Researchers are working on a technology platform for rapid tests for the mobile detection of viruses, viral proteins or antibodies. This should not only detect SARS-CoV-2. An altered electrical conductivity is measured.
New Technology Platform for Rapid Testing
In the fight against the Corona pandemic, governments are focusing on testing options in addition to vaccination. In the process, scientists agree that the diagnostic toolbox needs to be constantly expanded. Not only to counter SARS-Cov-2. Chemists at Friedrich Schiller University Jena, IMMS Institut für Mikroelektronik- und Mechatronik-Systeme gemeinnützige GmbH (IMMS) and fzmb, Research Center for Medical Technology and Biotechnology are therefore jointly developing a new technology platform for rapid tests.
On March 5, the project “ViroGraph – Multiplex Detection System for the Detection of Viruses Based on Graphene Field Effect Transistors”, which is funded by the German Federal Ministry of Economics and Technology and is scheduled to run for two and a half years, kicked off with a virtual kick-off meeting that was also attended by the members of the accompanying committee from six companies and institutions.
Graphene Sensors for Mobile Detection
The goal of the electronic platform is to open up the graphene sensors already being researched at the University of Jena for new so-called point-of-care devices. In the future, such small and mobile devices should be as easy to use as Covid-19 rapid tests on site and detect viruses, viral proteins or antibodies with high sensitivity – comparable to PCR tests. With the new project, the partners aim to lay the foundation for many more precise, sensitive and specific applications in the field of on-site diagnostics beyond SARS-CoV-2.
In principle, certain proteins are applied to the test strips of the rapid tests currently in use as capture molecules, which – if present in the sample tested – react with virus components or with antibodies. This produces a colored stripe that indicates the result. In the new platform of the ViroGraph project, a novel electronic sensor made of graphene will take over the task of the test strip – covered by a carbon membrane only one nanometer thick, which fixes the capture molecules to the sensor surface.
If the analytes from a sample – such as antibodies or virus components – accumulate on the sensor surface, the electrical conductivity of the sensor changes. This parameter can be read electronically and provides the test result.
Sensitive Changes in Conductivity
“Field-effect transistors are already used, for example, to measure pH values, but until now they have not been sensitive and specific enough for applications in immunological diagnostics,” explains Prof. Dr. Andrey Turchanin of the University of Jena. “However, the combination of heterostructures made of graphene, which provides an appropriate conductivity, and the molecular carbon nanomembrane, which biochemically functionalizes the sensor surface, made it possible to overcome the weakness.
This is because the 2D material graphene, which consists of only one atomic layer, is characterized by a special electrical conductivity – sensitive changes in conductivity during the coupling of analytes, i.e. the molecules being sought, can be measured quickly and easily.”
Detecting different Virus Mutations
In order to be able to measure these tiny electrical currents of just a few nanoamperes at all, the IMMS project coordinators are developing suitable miniaturized measurement technology. “This is important in order to integrate the performance required for our application of very large measuring devices that can normally determine such parameters into a handy point-of-care device,” says Michael Meister of IMMS. “In addition, a particular challenge here is to measure several graphene sensors simultaneously in order to be able to realize multiparameter analytics.”
After all, this is where the particular strength of the electronic method should lie. “We want to lay the foundation for a multiplex detection system with which we can detect several analytes simultaneously,” explains Dominik Gary of fzmb, whose team is developing immunological and molecular biological detection systems for the new sensor. “Thus, the ViroGraph system would potentially even be suitable for gene typing and could therefore detect various mutations of viruses in a rapid manner.”