Label-Free Electrochemical Detection of <i>S. mutans</i> Exploiting Commercially Fabricated Printed Circuit Board Sensing Electrodes

Abstract

This paper reports for the first time printed-circuit-board (PCB)-based label-free electrochemical detection of bacteria. The demonstrated immunosensor was implemented on a PCB sensing platform which was designed and fabricated in a standard PCB manufacturing facility. Bacteria were directly captured on the PCB sensing surface using a specific, pre-immobilized antibody. Electrochemical impedance spectra (EIS) were recorded and used to extract the charge transfer resistance (Rct) value for the different bacteria concentrations under investigation. As a proof-of-concept, Streptococcus mutans (S. mutans) bacteria were quantified in a phosphate buffered saline (PBS) buffer, achieving a limit of detection of 103 CFU/mL. Therefore, the proposed biosensor is an attractive candidate for the development of a simple and robust point-of-care diagnostic platform for bacteria identification, exhibiting good sensitivity, high selectivity, and excellent reproducibility.

Keywords

• electrochemical impedance spectroscopy
• immunosensor
• direct bacteria detection
• lab-on-PCB (printed-circuit-board)
• <i>Streptococcus mutans</i> (<i>S. mutans</i>)