Graphene foam and boronic acid combine for accurate glucose sensor

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Researchers have developed a sensing technique based on graphene foam for the detection of glucose levels in the blood, an advance that could help people living with diabetes to better manage their condition.  

graphene foam
The enzyme-free sensor is more robust and not temperature sensitive so could be particularly useful in hot countries or where refrigeration is limited. (Credit: Integrated Graphene)

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. This means that people with diabetes must measure their blood sugar levels several times a day as part of condition management.  

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 University and Integrated Graphene uses a chemical sensor, which is said to be more robust and is not affected by high temperatures or changes in pH. It also 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.

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According to Bath, the new sensor is based on 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, so the concentration of glucose in the sample can be accurately measured.

In a statement, Simon Wikeley, who is working on the sensor as part of his chemistry PhD at Bath University, 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.

“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.”

The research was supported by the EPSRC and Integrated Graphene and is published in Analyst.