, their sensitivity for the targeted application. Our research group has previously demonstrated the enhancement of the electroactive surface area of gold electrodes up to 6-fold, relative to planar gold electrodes with the same footprint, through the generation of a wrinkled thin film surface via thermal shrinking. In this work, the electroactive surface area of wrinkled gold electrodes was further enhanced up to 5-fold (30-fold over flat electrodes) using a chronoamperometric pulsing technique. Scanning electron microscopy images showed progressive increase of surface roughness in response to an increasing number of applied pulses. The resulting nanoroughened electrodes present several advantages in addition to the enhanced electroactive surface area. These electrodes offer superior fouling resistance compared to that of wrinkled and flat electrodes when submerged in a solution containing bovine serum albumin at high concentrations. Cyclic voltammetry data also revealed greater sensitivity of nanoroughened electrodes toward anodic copper stripping, where the limit of quantification of copper by the nano-roughened electrodes was 0.3 ppm. Nano-roughened electrodes also allowed the highly sensitive enzyme-free detection of glucose through chronoamperometry, with a limit of detection of 0.5 mM, whereas planar electrodes did not demonstrate any ability to oxidize glucose. We foresee that this methodology to fabricate nanostructured electrodes will accelerate the development of simple, cost-effective and high sensitivity electrochemical platforms.