Ultra-Sensitive Sensing of Bacteria With Terahertz Spoof Surface Plasmon Polariton Resonators

Biosensors are key components for the early detection of diseases. As such, a higher sensitivity allows for an earlier detection or even detection before symptoms form, as most pathogens and biomarkers have extremely small concentrations. Here we present an ultra-sensitive biosensor based on the scattering of terahertz waves in a spoof surface plasmon polariton resonator on bacteria. While the strongly bound wave and the high-quality factor of the resonator allow a sensitivity in the order of single bacteria, a high selectivity – the other key feature of a good biosensor – is provided by a surface functionalization with aptamers.