(Invited) Potential Applications of Nano-Electrochemistry in Point-of-Care Sensing Devices

Abstract

Using low noise electronics and micro-electrodes we can now electrochemically detect and count single, nanometer-scale objects in solution.1,2 This talk will cover recent discoveries in the field of single entity electrochemistry showing that electro-inactive species, including proteins, DNA, and even cells, can be detected individually using unmodified electrodes.3–5 Despite these advances, however, limitations persist. The location upon which the individual analyte adsorbs onto the electrode surface influences the magnitude of the electrochemical signal it produces.6,7 Consequently, the electronic output does not reflect the true physical properties of the biological entity, thus inhibiting the analytical resolution desired for applications.In response, we have shown that coupling the electrochemical reaction to a homogeneous, rate-limiting chemical reaction ameliorates this problem, improving the precision of single-entity electrochemical blocking measurements. Using both finite element simulations and experimental statistical analysis we provide guidance for the sizing of redox-inactive materials with high analytical precision under a range of conditions, including variations in electrode size and analyte concentration. The presented nanoscale electrocatalytic approach could offer a novel means of achieving cost-effective, rapid, real-time detection of nanometer-scale “insulators” in complex media, an advance that could be of significant relevance to point-of-care medical diagnostics.