An innovative immunochromatographic assay employing Pt-Pd bimetallic nanoparticles as labels for the detection of foot-and-mouth disease virus serotype O

Abstract

Objective: We created a novel, high sensitivity immunochromatographic assay that allows for clear and precise quantitative analysis by employing innovative bimetallic nanoparticles with peroxide-like activity as markers for the preparation of the test strip.

Methods: Initially, we synthesized Pt-Pd bimetallic nanoparticles through the reduction of K₂PtCl₄ and Na₂PdCl₄ using ascorbic acid (AA) in an ultrasonic water bath. These bimetallic nanoparticles were then utilized to label purified antigens from the foot-and-mouth disease virus (FMDV) type O (FMDV-146S), resulting in the creation of antigen-captured nanomarkers. Upon completion of the antigen-antibody reaction, we introduced a color-developing agent (3,3',5,5'-tetramethylbenzidine) for cascade amplification, significantly enhancing detection sensitivity while ensuring clear and accurate quantitative analysis.

Results: The quantitative detection sensitivity achieved was 1:2⁸/test, with a linear range spanning from 1:2⁶ ∼ 1:2⁹ /test. For FMDV type O positive serum, the detection sensitivity reached 96.7 %. Furthermore, this method exhibited a 95 % detection sensitivity for FMDV negative serum, FMDV type A and type AsiaⅠ positive sera, as well as sera positive for other common viral diseases in animals. In comparison to the OIE-recommended LPB-ELISA, this approach displayed higher correlation (correlation coefficient = 0.909). Innovation was at the core of establishing this immunochromatographic assay based on Pt-Pd bimetallic nanoparticles for the detection of FMDV antibodies.

Conclusion: The findings revealed a striking 2⁴-fold improvement in sensitivity when compared to colloidal gold, accompanied by a strong correlation coefficient (R² > 0.9). This suggests a robust and consistent linear association in the results. This method represents a significant advancement in the field of rapid immunochromatographic assays, offering a promising alternative application for bimetallic nanoparticles.

Keywords: Foot-and-mouth disease virus type O; Immunochromatographic assay; Peroxide-like; Pt-Pd bimetallic nanoparticles.