A multi-mode vertical flow immunofiltration detection system based on multifunctional PB@Au NPs for highly sensitive and diversified detection of brucellosis antibodies.

A multi-mode immunofiltration detection assay is introduced, which uses Prussian blue-gold nanocomposites (PB@Au NPs) as nanoprobes and integrates four signal output modes: colorimetric (CM), enzymatic catalysis (CL), photothermal (PT), and surface-enhanced Raman scattering (SERS). Rapid vertical flow technology (RVFT) serves as the detection platform, achieving highly sensitive, qualitative, and diversified quantitative detection of brucellosis antibodies. First, PB@Au NPs were successfully synthesized using the wet chemical method, exhibiting excellent catalytic activity, a PT conversion efficiency of 36.2%, and strong Raman signal enhancement. These nanoprobes were then used to construct PB@Au-RVFT for brucellosis detection. In CM mode, the detection limit was 10 IU·mL⁻¹, which decreased to 4 IU·mL⁻¹ with enzyme-mediated CM amplification. PT and SERS modes further improved sensitivity, reaching detection limits of 0.167 and 0.144 IU·mL⁻¹, respectively, which are significantly better than traditional colloidal gold test strips. Additionally, the recovery rates for spiked clinical serum samples ranged from 94.59 to 105.31%, confirming the reliability of the method for practical applications. The proposed method enables multi-signal collaborative detection, enhancing anti-interference capacity and accuracy in complex samples. Its adaptability various detection environments give this technology the potential to conduct early screening and precise control of brucellosis in resource-poor areas. Meanwhile, it also provides a flexible and highly sensitive diagnostic strategy for other infectious diseases.