RESUMO
Objective To develop europium (Ⅲ) [Eu (Ⅲ)] chelated microparticles for homogeneous immunoassay.Methods Anti-human PCT antibodies were labeled with Eu (Ⅲ) chelated nanoscale microparticles as the detection antibody,and another anti-human PCT antibody was labeled with biotin as the solid-phase antibody.Magnetic microspheres labeled with streptavidin were used to separate the complexes of Eu-IgM-PCT-IgM-Biotin.Results In the homogeneous immunoassay,the standard curve fit was not linear.The quadratic curve was Y =19170.12 + 75493.74X-26.00X2(r =0.9986).According to the standard curve,the limit of detection for PCT was 0.04 ng/ml.Conclusion The homogeneous immunoassay which uses Eu (Ⅲ) chelated microparticles is highly sensitive for detection of PCT recombinant antigens and may serve as a promising method to measure serum PCT levels in the future.