Articles | Volume 7, issue 1
Special issue:
Regular research article
23 Feb 2018
Regular research article |  | 23 Feb 2018

Design and evaluation of split-ring resonators for aptamer-based biosensors

Tobias Reinecke, Johanna-Gabriela Walter, Tim Kobelt, André Ahrens, Thomas Scheper, and Stefan Zimmermann

Abstract. Split-ring resonators are electrical circuits, which enable highly sensitive readout of split capacity changes via a measurement of the shift in the resonance frequency. Thus, functionalization of the split allows the development of biosensors, where selective molecular binding causes a change in permittivity and therefore a change in split capacity. In this work, we present a novel approach using transmission line theory to describe the dependency between permittivity of the sample and resonance frequency. This theory allows the identification of all relevant parameters of a split-ring resonator and thus a target-oriented optimization process. Hereby all setup optimizations are verified with measurements. Subsequently, the split of a resonator is functionalized with aptamers and the sensor response is investigated. This preliminary experiment shows that introducing the target protein results in a shift in the resonance frequency caused by a permittivity change due to aptamer-mediated protein binding, which allows selective detection of the target protein.

Short summary
A systematic investigation of a split-ring resonator for application as a biosensor is presented. The parameters responsible for the sensitivity of the setup were determined using a new approach to determine the resonance frequency depending on the relative permittivity of the sample. Based on these parameters, the resonator structure was optimized. Subsequently, a split-ring resonator was functionalized with aptamers and a selective detection of CRP could be shown.
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