Motorized DNAzymes Drive Enhanced Electrochemical Biosensing for Rapid Bacterial Detection.

Self-propelled micromotors hold great promise for improving the performance of electrochemical biosensors by overcoming mass transport limitations inherent to target recognition on electrode surfaces. However, the successful integration of micromotors in electrochemical biosensors for the analysis of crude biological samples has remained elusive. In this study, we introduce the Motolyzer, a micromotor-based assay that utilizes DNAzymes for the identification and detection of bacterial targets in crude biological samples. In this system, immobilized DNAzymes are propelled by magnetic-layered micromotors within biological samples. Upon encountering their specific targets, these DNAzymes release redox DNA barcodes, which are subsequently analyzed using electrochemical chips. The Motolyzer significantly enhances the target-to-blank ratio of the biosensor (4.5 times) and achieves a limit-of-detection of 2 × 104 CFU mL-1 for Legionella pneumophila, a slow-growing bacterium, within 1 h, thereby eliminating the need for bacterial culture. Notably, the Motolyzer exhibits high specificity against non-target bacterial strains as well as non-bacterial metabolites, establishing it as a reliable, rapid assay for the identification of specific bacteria in crude biological samples. The versatility of this approach opens promising avenues for the rapid detection of various pathogens and biomarkers in both clinical and environmental settings.