To establish a method for rapid detection of Vibrio parahaemolyticus producing thermostable direct haemolysin (TDH) by immunochromatography technology of the labeled magnetic fluorescent nanoparticles combined with antibody. To establish a method for rapid detection of Vibrio parahaemolyticus producing thermostable direct haemolysin (TDH) by immunochromatography technology of the labeled magnetic fluorescent nanoparticles combined with antibody.Methods The gene fragment of Vibrio parahaemolyticus producing TDH was constructed and amplified. The product was ligated with plasmid vector (pET-28a) and expressed in Escherichia coli to prepare antibody. The antibody was conjugated with the labeled magnetic fluorescent nanoparticles to prepare an immunochromatographic test strip. The samples were mixed with different concentrations of standard strain and negative control samples respectively with the fluorescent nanoparticle-monoclonal antibody conjugate, incubated on the strip for 5 min, and observed with naked eyes under UV light.Experimental test was conducted for sensitivity, specificity, reproducibility and sample simulation. The gene fragment of Vibrio parahaemolyticus producing TDH was constructed and amplified. The product was ligated with plasmid vector (pET-28a) and expressed in Escherichia coli to prepare antibody. The antibody was conjugated with the labeled magnetic fluorescent nanoparticles to prepare an immunochromatographic test strip. The samples were mixed with different concentrations of standard strain and negative control samples respectively with the fluorescent nanoparticle-monoclonal antibody conjugate, incubated on the strip for 5 min, and observed with naked eyes under UV light.Experimental test was conducted for sensitivity, specificity, reproducibility and sample simulation.Results The recombinant plasmid vector could efficiently and efficiently express the soluble protein with molecular weight of 26 kD in Escherichia coli BL21 (DE3). The monoclonal antibody and the magnetic fluorescent particles were well coupled. The resulting conjugate was reacted with the lowest concentration at 10 CFU/ml positive strain, and the negative control strains had no reaction. The recombinant plasmid vector could efficiently and efficiently express the soluble protein with molecular weight of 26 kD in Escherichia coli BL21 (DE3). The monoclonal antibody and the magnetic fluorescent particles were well coupled. The resulting conjugate was reacted with the lowest concentration at 10 CFU/ml positive strain, and the negative control strains had no reaction.Conclusion The magnetic fluorescent nanoparticles coupled with the TDH virulence gene expression product of Vibrio parahaemolyticus was prepared in the experiment.Testing process was simple with high sensitivity, strong specificity, good repeatability and short detection time. The magnetic fluorescent nanoparticles coupled with the TDH virulence gene expression product of Vibrio parahaemolyticus was prepared in the experiment.Testing process was simple with high sensitivity, strong specificity, good repeatability and short detection time.