Sapidyne Instruments Inc.

Other

Steve J Lackie

Thomas R Glass

Myron J Block

The present invention provides an improved system for detecting the presence or level of an analyte in a sample. In 'competition-like' assays of the present invention, a sample including an analyte is mixed with a second ligand to which the analyte binds, and the mixture is exposed to a solid phase containing a first ligand that can compete with the analyte for binding to the second ligand. According to the present invention, the time of exposure of the mixture to the solid phase is limited so that substantially no dissociation of analyte/second ligand complex occurs. The competition-like assays of the present invention are preferably performed with a solid phase containing a substantial excess of first ligand. In 'sandwich-type' assays of the present invention, a sample including an analyte is contacted with a solid phase including a first ligand that binds the analyte and, simultaneously or subsequently, is contacted with a second ligand that binds the analyte (or the analyte/first ligand complex). The time of contact between the second ligand and the solid phase is limited so that substantially no non-specific binding between the second ligand and the solid phase occurs.

Solid phase assay for detection of ligands

The present invention provides an improved system for detecting the presence or level of an analyte in a sample. In &ldquo;competition-like&rdquo; assays of the present invention, a sample including an analyte is mixed with a second ligand to which the analyte binds, and the mixture is exposed to a solid phase containing a first ligand that can compete with the analyte for binding to the second ligand. According to the present invention, the time of exposure of the mixture to the solid phase is limited so that substantially no dissociation of analyte/second ligand complex occurs. The competition-like assays of the present invention are preferably performed with a solid phase containing a substantial excess of first ligand. In &ldquo;sandwich-type&rdquo; assays of the present invention, a sample including an analyte is contacted with a solid phase including a first ligand that binds the analyte and, simultaneously or subsequently, is contacted with a second ligand that binds the analyte (or the analyte/first ligand complex). The time of contact between the second ligand and the solid phase is limited so that substantially no non-specific binding between the second ligand and the solid phase occurs.

An assay apparatus employing total internal reflection of excitation radiation at the interface between a replaceable optically conductive rod or fiber and a surrounding liquid phase of lower index of refraction. Immobilized on the surface of the fiber is a component of a complex formed in an immunological-type specific reaction. A fluorophore that can be excited into fluorescence by the excitation radiation is attached to another component of the complex. The rod is coaxially mounted within a tube that is sized with respect to said rod so that a fluid sample may be introduced into said tube. The rod and tubing are supported in a mounting assembly that is attachable to an optical assembly for transmitting excitation radiation into the proximal end of the rod and receiving fluorescent radiation emitted from the proximal end of the rod. Included in the apparatus is a mounting assembly for centering the rod within tube and for biasing the rod in a first direction against an annular seat. The latter is designed to support one end of the rod so that none of the radiation introduced into the rod is intercepted by the seat. The apparatus also includes a seal arrangement for preventing a fluid sample from escaping from the tube. Additionally, a tapered fiber may be included in the optical system of the assay apparatus for increasing the power and numerical aperture of radiation input into the optical rod.

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Boise, ID, United States of America

Steve J Lackie