Application of Gold Core-Shell Magnetic Nanoparticles as an Immunosensor for the Detection of Vibrio cholerae

Introduction: For rapid and sensitive detection of Vibrio cholerae an accurate assay is needed. In the present study, a gold-coated magnetic nanoparticle (GMNP) was investigated for the detection of V. cholerae. Materials and Methods: GMNPs were synthesized and functionalized by 11-mercapto-undecanoic acid (MUA) as a linker for immobilization of IgG against V. cholerae OmpW antigen. In the next step, IgG was coupled with carboxylic group of MUA using EDC / NHS and the IgG/GMNPs nanocomposite created and finally, the bacterium was detected in a sandwich model ELISA. Results: The IgG/GMNPs nanocomposite could detect V.cholerae in a concentration range from 2.5×10-2 to 1.5 × 105 N/ml (number of V.cholerae per ml). The correlation coefficient was 0.99 and the detection limit was 16 N/ml. Conclusions: In this study, the procedure of antibody immobilization on magnetic nanoparticles was designed. So that, by using magnetic nanoparticles, the pre-concentration as a time-consuming step was removed and the sensitivity of V. cholerae determination was increased. Also, this method can be extended to detect other microorganisms.