Exonuclease III-based and gold nanoparticle-assisted DNA detection with dual signal amplification

► A dual signal amplification-assisted electrochemical DNA biosensor was developed. ► Dual signal amplification was based on the use of ExoIII and gold nanoparticles. ► The biosensor could sensitively detect target DNA at a picomolar level. ► The well specificity and reproduction of the detection were also demonstrated.