Journal Article

Accelerated Electron Transfer in Nanostructured Electrodes Improves the Sensitivity of Electrochemical Biosensors

Eisenstein, Michael, Soh, H. Tom, Maganzini, Nicolo, Kesler, Vladimir, Fu, Kaiyu, Wilson, Brandon D., Murmann, Boris, Seo, Ji‐Won

2021

Overview

Electrochemical biosensors hold the exciting potential to integrate molecular detection with signal processing and wireless communication in a miniaturized, low‐cost system. However, as electrochemical biosensors are miniaturized to the micrometer scale, their signal‐to‐noise ratio degrades and reduces their utility for molecular diagnostics. Studies have reported that nanostructured electrodes can improve electrochemical biosensor signals, but since the underlying mechanism remains poorly understood, it remains difficult to fully exploit this phenomenon to improve biosensor performance. In this work, electrochemical aptamer biosensors on nanoporous electrode are optimized to achieve improved sensitivity by tuning pore size, probe density, and electrochemical measurement parameters. Further, a novel mechanism in which electron transfer is physically accelerated within nanostructured electrodes due to reduced charge screening, resulting in enhanced sensitivity is proposed and experimentally validated. In concert with the increased surface areas achieved with this platform, this newly identified effect can yield an up to 24‐fold increase in signal level and nearly fourfold lower limit of detection relative to planar electrodes with the same footprint. Importantly, this strategy can be generalized to virtually any electrochemical aptamer sensor, enabling sensitive detection in applications where miniaturization is a necessity, and should likewise prove broadly applicable for improving electrochemical biosensor performance in general. In this work, nanostructured electrodes with tunable porosity for electrochemical biosensing that offer increased signal level and lower limit of detection than conventional planar electrodes are reported. Importantly, a novel mechanism in which electron transfer is physically accelerated within nanostructured electrodes due to reduced charge screening, resulting in enhanced sensitivity is proposed and experimentally validated.

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc,Wiley
• Subject: aptamer / Biosensing Techniques - instrumentation / Biosensing Techniques - methods / Biosensors / electrochemical sensors / Electrochemical Techniques - instrumentation / Electrochemical Techniques - methods / Electrodes / electron transfer / Electron Transport / Electrons / Equipment Design / Gold / Metal Nanoparticles - chemistry / Miniaturization - methods / nanopores / Noise / Pore size / Scanning electron microscopy / Sensors / Standard deviation