A novel, proof-of-concept electrochemical impedimetric biosensor based on extracellular matrix protein-adhesin interaction

This work presents a novel perspective for electrochemical biosensors based on the detection of the interaction between extracellular matrix proteins and bacterial adhesins. Two types of impedimetric biosensors using collagen as a bioreceptor were investigated for their ability to detect pathogen adhesion using a well-characterised system of collagen-binding to recombinant E. coli expressing adhesin. First, a collagen-polymer-matrix-based biosensor was shown to detect whole bacteria in buffer media over the range 8 × 10⁵ cfu to 8 × 10⁷ cfu in a 10 µL sample. Second, a step-by-step full optimised biosensor based on direct collagen attachment showed bacterial detection over the range of 8 × 10⁴ cfu to 8 × 10⁷ cfu in a 10 µL sample. Electrochemical impedance spectroscopy and cyclic voltammetry were employed to assess the binding, which was corroborated by fluorescence binding assays. Up to now, a wide range of bioreceptors have been used in biosensor fabrication, including antibodies, oligonucleotides, phages and molecularly imprinted polymers. In this study, we show that extracellular matrix proteins can also be used for whole pathogen recognition by binding to adhesins.