Fig. 6.

Highlight of secondary binding and signal amplification approaches utilized in electrochemical biosensor-based pathogen detection. a) Four amplification approaches associated with the secondary binding of enzyme-labeled secondary antibodies: (A) electron transfer mediation; (B) nanostructuring of surface for increased rate of charge transfer kinetics; (C) conversion of electrochemically inactive substrate into a detectable electroactive product; (D) catalysis of oxidation of glucose for production of hydrogen peroxide for electrochemical detection (Kokkinos et al. 2016). b) Signal amplification via non-selective binding of AuNPs to bound bacterial target (E. coli) (Wan et al. 2016).