Specific recognition of L-threonine by a terahertz metasurfaces biosensor based on fingerprint peaks

Arbitrarily designed resonant-based metasurfaces are particularly attractive and present a unique platform for biosensing applications owing to their ability to confine light to nanoscale regions and their spectral selectivity. In this study, we experimentally demonstrate a metasurface sensor based on terahertz fingerprint spectroscopy that enables the specific recognition of trace samples. The results of simulations and experiments show that this metasurface sensor detects glycine, L-arginine, and L-threonine, respectively, with different resonance coupling. The frequency shift of the resonance peak of the metasurface sensor was the largest when the resonance peak matched the fingerprint peak of the sample, with a maximum of 123 GHz for detecting L-threonine. Therefore, combining the frequency shift of the resonance peaks with the fingerprint spectrum of the sample can achieve specific recognition of the sample. This study provides new ideas for specific recognition of samples using metasurface sensors in biomedicine, food safety, and other fields.