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 (IgG(1)) was conjugated on surface magnetic nanoparticles (MNPs) to form MNP-IgG(1). Secondary polyclonal antibody (IgG(2)) and Horseradish Peroxidase enzyme were conjugated on silica nanoparticles (SNPs) to form HRP-SNP-IgG(2). HRP-SNP-IgG(2). MNP-IgG(1) and HRP-SNP-IgG(2) were added to B. abortus. The MNP-IgG(1)-B.abortus-IgG(2)-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-IgG(2) and MNP-IgG(1) size and structure were 35, 44, 60 and 56 nm, respectively. In addition, a good linear correlation was observed at 10(2)-10(7) CFU mL(-1) concentrations, which their linear equation and regression were Y=0.3x+ 0.18 and R-2 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. (c) 2019 Elsevier B.V. All rights reserved.