Visual detection of bacterial and viral pathogens with peroxidase-like deoxyribozymes

More than ever, rapid and precise methods for detection of bacterial and viral pathogens are requested by our crowded society. In this study, we have detected label-free NASBA RNA amplicons of human pathogens using two sensing systems: binary (split) peroxidase-like deoxyribozyme (Dz) and a cascade of RNA-cleaving and peroxidase-like Dz. We accomplished detection of Escherichia coli and Streptococcus pneumoniae, as well as the DNA virus from Herpes group, HSV1. The sensitivity of the system was as low as 10 bacterial or 10 virus infected cells. The method requires regular boiling-water bath, 1.5 h of total time and 30 min hands-on time for split technology and around 3 h total time with 1 h 30 min hands-on time for cascade sensor with obvious benefits and binary sensor usability. The total cost of reagents and disposables is no more than 1 $ per test. This study demonstrates that both methods can be used for selective and costefficient detection of human pathogens with naked eye. The study lays a foundation for point-of-care diagnostics of infectious diseases with instrument-free visual output signal.