Gii-Sens Electrodes in Electrochemical Sensing
Author: Simon Wikeley
New advances in electrochemical sensors have proven their potential beyond their traditional use in glucose monitoring. My research with the University of Bath has shown graphene-based Gii™ electrodes have the specificity and scaleability to improve point-of-care testing for a wider range of human diagnostics.
These findings were the subject of a talk given at the ACS conference in San Francisco in August entitled ‘Polymer Indicator Displacement Assays in Electrochemical Sensing’.
In looking at the sensing capabilities of Gii™ electrodes, an innovative polymer indicator displacement assay (PIDA) technique was developed and initially applied to glucose sensing (2) and now for lactic acid determination.
In this sensor design, boronic acids were used as the recognition element for lactic acid. This took inspiration from previous fluorescence-based techniques carried out in the group of Professor Tony James, in this case applying boronic acids to electrochemical detection, potentially yielding more robust sensors compared to traditional enzymatic techniques.
During voltammetric sensing, an oxidising potential was applied to the solid-state T1 and NHG functionalised electrode sensor, resulting in significant changes in electrochemical decoupling of this complex. Lactic acid binds to the boronic acid which significantly alters voltammetric peak signals, allowing for accurate calibration graphs.
Figure 1: Stepwise illustration of the experimental protocol to generate the sensor film with boronic acid T1 and redox polymer before application in electroanalytical detection of lactate (1).
The research on electrochemical sensors using synthetic receptors attached to Gii™ electrodes shows strong promise for the future of sensors. The PIDA technique is an innovative approach to electrochemical chemo-sensing, enabling accurate and selective detection. The integration of Gii electrodes, with their exceptional properties such as conductivity and high surface area for chemical functionalisation, is vital to the success of these sensors.
As a novel 3D graphene, Gii™'s properties make it an excellent platform for integrating boronic acid receptors and redox-active molecules like NHG in the PIDA technique. NHG spontaneously forms a polymer on the Gii-Sens™ electrodes, making the sensor solid-state and eliminating the need for solution-based redox mediators. Gii-Sens™’ high surface area increases sensitivity and reproducibility by more than 10 times compared to incumbent sensing materials and consistently outperforms noble metal alternatives.
The findings offer novel insights into electrochemical chemo-sensing, paving the way for the development of more efficient and durable sensors.
Electrochemical biosensors have been an active part of glucose monitoring for many years, allowing virtually immediate results, point-of-care, to millions of diabetic patients. With the current strain on health services around the world, accurate sensing methods can ease pressures through the removal of result waiting times and not requiring lab conditions.
Accurate glucose monitoring will significantly improve patient outcomes, but the potential benefits of Gii™-based electrodes in the field of human diagnostics go well beyond this specific use. The researchers' work brings us closer to transforming the way we detect and monitor critical analytes, enabling us to improve the way to test for and manage a wider range of life-limiting health conditions.