Immobilization of dengue specific IgM antibodies on magnetite nanoparticles by using facile conjugation strategies

IgM antibodies are the first immunoglobulin isotype to appear in several diseases like dengue fever. In this study, five different strategies to conjugate dengue specific IgM antibodies on magnetite nanoparticle surface (Fe₃O₄) were evaluated through commercial IgM antibody-capture ELISA assay for dengue diagnosis. IgM-Fe₃O₄ conjugates were obtained by using physical interactions, covalent bonding and antibody-antigen interactions. In all cases, analytical responses of IgM-Fe₃O₄ conjugates were higher than that of traditional ELISA assay. The most effective conjugation strategy was achieved by antigen-antibody interaction with fluorescence intensity almost 20 times higher than standard ELISA. The results discussed herein illustrate the potential application of magnetite nanoparticles as a new platform for IgM immunoassay.