Superfund Research Program
Enzyme Amplified, Complex Linked, Competitive and Non-Competitive Assays for the Detection of Metal Ions
Patent Status: Issued
Authors: Hammock, B.D., F. Szurdoki, H. Kido
Methods of assaying for the presence or amount of a metal ion in a sample suspected of containing such ions. In one aspect, an enzyme amplified sandwich assay is provided which relies upon the ability of the analyte (metal ion) to form a complex with two complexing agents (chelators). In this assay, the first sandwich chelator is immobilized on a solid support, while the second sandwich chelator is linked to a reporter group (e.g., an enzyme). This assay combines the specific recognition of the analyte by the first and second sandwich chelators with the great signal amplification offered by the reporter group (e.g., enzyme). In another aspect, a competitive assay is provided that relies on the competitive inhibition of complex formation between the coating ligand (i.e., the chelator attached to the solid support) and the organometallic compound attached to the reporter group (e.g., enzyme) by the metal ions of interest present in the sample. Using the methods of the present invention, hazardous metals, environmental pollutants, and other biomolecules can be selectively detected at ppb/ppt concentrations. More particularly, using the methods of the present invention, highly toxic metals (mercury, lead, cadmium, etc.) that pose serious human and environmental health hazards can be selectively detected at ppb/ppt concentrations. The methods of the present invention are particularly useful because they do not require the use of high affinity, highly specific antibodies which are expensive and difficult to produce.
- University of California-Davis: Immunoassays for Human and Environmental Health Monitoring