Graphene oxide enables rapid infection detection

Researchers at the Fraunhofer Institute for Reliability and Microintegration IZM have joined forces with partners in industry and health care to develop a graphene oxide-based sensor platform to detect acute infections within minutes.

The COVID-19 pandemic has underscored the importance of detecting infections quickly and accurately to prevent further spread. Blood tests can provide certainty, but laboratories only carry these out when prescribed by a GP. By the time the results arrive from the lab, doctors have often prescribed an antibiotic that may well be unnecessary.

Looking to overcome these challenges, researchers at Fraunhofer IZM have been working on the Graph-POC project to develop a graphene oxide-based sensor platform. Electrically conductive and biocompatible, graphene oxide is also said to be a very reliable means of detection. To date it has only been used in microelectronics in its original form, a 2D monolayer. The researchers are applying it in a 3D structure in form of flakes, which increases the measuring surface and the accuracy of measurements.

A single drop of blood or saliva is all it takes to perform an accurate analysis: just a few minutes after the drop is applied to the sensor’s surface, electrical signals convey the test result to the doctor’s office. This rapid test provides certainty within just 15 minutes to replace the protracted blood work in the lab, taking the guesswork out of diagnosis so the physician can prescribe the appropriate treatment or suitable antibiotics.

The test may also be set up to detect antibodies that are present after a patient has recovered from an infection. The researchers are now focusing on this application to detect earlier infections of COVID-19, which can help with efforts to trace how the infection has spread. The human body forms molecules or proteins called biomarkers in response to an infection. Capture molecules are placed on the surface of the graphene-based sensor to detect these biomarkers. Differential measurements of biomarkers’ concentration determine if an infection is present.

The graphene oxide flakes’ 3D array and heightened sensitivity open the door to a variety of applications. For example, it could detect harmful gases such as carbon monoxide or acetone even at room temperature. As it stands, these gases have to first be heated to trigger a surface reaction that today’s sensors can detect. The graphene oxide sensor reacts at lower temperatures when metal oxides bond with its sensitive surface.

Although the original project to detect infections is slated to run until mid-2021, the researchers do not expect to be able to verify the sensor for COVID-19 for another year yet. They are also looking to scale the production process up for mass manufacturing, by applying the graphene oxide coating at the wafer level so that hundreds of chips can be processed at once.

Manuel Bäuscher, Sub-Project Manager at Graph-POC, concluded that there are great prospects ahead for the graphene oxide sensors. “We can pivot from the current medical field to also develop in the direction of the point of need; that is, towards environmental technology and the detection of environmental impacts. But of course the corona application is our first priority,” he said.

Image ©Fraunhofer IZM.

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