Fig. 7. Performance of Au-PEG₆-VHH-72-C13 sensor on clinical samples.

A Current response difference for nasopharyngeal swab samples from COVID-19 positive patients (n = 20) and COVID-19 negative patients (n = 20) against the golden standard, RT-PCR Ct values. Cut-off level of positivity was set at Ct = 33. Cycle threshold value of RT-PCR (grey). The current cut-off value for positive samples was set to 2 µA. Each patient sample was performed on a new electrode. The results are expressed as the mean ± SEM of 3 independent measurements for each sample. B ROC curve from clinical data and positive and negative RT-PCR identification. C Selectivity of the SARS-CoV-2 electrochemical diagnostics towards other viruses. The results are expressed as the mean ± SEM of 3 independent measurements for each sample.