Fig. 5. Detection of synthetic S. aureus DNA by the proposed THz metamaterial biosensor. (A) Evaluation of the sensitivity of synthetic S. aureus DNA detection, based on metamaterial frequency shifts (Δf) resulting from the variation of DNA concentrations ranging from 1 fM to 100 pM. The inset shows the linear relationship between Δf and the logarithm of S. aureus DNA concentration. (B) Evaluation of the specificity of synthetic S. aureus DNA detection. A sequence that was not complementary to the PLP (shown in Table 1) served as the negative control (NTC). Error bars indicate the standard deviation (n = 3 in all cases).