Terahertz toroidal dipole metamaterial sensors for detection of aflatoxin B1

Abstract

Terahertz metamaterial biosensors have gained significant attention in the biological field due to their label-free, real-time and in-situ detection advantages. In this paper, a highly sensitive metamaterial sensor with semi-ring mirror symmetry based on toroidal dipole resonance was designed for a new metamaterial biosensor. It is shown that 337.5 GHz/RIU refractive index sensitivity can be achieved under the analyte of saturated thickness near 1.33 THz transmission dip. For biosensor samples where aflatoxin B1 was spotted on the metamaterial surface in our experiment, the dip amplitudes of transmission varying from 0.1904 to 0.203, 0.2093 were observed as aflatoxin B1 concentrations alter from 0 to 0.001 μg/mL, 0.01 μg/mL respectively. Furthermore, when aflatoxin B1 concentrations are 0.1 μg/mL, 1 μg/mL,10 μg/mL, 100 μg/mL, dip amplitudes of 0.2179, 0.226, 0.2384, 0.2527 and dip redshifts of 10.1 GHz, 20.1 GHz, 27.7 GHz, 37.6 GHz are separately provided. These results illustrate high-sensitivity and label-free detection of aflatoxin B1, enriching the applications of sensors in the terahertz domain.