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Abstract
Enterohemorrhagic (EHEC) and enteropathogenic (EPEC) Escherichia coli strains pose significant health risks but are difficult to detect in environmental samples due to low abundance and reliance on time-consuming culture methods. This study evaluated the Sharp Laboratories of America (SLA) impedimetric biosensor platform for rapid, real-time detection of E. coli virulence genes—stx (EHEC), hly (EPEC), and adk (universal E. coli marker)—using DNA-DNA hybridization. The SLA system measures impedance changes during nucleic acid binding, enabling sensitive and specific detection of single-stranded versus double-stranded DNA. Successive platform iterations improved electrode design, assay throughput, and signal resolution. In collaboration with the Center for Coastal Margin Observation and Prediction (CMOP), this research optimized hybridization assays for pathogenic and non-pathogenic E. coli strains, supporting development of field-based biosensors for environmental monitoring. These findings demonstrate the potential of impedimetric detection for high-resolution, near real-time pathogen surveillance in aquatic ecosystems.