Metal-organic framework (MOF) nanocomposites have recently gained intensive attention in biosensing and disease therapy owing to their outstanding physiochemical properties. However, the direct growth of MOF nanocomposites is usually hindered...

Rapid and sensitive detection of foodborne bacteria is of great significance in guaranteeing food safety and preventing foodborne diseases. A bifunctional Au@Pt core−shell nanozyme with excellent catalytic properties and high surface-enhanced Raman scattering (SERS) activity was developed for the highly sensitive detection of Salmonella typhimurium based on a label-free SERS strategy. The ultrathin Pt shell (about 1 nm) can catalyze Raman-inactive molecules into Raman-active reporters, greatly amplifying the amount of signal molecules. Moreover, the Au core serves as an active SERS substrate to enhance the signal of reporter molecules, further significantly improving the detection sensitivity. Benefiting from the excellent properties, such a bifunctional Au@Pt nanozyme was integrated with a magnetic immunoassay to construct a label-free SERS platform for the highly sensitive detection of S. typhi with a low detection limit of 10 CFU mL −1 . Also, the Au@Pt-based SERS platform exhibited excellent selectivity and was successfully utilized for the detection of S. typhi in milk samples by a portable Raman spectrometer. Our demonstration of the bifunctional nanozyme-based SERS strategy provides an efficient pathway to improve the sensitivity of labelfree SERS detection of pathogens and holds great promise in food safety, environmental analysis, and other biosensing fields.

The fabrication of a silver nanoparticles/chitosan/carbon nanotubes modified screen-printed carbon electrode (SPCE) as a highly sensitive platform for ultratrace mercury (II) detection was reported here. Silver nanoparticles (AgNPs) were synthesized by chitosan (CS) and carbon nanotube (CNT) hybrids with a green way. Chitosan trapped AgNPs anchoring on the sidewalls of the CNT arrange the nanoscale silver electrode arrays. Hg/Ag amalgam was formed on the surface of AgNPs/CS/CNT modified SPCE by depositing the mercury species to elemental mercury. Hg(II) detection is achieved by the stripping both Hg0 and Ag0 at +0.16V in the supporting electrolyte (0.1M HCl and 0.1 M KCl). This selective and sensitive detection method exhibits an excellent linear Hg(II) concentration range of 1.0 nM to 12.6 nM and a low detection limit of 0.4nM with R2 = 0.982 (n=13). The newly designed electrode has been successfully employed to measure Hg(II) in the textile samples with a good stability. The method demonstrates acceptable reproducibility and precision.