Waveguide immunosensor with coating chemistry and providing enhanced sensitivity
AssigneeUniversity of Utah Research Foundation
InventorsJames N. Herron, Douglas A. Christensen, Karin D. Caldwell, Vera Janatova, Shao-Chie Huang, Hsu-Kun Wang
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Abstract
Methods and apparatus for evanescent light fluoroimmunoassays are disclosed. The apparatus employs a planar waveguide and optionally has multi-well features and improved evanescent field intensity. The preferred biosensor and assay method have the capture molecules immobilized to the waveguide surface by site-specific coupling chemistry. Additionally, the coatings used to immobilize the capture molecules provide reduced non-specific protein adsorption.
Claims33
An apparatus for performance of fluorescence immunoassays, comprising
- a light source providing a light beam in a desired wavelength range;
- a biosensor including
- a sample reservoir for containing a sample solution, said sample solution comprising a buffer, a plurality of molecules of a selected analyte, and a plurality of tracer molecules,
- an optically conductive waveguide having at least one surface disposed within said reservoir in contact with said sample solution, said at least one surface having a plurality of capture molecules immobilized thereon, said capture molecules having a binding site which selectively binds said selected analyte, and
- a lens attached or integrally formed on said waveguide and operably positioned to focus light received from said light source onto said waveguide;
- channeling means functionally positioned between said light source and said biosensor for channeling said light from said light source to said lens;
- and
- detection means operably disposed for detecting fluorescence emitted by said tracer molecules of said biosensor.
A biosensor for use with a fluorescence immunoassay system having a light source producing a light beam, means for directing the light beam to irradiate a biosensor, means for collecting a tracer light signal from said biosensor, and detection means for detecting a tracer light signal reflective of analyte in contact with the biosensor, the biosensor comprising:
- reservoir means for holding one or more test solutions, comprising at least one reservoir having walls;
- a waveguide positioned to constitute one of said walls of said reservoir, having a receiving end for receiving a light beam and first and second planar surfaces spaced from each other by a distance, and disposed perpendicularly adjacent said receiving end;
- a plurality of analyte binding molecules immobilized to one of said planar surfaces of said waveguide;
- and
- focusing means mounted to said reservoir and positioned with respect to said waveguide for receiving and focusing a light beam onto said receiving end of said waveguide.
In an apparatus for performing a fluorescence binding assay, said apparatus including a light source producing a light beam;
- a biosensor comprising a reservoir, a waveguide substrate disposed within said reservoir with an end positioned to receive light from said light beam, and a plurality of binding molecules attached to said substrate and constructed to bind a selected analyte;
- means for directing the light beam to irradiate the biosensor;
- means for collecting fluorescent light from the biosensor;
- and detection means for measuring fluorescent light output by the biosensor;
- the improvement comprising:
- said waveguide being configured as a planar element having two opposing planar surfaces and a light-receiving end;
- and
- said biosensor further including
- focusing means mounted to said reservoir and positioned with respect to said waveguide for receiving and focusing the light beam onto said light-receiving end of said waveguide.
A system for performing fluorescence immunoassays, comprising
- a light source providing a light beam;
- a reagent solution comprising a plurality of tracer molecules in solution in an appropriate buffer, said tracer molecules being operable to emit fluorescent light in response to irradiation with light from said light beam;
- a biosensor including
- a sample reservoir for holding a sample solution which comprises a sample having a plurality of analyte molecules of a selected analyte appropriately diluted in said sample solution,
- an optically conductive waveguide having at least one surface disposed within said reservoir in contact with said sample solution, said surface having a plurality of capture molecules immobilized thereon, said capture molecules each having a binding site which selectively binds one of said analyte molecules, and
- a lens attached or integrally formed on said waveguide and operably positioned to focus light received from said light source onto said waveguide;
- channeling means functionally positioned between said light source and said biosensor for channeling said light from said light source to said biosensor;
- and
- detection means operably disposed for detecting fluorescence emitted from said tracer molecules.
Dependencies are inferred from the claim text.