Novel chemical glucose sensing method based on boronic acids and
graphene foam

Date:
February 2, 2022
Source:
University of Bath
Summary:
Researchers have developed a new glucose sensor that is cheaper
and more robust than current systems.



FULL STORY ========================================================================== Researchers at the University of Bath working in collaboration with
industrial partner, Integrated Graphene, have developed a new sensing
technique based on graphene foam for the detection of glucose levels in
the blood. Since it is a chemical sensor instead of being enzyme-based,
the new technology is robust, has a long shelf-life and can be tuned to
detect lower glucose concentrations than current systems.


========================================================================== Diabetes affects around 4.9 million people in the UK and is a chronic
condition where the patient cannot naturally regulate their blood
sugar levels.

Therefore, patient must measure their blood sugar levels several times
a day as part of managing their condition.

Many current biosensors use enzymes that bind glucose and produce an
electric current proportional to the concentration of glucose in the
blood sample.

The new technique developed by scientists at Bath and Integrated Graphene
uses a chemical sensor, which is more robust and is not affected by
high temperatures or changes in pH. Furthermore, it has the potential to accurately detect a wider range of glucose concentrations above and below current biosensor ranges, which may be useful in neonatal glucose sensing.

The new sensor is based on the chemical boronic acid, which is attached to
a graphene foam surface. An electroactive polymer layer is added on top
and binds to the boronic acid. When glucose is present, it competitively
binds to the boronic acid, displacing the polymer.

The sensor produces an electric current proportional to how much polymer
is displaced, meaning that the concentration of glucose in the sample
can be accurately measured.



==========================================================================
The researchers anticipate the sensor will expand the scope of boronic
acid - - based glucose sensing, citing the recent Eversense CGM from
Sensonics as an example. However, unlike Eversense, their sensor is based
upon electrochemical methods rather than fluorescence, thereby enabling
new boronic acid -- based glucose sensing approaches.

Simon Wikeley, who is working on the sensor as part of his Chemistry
PhD at the University of Bath, said: "Many current glucose sensing
methods rely on biological components such as enzymes, meaning they can
be sensitive to temperature and pH changes, which may affect accuracy
and reliability'.

"We hope that in the future we might be able to apply our glucose
detection method to exciting new technologies, such as wearable or
implantable glucose monitoring systems, similar to that used in the
Eversense sensor.

"Our system is chemical-based and therefore is robust and reliable. The graphene foam electrode has a high surface area to interact with the
blood sample, while the polymer can act as a molecular sieve, filtering
out larger molecules in the blood that could interfere with the glucose sensing.

"This sensor has proven to be reusable, which is the first step towards realising a continuous monitoring system.



========================================================================== "Interestingly, this same sensing technique may also be applied to a wide
range of other targets, such as lactic acid. This is due to the versatile nature of the boronic acid receptor and gives us a general strategy
for a variety of sensing applications." Professor Tony James, who is a
Royal Society Wolfson Research Merit Award holder at the University of
Bath's Department of Chemistry and helped supervise the project, said:
"We're excited by our results as this is the first time this approach
has been used for glucose sensing.

"We are still in the early stages of optimising sensitivity and
reproducibility but hope this new technology could be used in a wide
range of applications, from medical sensing to food production.

"It could also be adapted to sense other molecules or for use in
continuous flow systems." Dr Marco Caffio, Co-Founder and CSO of
Integrated Graphene, said: "When we started Integrated Graphene, one of
the things that initially excited us was the plethora of sensing solutions
we would be able to develop and ameliorate on the incumbent method by
utilising the extraordinary sensing capabilities of our 3D graphene foam.

"Now, with this project alongside the University of Bath, we are
beginning to see some of that potential being realised to create a
more cost-effective and therefore accessible platform by using a new, enzyme-free glucose monitoring sensor solution.

"Now that we have proved this technique, it opens up the opportunity
to take the underlying applied methodology to a vast range of similar point-of-care diagnostics that could profit from associated benefits
such as reduced cost and enhanced shelf-life.

"Furthermore, the identified opportunities for means of enhancing the analytical methodology provides sufficient desirability to enhance
the platform even more." The research was supported by the EPSRC and Integrated Graphene and is published in the scientific journal Analyst.

========================================================================== Story Source: Materials provided by University_of_Bath. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Simon M. Wikeley, Jakub Przybylowski, Pablo Lozano-Sanchez,
Marco Caffio,
Tony D. James, Steven D. Bull, Philip J. Fletcher, Frank
Marken. Polymer indicator displacement assay: electrochemical
glucose monitoring based on boronic acid receptors and graphene
foam competitively binding with poly- nordihydroguaiaretic acid. The
Analyst, 2022; DOI: 10.1039/D1AN01991K ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220202134700.htm

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