Particle assisted immunoassay

摘要

The sensitivity of particle based immunoassays is improved by including a second, larger type of particle with a smaller particle. The technique is particularly useful to extend the sensitivity range of colloidal gold immunoassays and can be used in a convenient strip format. In one embodiment, larger selenium particles are included in a sandwich type assay that uses smaller gold particles. The larger selenium particles improve the color development of the gold particles. The technique is applicable to other particle based assays where an improvement in assay sensitivity is desired.