Combining tag-specific primer extension and magneto-DNA system for Cas14a-based universal bacterial diagnostic platform

Nucleic acid-based diagnosis using CRISPR-Cas associated enzymes is essential for rapid infectious disease diagnosis and treatment strategies during a global pandemic. The obstacle has been blossomed CRIPSR-Cas based tools that can monitor wide range of pathogens in clinical samples with ultralow concentrations. Here, a universal nucleic acid magneto-DNA nanoparticle system was exploited for the detection of pathogenic bacteria, based on the collateral cleavage activity of CRISPR-Cas14a and tag-specific primer extension. In the system, the target nucleic acids were amplificated and be separated from mixtures by streptavidin-coated magnetic bead. The collateral cleavage activity of CRISPR-Cas14a can be activated via the tag sequence on the target product. Consequently, the fluorophore quencher reporter can be activated by CRISPR-Cas14a, leading to the increasing response. The exploited universal bacterial diagnostic can distinguish six different bacteria strains with 1 cfu/mL or 1 aM sensitivity, which may provide new strategies to construct fast, accurate, cost-effective and sensitive diagnostic tools in environments with limited resources.