A fully automated microfluidic-based electrochemical sensor for real-time bacteria detection

A fully automated microfluidic-based electrochemical biosensor was designed and manufactured for pathogen detection. The quantification of Escherichia coli was investigated with standard and nanomaterial amplified immunoassays in the concentration ranges of 0.99 × 10⁴3.98 × 10⁹ cfu mL^-1 and 103.97 × 10⁷ cfu mL^-1 which resulted in detection limits of 1.99 × 10⁴ cfu mL^-1 and 50 cfu mL^-1, respectively. The developed methodology was then applied for E. coli quantification in water samples using nanomaterial modified assay. Same detection limit for E. coli was achieved for real sample analysis with a little decrease on the sensor signal. Cross-reactivity studies were conducted by testing Shigella, Salmonella spp., Salmonella typhimurium and Staphylococcus aureus on E. coli specific antibody surface that confirmed the high specificity of the developed immunoassays. The sensor surface could be regenerated multiple times which significantly reduces the cost of the system. Our custom-designed biosensor is capable of detecting bacteria with high sensitivity and specificity, and can serve as a promising tool for pathogen detection.