Localized surface plasmon-enhanced electrochemiluminescence biosensor for rapid, label-free, and single-step detection of broad-spectrum bacteria using urchin-like Au and Ag nanoparticles

In this study, localized surface plasmon-enhanced electrochemiluminescence (LSP-ECL) biosensor, a new ECL enhancement way for S2O82−/O2 system, was constructed based on urchin-like Au and Ag nanoparticles (AgNPs) for fast, one-step, and label-free detection of broad-spectrum bacteria. We found plasmonic metals with small diameters contributed to the ECL enhancement. Moreover, relying entirely on the physical puncture of urchin-like Au, the bacteria could be captured to the electrode surface without the need for target recognition agents. The single-step LSP-ECL biosensor exhibited high sensitivity in the range of 102–108 CFU/mL bacteria with the detection limit as low as 52 CFU/mL, meanwhile possessing a short detection time of 30 min. What’s more, the LSP-ECL biosensing strategy achieved detection of S.aureus present in plasma samples without involving bacterial culture and nucleic acid extraction. Considering the merits of label-free, short assay time, and one-step operation, the developed LSP-ECL strategy provides a versatile and culture-free platform for pathogenic bacteria detection.