Study On The Application Of Magnetic Microspheres Based Chemiluminescent Immunoassay

Chemilumninescent immunoassay (CLIA) has developed since 1970s. It is an immunoassay combined by chemiluminescent reaction and immunoreaction. This technique is specific and sensitive. It also has other advantages, such as long period of validity of the labels, wide working range, easy to automation. With these advantages, the chemiluminescent immunoassay now is widely used in many fields, especially in the clinical assay, such as the detection of hepatitis, bacteria in food, tumor markers.In recent years, magnetic microspheres are most commonly used as solid carry in RIA's, ELISA's, and chemiluminescent assays. In this paper, the silica magnetic microspheres designed and made by our lab are used as the solid carriers; a chemiluminescent immunoassay method and enzyme linked immunoassay method based on magnetic microspheres are setup using hCG as the modle analyte. Through researching some critical influencing factor of detection method such as antibody density, reaction time, concentration of enzyme label antobody and microspheres dosage, this chemiluminescent immunoassay can be finished in 45min, and the CV of inter-assay and intra-assay is blow 13% and below 10% respectively. The lowest limited detection of this immunoassay is 1.42mIU/ml, and the linear working range is from 0-750mIU/ml. while, the lowest limit detection of ELISA is 2.36mIU/ml, and the linear working range is from 0 to 500mIU/ml. The detection results indicated that the above chemiluminescent immunoassay has better performance.Otherwise, on the basis of the immunoassay, different kinds of microspheres are applied in order to study the relationship between the physical & chemical properties of magnetic microspheres and the detection performance of immunoassay by changing the microspheres size, matrix of maicrospheres, blocking agent style, the structure of functional group and the density of functional group on the surface of the magnetic microspheres. A simple method which could be used to evaluate the non specific adsorption of the magnetic microspheres is developed by using the above chemiluminescent immunoassay based on magnetic microspheres. This will offer useful information to further study and develop the suitable magnetic microspheres to CLIA.