Ultraprecise Detection of Low Molecular Weight Antibodies Using Mid-IR Toroidal Plasmonic Meta-Atoms

Plasmonic metamaterials can be used to enhance mid-infrared sensors and detectors for immunosensing applications. The major challenge is to integrate these technologies in low-cost, compact, and promising platforms. In this study, as an emerging approach, we utilized toroidal resonant plasmonic metasurfaces to develop an ultrasensitive label-free analytical platform for the detection of specific antibiotics in the mid-IR regime. Taking advantage of unique sensitivity of robustly squeezed electromagnetic fields in toroidal meta-atoms, we validated that our proposed technique based on toroidal metastructures can provide sensing of biological targets with the weight of ~0.6 KDa at attomolar concentrations. We believe that this understanding extends the capabilities of plasmonic metamaterials analyze the presence of specific biological targets with high precision.