Integration of logic gates to CRISPR/Cas12a system for rapid and sensitive detection of pathogenic bacterial genes

For the first time, three 2-input elementary AND, OR, INHIBIT logic gates have been constructed by using CRISPR-Cas12a system. These logic gates utilised the intrinsic advantages of programmability, sequence specificity and high base resolution of CRISPR-Cas12a system. Among them, the AND gate owned the potentials as a built-in biosensor that responded rapidly to external pathogenic bacteria such as Staphylococcus aureus with high sensitivity and specificity. We applied the CRISPR-Cas12a based bacterial detection after a target-amplification using PCR. The total sample-to-answer time was appropriately 2.0 h, the limit of detection (LOD) was 10³ CFU/mL, and the dynamic range was 10³-10⁷ CFU/mL. Also, the sequence addressability enabled this AND logic gate to accurately trace back and distinguish input genes. These above-mentioned features were highly ideal to incur a rapid response to pathogenic bacteria for decision making. Our results not only validated the possibility of using CRISPR-Cas systems for constructing bio-computing devices but also provided a prototype of biosensor for rapid and intelligent pathogenic bacteria detection.