Ultrasensitive and amplification-free detection of SARS-CoV-2 RNA using an electrochemical biosensor powered by CRISPR/Cas13a

•A CRISPR/Cas13a-powered electrochemical biosensor is described for detecting SARS-CoV-2 RNA strands.•The biosensor employs a multiplexed and NAA-free strategy for detecting SARS-CoV-2 RNA fragments.•SARS-CoV-2 S and Orf1ab genes were detected in both synthetic and clinical samples.•The biosensor powered by CRISPR/Cas13a achieved detection limits of 2.5 and 4.5 ag/µL for the S and Orf1ab genes, respectively.•The specificity, simplicity, and universality of the biosensor may position it as a potential competitor to RT-PCR.