Terahertz phase shift sensing and identification of a chiral amino acid based on a protein-modified metasurface through the isoelectric point and peptide bonding

g /ml, much higher than traditional sensing parameters. Due to the specific electrostatic adsorption by the functionalized metasurface to L-Arg, its detection sensitivity and precision are 22 times higher than the other amino acids. Furthermore, by comparing nonfunctionalized and functionalized metasurfaces, the D- and L-chiral enantiomers of Arg were distinguished due to their different binding abilities to the functionalized metasurface. Therefore, this EIT metasurface sensor and its specific binding method improve both detection precision and specificity in THz sensing for amino acids, and it will promote the development of THz highly sensitive detection of chiral enantiomers.