DNAzyme-integrated plasmonic nanosensor for bacterial sample-to-answer detection

Abstract Pathogenic bacteria pose a serious threat to public safety and health, and cause significant losses in the global economy and in lives. The current golden standard, culture-based method, for bacterial detection is often costly, laborious, and time-consuming (even weeks). Thus, there is an urgent need to develop rapid, reliable and easy-to-use approaches for bacterial detection. Herein, we present a new detection strategy termed as ‘ D NAzyme- I ntegrated P lasmonic N ano s ensor’ (DIPNs) that can selectively detect target bacteria in a simple, inexpensive and culture-free process, which combines real-time DNAzyme-based sensor and enzyme-responsive nanoplasmonic biosensor system. The DIPNs platform takes advantage of a bacteria-specific RNA-cleaving DNAzyme probe as the molecular recognition element and enzyme-responsive plasmonic nanoparticles’ localized surface plasmon resonance (LSPR) as the signal readout. Using Escherichia coli ( E. coli ) as a model analyte, we demonstrated that the DIPNs system can provide the fast and low concentration (down to 50 bacteria per mL) quantification of E. coli even in the complex fluids ( e.g., milk, serum, juice) with naked eyes, which would be expected for the detection of bacterial pathogens in the simple, low-cost and on-site manner.