Electrochemical Nano‐Roughening of Gold Microstructured Electrodes for Enhanced Sensing in Biofluids**

Abstract

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.

Tip-Enhanced Sub-Femtomolar Steroid Immunosensing via Micropyramidal Flexible Conducting Polymer Electrodes for At-Home Monitoring of Salivary Sex Hormones

“…Note that the larger electrode area could provide a higher current response (>2-fold) than the isolated microelectrodes alone (Figure S5), thus maintaining the high sensitivity even at very small electrode size. 47 For instance, when the area of a micropyramidal electrode was reduced by >30-fold to ∼ 3 mm 2 , it still allowed the detection of P4 over 0.1 fM to 1 nM with a comparable sensitivity (Figure S6). Similarly, microarchitected electrodes with dendritic metal micro/nanostructures 48,49 or 3D-printed metal micropillars 34 on a ∼4 mm 2 area also demonstrated the rapid detection of pM-to sub-pM-level proteins in saliva and blood samples, realizing an LoD of at least 1 order of magnitude lower than the flat electrodes as well.…”

“…This work utilized a nanoparticle-decorated nanoporous conducting polymer biosensing interface combined with the 3D microarchitected electrode, which affords a good trade-off among the detection limit, speed, and dynamic range, as well as straightforward preparation. Note that the larger electrode area could provide a higher current response (>2-fold) than the isolated microelectrodes alone (Figure S5), thus maintaining the high sensitivity even at very small electrode size . For instance, when the area of a micropyramidal electrode was reduced by >30-fold to ∼ 3 mm 2 , it still allowed the detection of P4 over 0.1 fM to 1 nM with a comparable sensitivity (Figure S6).…”

Nanophotonic immunoarray with electrochemically roughened surfaces for handheld detection of secreted PD-L1 to predict immuno-oncology efficacy

“…15,16 As SERS signals subsequently decreased beyond the optimized conditions, we hypothesized that the reduction in SERS signals was due to structural instability and subsequent collapse of the gold nanostructures at higher voltages and pulse number. 28…”

Shrinking Devices: Shape‐Memory Polymer Fabrication of Micro‐and Nanostructured Electrodes

“…Recently, our group used nanoroughening to increase the ESA of SMPEs, fabricated on PS sheets, 31-fold relative to that of planar electrodes of the same footprint. [46] Three-dimensional nanostructures were formed on the wrinkled electrode surfaces by applying repeated high-voltage pulses over short time ) SEM images of sputtered and electroless plated gold electrodes show an appreciable difference in surface roughness and grain. All images were taken at the same magnification.…”