Novel graphene

Graphene-like foam sensors from Stirlingshire-based Integrated Graphene can detect lactate concentrations for medical and fitness applications, according to research at the University of Bath.

The company describes its patented substrate as “a three-dimensional carbon-based nano-material consisting of twisted multi-layers of atoms arranged in a honeycomb structure”.

To form a lactate-detecting electrode, boronic acid was absorbed into the foam, and then coated with ‘poly-NHG’ (poly-nordihydroguaiaretic acid) – boronic acids is the active ingredient here as it forms chemical complexes with lactic acid.

In Bath’s proof-of-concept, used a 4mm diameter disc of the foam around 40µm thick, plus a counter electrode and a Ag/AgCl reference electrode.

Impedance spectroscopy (measuring impedance and phase against frequency) proved to be the most sensitive and revealing way to use the electrode, but voltammetry (voltage against current) and chronoamperometry (current against time) were also evaluated.

According to a paper describing the research: “Overall, this technique could be of great potential for use in clinical in vivo – blood or interstitial fluid – or ex vivo – sweat – lactate determination. .

‘Polymer indicator displacement assay (PIDA) with boronic acid receptors on graphene foam electrodes for self-optimised impedimetric lactic acid determination‘ is published in Sensors and Actuators B: Chemical. Available in full without payment, this includes details of the foam sensor, but it mostly an electro-chemistry and bio-chemistry paper.

Integrated Graphene was established in 2014, filing first UK patent in 2015. It is based in Stirling, Scotland.