Team:Freiburg/Diagnostics

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Diagnostics today

The detection of antibodies in a blood sample is a versatile and widely applied method of today's diagnostics 1) 2). Common methods include ELISA-assays which either rely on the capture of disease antigens by immobilized antibodies (sandwich and competitive ELISA) or on the direct immobilization of these antigens beforehand3). Both methods require stable conditions for handling and storage of the plates as test reliability is crucially dependent on native-state proteins. Maintaining these conditions is already quite expensive under European standards, but becomes elaborate when working in tropical or arid regions.

Especially in those regions, where hospitals are mostly hard to reach and local medical treatment seldom relies on physicians, it is necessary to reliably distinguish between different illnesses as fast as possible. The treatment of potential epidemic pathogens requires an enormous logistic effort and differential diagnosis of a less potent pathogen may save thousands of dollars and prevent fear among people. Thus, it would be beneficial to have a large library of known antigens that is easy and cost-effective to store and to ship, but nonetheless functions as a reliable selective tool in diagnostics.

Our idea of how to tackle this problem is to use the unique properties of DNA as a robust information storage and combine it with cell-free expression inside a detection device. The antigens, produced on-demand directly before diagnosis, are not only less prone to denaturation, but are also enriched on the array in the device by a specific surface. Antibodies potentially present in the patient's blood are then observed by a new kind of detection method called iRIf.

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2) Kaushik, A. et al., 2015. Towards detection and diagnosis of Ebola virus disease at point-of-care. Biosensors & bioelectronics, 75, pp.254–272.
3) Schuurs, A.H. & van Weemen, B.K., 1980. Enzyme-immunoassay: a powerful analytical tool. Journal of immunoassay, 1(2), pp.229–49.