Attomolar Detection of Low-Molecular Weight Antibiotics Using Midinfrared-Resonant Toroidal Plasmonic Metachip Technology

The rise of toroidal plasmonic metamaterial sensors has revitalized the precision of optical immunobiosensors. While detection at ultralow concentrations with conventional midinfrared plasmonic biosensors is challenging, toroidal metamaterial technology has enabled the development of ultrasensitive, label-free recognition and detection of low-weight biological objects at femto- and attomolar concentrations. The proposed metasensor is able to detect about 600 Kantrex molecules in 200 mm${}^{3}$ of solution. This remarkable performance stems from the exquisite sensitivity of robustly squeezed electromagnetic fields in the toroidal plasmonic metastructures.