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 urchinlike 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.