Rapid electrochemical quantification of Salmonella Pullorum and Salmonella Gallinarum based on glucose oxidase and antibody-modified silica nanoparticles

In this article, a facile and sensitive electrochemical method for quantification of Salmonella Pullorum and Salmonella Gallinarum ( S. Pullorum and S. Gallinarum) was established by monitoring glucose consumption with a personal glucose meter (PGM). Antibody-functionalized magnetic nanoparticles (IgG-MNPs) were used to capture and enrich S. Pullorum and S. Gallinarum, and IgG-MNPs- S. Pullorum and IgG-MNPs- S. Gallinarum complexes were magnetically separated from a sample using a permanent magnet. The trace tag was prepared by loading polyclonal antibodies and high-content glucose oxidase on amino-functionalized silica nanoparticles (IgG-SiNPs-GOx). With a sandwich-type immunoassay format, IgG-SiNPs-GOx were added into the above mixture solution and conjugated to the complexes, forming sandwich composites IgG-MNPs/ S. Pullorum and S. Gallinarum/IgG-SiNPs-GOx. The above sandwich composites were dispersed in glucose solution. Before and after the hydrolysis of glucose, the concentration of glucose was measured using PGM. Under optimal conditions, a linear relationship between the decrease of glucose concentration and the logarithm of S. Pullorum and S. Gallinarum concentration was obtained in the concentration range from 1.27 × 10 2 to 1.27 × 10 5  CFU mL −1 , with a detection limit of 7.2 × 10 1  CFU mL −1 (S/ N  = 3). This study provides a portable, low-cost, and quantitative analytical method for bacteria detection; thus, it has a great potential in the prevention of disease caused by S. Pullorum and S. Gallinarum in poultry. A schematic illustration of the fabrication process of IgG-SiNPs-GOD nanomaterials ( A ) and IgG-MNPs ( B ) and experimental procedure of detection of S. Pullorum and S. Gallinarum using GOD-functionalized silica nanospheres as trace tags based on PGM ( C ).