ULTRASENSITIVE COMPETITIVE IMMUNOASSAYS USING OPTICAL WAVEGUIDES

摘要

Sensitivity of a competitive immunoassay optical sensor is increased by selecting a tag or altering the attachment of a tag to an antigen so that the binding of tagged antigen to an antibody is decrease relative to the binding of untagged antigen to the antibody. The indicator material is selected of a suitable size or the indicator material is attached to the antigen through a long chain high molecular weight compound, or the indictor material is attached directly to the antigen with a long chain high molecular weight compound attached elsewhere to the antigen. Pretreatment of the antigen/bound tagged antigen to remove unbound antigen, and optical isolation of the substrate also increase sensitivity. If the tag can not be attached to the antigen, it is attached to the antibody. The tag is selected or attached to increase sensitivity to antigen.