APTERA II - Electromagnetic THz- and mm-wave Sensors for African Trypanosomes using RNA Aptamer-Derivatized Surface Layers

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The goal of our collaborative research effort is the development of an electromagnetic (EM) sensor device for the detection of African trypanosomes. Trypanosomes are single cell organisms that cause African trypanosomiasis, a parasitic disease that is also known as African sleeping sickness. If left untreated, sleeping sickness is fatal and thus, the early detection of parasite cells in the blood and/or the cerebrospinal fluid of infected patients is for health workers and clinicians crucial. As initially proposed, the EM-sensors operate in the mm- and THz-frequency region and in order to facilitate the binding of parasites to the sensory surface they are covalently functionalized with so-called aptamer molecules. Aptamers are synthetic, biomolecular affinity reagents, which in this case have been designed to specifically adhere to the surface of trypanosome cells. In the 1st funding period we were able to demonstrate the general applicability of our EM-aptasensor approach and for the 2nd funding period we now propose to use the generated data and knowledge to make the next steps towards a first prototype diagnostic device. Specifically, we intend to increase the sensitivity of the sensory surface to lower the detection limit to be able to detect even very low numbers of parasites. Furthermore, we suggest to extend our detection principle to "wet conditions" to be able to handle and measure "true" biological samples such as trypanosome-infected blood or serum specimen. The electromagnetic properties of these “wet samples” will be thoroughly characterised. We consider spoof plasmonic structures and a special system of two coupled resonators to achieve increased sensitivity and the ability to measure under wet conditions with high losses due to the water. We also propose to expand our investigation into more sophisticated aptamer-derivatized surfaces such as multifunctional and multilayered aptamer surfaces and we propose to generate aptamer/nanobody hybrid surfaces to potentially lower the detection limit even further. The proposal includes all necessary steps to demonstrate “proof-of-principle” of the EM-aptasensor approach and is intended to provide the groundwork for the design of a prototype-device for a fast, robust and low cost detection of African sleeping sickness. The construction of a first integrated chip that contains next to the aptasensor all the necessary electronic circuitry for signal generation and detection is planned as part of a cooperative effort together with Prof. Kissinger.