Entropy-driven amplification reaction and the CRISPR/Cas12a system form the basis of an electrochemical biosensor for E.coli-specific detection.

We present an innovative biosensor designed for the precise identification of Escherichia coli (E.coli), a predominant pathogen responsible for gastrointestinal infections. E.coli is prevalent in environments characterized by substandard water quality and can lead to severe diarrhea, especially in hospital settings. The device employs entropy-driven reactions to synthesize copious amounts of double-stranded DNA (dsDNA), which, upon binding with crRNA, triggers the CRISPR/Cas12a system's cleavage mechanism. This process results in the separation of a ferrocene (Fc)-tagged DNA strand from the electrode, enhancing the electrochemical signal for E.coli's rapid and accurate detection. Our tests confirm the biosensor's ability to quantify E.coli across a dynamic range from 100 to 10 million CFU/mL, achieving a detection threshold of just over 5 CFU/mL. The development of this electrochemical biosensor highlights its exceptional selectivity, high sensitivity, and user-friendly interface for E.coli detection. It stands as a significant step forward in pathogen detection technology, promising new directions for identifying various bacterial infections through the CRISPR/Cas mechanism.