Poly(MAA-PEGMA)-coated superparamagnetic nanoparticles-based magnetic affinity immunoassay for detection of interleukin-6

Using poly(MAA-PEGMA)-coated superparamagnetic nanoparticles (PMNPs) as carrier, a rapid and sensitive immunoassay for quantitative determination of interleukin-6 (IL-6) has been developed for the first time. This protocol involved a sandwich format in which the IL-6 in samples was first captured by the primary monoclonal antibody (mAb) immobilized on the surface of PMNPs, and then recognized by the second monoclonal antibody labeled with horseradish peroxidase (HRP-mAb). The HRP-mAb dilution and immunoreaction time were examined and optimized. The linear range for IL-6 assay was 3.2-1000 pg mL^-1, and the Limit Of Detection (LOD) was 1.0 pg mL^-1. The developed immunoassay method showed high precision, high sensitivity, acceptable recovery and relatively good reliability, and could be used to detect serum IL-6 levels with consistent results in comparison with those obtained by the Enzyme-Linked Immunosorbent Assay (ELISA) method.