Functional rolling circle amplification-based sensitive determination and low-speed centrifugation-based isolation of Staphylococcus aureus

The ability to quickly and accurately analyze Staphylococcus aureus (S. aureus) and isolate the bacteria in a simplified setting is crucial for the early identification and treatment of infectious illnesses. Here, we describe the development of a new aptamer-based detection and separation technique that combines Mg2+-dependent DNAzyme amplification cascades with catalytic hairpin assembly for enhanced sensitivity. This technique uses a rolling circle amplification procedure to build a detection scaffold with a repetitive functional hairpin structure that, upon identifying S. aureus, can launch a catalytic hairpin assembly-mediated DNAzyme-based cascade signal amplification. This allows S. aureus to be isolated using low-speed centrifugation and simultaneously quantified. The approach has a low limit of detection of 21 cfu/mL and a broad detection range of six orders of magnitude due to the inclusion of the catalytic hairpin assembly for signal amplification. In addition to high sensitivity, the method also demonstrates high selectivity for the identification and isolation of S. aureus, making it a useful instrument for reporting S. aureus infections.