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Detection of Multiple Pathogens in Serum Using Silica-Encapsulated Nanotags in a Surface-Enhanced Raman Scattering-Based Immunoassay

Neng, Jing, Li, Yina, Driscoll, Ashley J., Wilson, William C., Johnson, Patrick A.
Journal of agricultural and food chemistry 2018 v.66 no.22 pp. 5707-5712
Raman spectroscopy, Rift Valley fever virus, West Nile virus, Yersinia pestis, antigen-antibody complex, antigens, detection limit, disease surveillance, fetal bovine serum, immunoassays, magnetism, nanoparticles, pathogens, polyclonal antibodies
A robust immunoassay based on surface-enhanced Raman scattering (SERS) has been developed to simultaneously detect trace quantities of multiple pathogenic antigens from West Nile virus, Rift Valley fever virus, and Yersinia pestis in fetal bovine serum. Antigens were detected by capture with silica-encapsulated nanotags and magnetic nanoparticles conjugated with polyclonal antibodies. The magnetic pull-down resulted in aggregation of the immune complexes, and the silica-encapsulated nanotags provided distinct spectra corresponding to each antigen captured. The limit of detection was ∼10 pg/mL in 20% fetal bovine serum, a significant improvement over previous studies in terms of sensitivity, level of multiplexing, and medium complexity. This highly sensitive multiplex immunoassay platform provides a promising method to detect various antigens directly in crude serum samples without the tedious process of sample preparation, which is desirable for on-site diagnostic testing and real-time disease monitoring.