Biomineralization-inspired artificial clickase for portable click SERS immunoassay of Salmonella enterica serovar Paratyphi B in foods

Inspired by a biomineralization behavior, we prepared a nanoflower-like artificial clickase (namely LCN clickase) for portable and sensitive click SERS immunoassay of foodborne bacterial pathogen. Encouraged by its high click catalytic activity to trigger Cu(I)-catalyzed azide-alkyne cycloaddition reaction, LCN clickase was successfully used for establishing a novel click SERS immunoassay by combining the clickase-mediated SERS signal variation at Raman-silent region. The developed method not only effectively eliminated the interferences between Raman reporter and biological species, but also reduced the complex sample matrix interference. Compared with traditional CuAAC-based immunoassays, the established method avoided the superfluous dissolution process of nanocatalysts and eliminated the requirement of reducing agent during detection, thereby shortening detection time and improving detection reliability. Impressively, the proposed method showed high selectivity and sensitivity for detection of Salmonella enterica serovar Paratyphi B with a low LOD of 20 CFU/mL, exhibiting a great potential in detection of foodborne bacterial pathogen in food samples.