A sensitive and rapid immunoassay for mycoplasma pneumonia based on Fe3O4 nanoparticles

Abstract

The peroxidase-like activity of dissolved Fe3O4 magnetic nanoparticles (MNPs) was determined and compared with whole Fe3O4 MNPs in this study. We detected the peroxidase-like activity of Fe3O4 MNPs through the catalytic reaction between Fe3O4 MNPs and TMB. Due to the high catalytic activity of ferric ions and ferrous ions released from Fe3O4 MNPs after dissolution, dissolved Fe3O4 MNPs showed much better peroxidase-like activity than whole Fe3O4 MNPs. In addition, we used the peroxidase-like activity of Fe3O4 MNPs in the diagnosis of mycoplasma pneumonia infection in which Fe3O4 MNPs was used as substitution of horseradish peroxidase. Both Fe3O4 MNPs modified with amino groups (MNPs-NH2) and Fe3O4 MNPs modified with polyethyleneimine (MNPs-PEI) were successfully used in the indirect immunoassay for the detection of mycoplasma pneumoniae. And the results of dissolved Fe3O4 MNPs were more sensitive and specific than that of whole Fe3O4 MNPs.