Functionalization of anti-Brucella antibody based on SNP and MNP nanoparticles for visual and spectrophotometric detection of Brucella

Abstract An Immuno-Nano-Biosensor with high sensitivity was designed based on iron and silica nanoparticles to detect B. abortus. Briefly explain, primary polyclonal antibody (IgG1) was conjugated on surface magnetic nanoparticles (MNPs) to form MNP-IgG1. Secondary polyclonal antibody (IgG2) and Horseradish Peroxidase enzyme were conjugated on silica nanoparticles (SNPs) to form HRP-SNP-IgG2. HRP-SNP-IgG2. MNP-IgG1 and HRP-SNP-IgG2 were added to B. abortus. The MNP-IgG1-B.abortus-IgG2-SNP-HRP complex was isolated from the reaction mixture using a magnet. After that, tetramethylbenzidine was added to the complex. The reaction was stopped with HCl and investigated using UV–Vis spectrophotometry. The nanoparticles' structure and size were investigated using SEM and DLS. Immuno-Nano-Biosensor sensitivity and specificity were determined. The SEM and DLS results indicated that the SNPs, MNPs, HRP-SNP-IgG2 and MNP-IgG1 size and structure were 35, 44, 60 and 56 nm, respectively. In addition, a good linear correlation was observed at 102–107 CFU mL−1 concentrations, which their linear equation and regression were Y = 0.3× + 0.18 and R2 0.982, respectively. The limitation of detecting B. abortus was 160 CFU mL−1. Finally, the results demonstrated that those designed Immuno-Nano-Biosensor could be specifically detected B. abortus and B. melitensis in real samples.