Fig. 4. Biosensing demonstration with SARS-CoV-2 gene fragment targets.

a Measured spectra from individual resonators indicate significant wavelength shifts of ~ 0.2 nm with complementary DNA binding and minimal signal changes when introduced to non-complementary sequences. b Concentration-dependent binding responses for both nCoV.E and HKU.ORF1 targets incubated on metasurface devices functionalized with only nCoV.E complementary probes. Error bars indicate standard deviations of measurements from N = 20 measurements from distinct resonators for each target and concentration condition. The limit of detection is estimated based on the mean + 3 standard deviations of the blank measurements. Dashed lines show fits to the Hill equation (Supplementary Note 8).