HPV-16 DNA detection in clinical samples by using the EFE electrochemical CRISPR biosensor after RPA pre-amplification. A) Electrochemical response curves of the EFE electrochemical CRISPR biosensor for HPV-16 DNA detection in clinical samples. B) Normalized electrochemical current of the EFE electrochemical CRISPR biosensor for HPV-16 DNA detection in clinical samples. S1, S2, S4, and S5 are positive clinical samples. S3 and S6 are negative samples. PC and NC are, respectively, the positive and negative controls. Error bars represent the means ± s.d. from three replicates (n = 3).