Magnetic focusing immunosensor for the detection of pathogens

• US 6,630,355 B1
• Filed: 01/02/2001
• Issued: 10/07/2003
• Est. Priority Date: 11/05/1999
• Status: Expired due to Term

• Current Assignee: Council On Postsecondary Education
• Original Assignee: Board of Governors For Higher Education State of Rhode Island, Providence Plantations
• Inventors: Pivarnik, Philip, Rand, A. Garth, Cao, He, Letcher, Stephen V.
• Primary Examiner(s): Chin, Christopher L.
• Assistant Examiner(s): Do, Pensee T.
• Application Number:
  US09/753,201
• Time in Patent Office: 1,008 Days
• Field of Search: 436/164, 436/172, 436/530, 436/532, 436/536, 436/800, 436/166, 436/805, 436/546, 436/74, 436/75, 436/501, 436/65, 436/79.81, 436/85, 436/86, 436/806, 436/533, 436/584, 435/7.5, 435/7.1, 435/287.1, 435/288.7, 435/176, 435/283.1, 435/289.1, 435/290.1, 435/7.33, 435/7.34, 435/7.35, 356/300, 356/244, 356/301, 356/303, 356/319, 356/326, 356/311, 385/123, 422/82.11
• US Class Current: 436/164
• CPC Class Codes: G01N 2021/6417 Spectrofluorimetric devices
• CPC Class Codes: G01N 2021/6484 Optical fibres
• CPC Class Codes: G01N 21/6428 Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" in vivo A61B5/00; immunoassay G01N33/53
• CPC Class Codes: G01N 21/645 Specially adapted constructive features of fluorimeters
• CPC Class Codes: Y10S 435/808 Optical sensing apparatus
• CPC Class Codes: Y10S 436/80 Fluorescent dyes, e.g. rhodamine
• CPC Class Codes: Y10S 436/805 Optical property
• CPC Class Codes: Y10S 436/806 Electrical property or magnetic property

Abstract

A magnetic focusing immunosensor for the detection of pathogens comprising a laser, an exciting fiber and a collecting fiber, a fiber optic magnetic probe in communication with the collecting and exciting fibers and means for detecting, collecting and measuring fluorescent signals in communication with the collecting fiber. The probe and the collecting and exciting fibers are configured to focus paramagnetic microspheres attached to antigen/antibody/optically labeled complexes in a predetermined pattern in the field of view of the collecting fiber while blocking background interference.

Claims

1. A method for the detection of pathogens in a sample comprising:

placing paramagnetic microspheres with immobilizing primary antibodies specific for the antigens of the pathogens in the sample;

placing optical markers bound to secondary antibodies specific for the antigens in the sample;

forming in the sample antibody/antigen/optical marker molecular complexes when pathogens are present;

subjecting the sample to a magnetic field;

concentrating in a predetermined pattern the molecular complexes in the field of view of an optically collecting fiber; and

providing a signal which corresponds to the presence of the pathogens in the analyte.

2. The method of claim 1 wherein the antibodies are anti-Salmonella.

3. The method of claim 1 wherein the pathogen is S. typhimurium.

4. The method of claim 1 wherein the sample is blood selected from the group consisting of mammals, fish and fowl.

5. A method for the detection of pathogens in a sample comprising:

placing paramagnetic microspheres with immobilizing primary antibodies specific for the antigens of the pathogens in the sample;

placing optical markers bound to secondary antibodies specific for the antigens in the sample;

forming in the sample antibody/antigen/optical marker molecular complexes when the pathogens are present;

magnetically focusing the molecular complexes in a predetermined pattern in the field of view of an optically collecting fiber; and

providing a signal which corresponds to the presence of the pathogen in the sample.

6. The method of claim 5 wherein the magnetically focusing and providing steps are substantially simultaneous.