Liposome-enhanced immunoassay and test device

• US 6,248,596 B1
• Filed: 03/03/1998
• Issued: 06/19/2001
• Est. Priority Date: 10/12/1993
• Status: Expired due to Fees

• Current Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Original Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Inventors: Siebert, Sui Ti Atienza, Reeves, Stuart Graham, Durst, Richard Allen
• Primary Examiner(s): Chin, Christopher L.
• Application Number:
  US09/034,086
• Time in Patent Office: 1,204 Days
• Field of Search: 422/50, 422/55-58, 422/61, 422/82.01, 435/287.1, 435/287.2, 435/287.7, 435/287.9, 435/288.7, 435/805, 435/810, 435/970, 436/164, 436/169, 436/172, 436/514, 436/518, 436/528, 436/530, 436/533, 436/805, 436/806, 436/810, 436/829, 204/400, 204/403
• US Class Current: 436/518
• CPC Class Codes: G01N 33/54313 the carrier being characterised by its particulate form
• CPC Class Codes: G01N 33/5438 Electrodes
• CPC Class Codes: G01N 33/54388 based on lateral flow
• CPC Class Codes: G01N 33/558 using diffusion or migration of antigen or antibody immunochromatographic test strips G01N33/54387
• CPC Class Codes: Y10S 435/805 Test papers
• CPC Class Codes: Y10S 435/81 Packaged device or kit
• CPC Class Codes: Y10S 435/97 Test strip or test slide
• CPC Class Codes: Y10S 436/805 Optical property
• CPC Class Codes: Y10S 436/806 Electrical property or magnetic property
• CPC Class Codes: Y10S 436/807 Apparatus included in process claim, e.g. physical support structures
• CPC Class Codes: Y10S 436/81 Tube, bottle, or dipstick
• CPC Class Codes: Y10S 436/815 Test for named compound or class of compounds
• CPC Class Codes: Y10S 436/829 Liposomes, e.g. encapsulation

Abstract

A test device for detecting or determining an analyte in a test solution includes an absorbent material having separate contact, competitive binding, and measurement portions. The contact portion is positioned for contact with and uptake of the test solution. The competitive binding portion has a binding material for the analyte non-diffusively bound thereto. The measurement portion has a receptor for the analyte and marker-encapsulating liposomes non-diffusively bound thereto. In a method for using the test device, a solution containing the analyte and the analyte-liposome conjugate is allowed to traverse the absorbent material from the contact portion through the competitive binding portion and on through the measurement portion of the absorbent material. The amount of marker in the measurement portion of the absorbent material, following traversal by the test solution, is then determined as a measure of the analyte in the sample. Liposomes encapsulating an electroactive marker are used in conjunction with a test device as described above but which includes an electrochemical measurement portion in place of the measurement portion described above. Test devices and methods employing electrochemical detection or quantification of an electroactive marker corresponding to the amount of analyte in a sample may be either amperometric or potentiometric.

Claims

1. A test device for detecting or determining an analyte in a test solution, said test device comprising:

an absorbent material, comprising;

a contact portion proximate to a first end of said absorbent material for contact with and uptake of said test solution;

an electrochemical measurement portion at a location on said absorbent material which is positioned away from the first end; and

a competitive binding portion positioned between and segregated from said contact portion and said measurement portion on said absorbent material and having a binding material for the analyte non-diffusively bound to said competitive binding portion;

said electrochemical measurement portion comprising a working electrode portion and a counter electrode portion, and further comprising a reference electrode portion positioned between and segregated from said working electrode portion and said counter electrode portion on said absorbent material, wherein said working electrode portion is positioned between said competitive binding portion and said reference electrode portion on said absorbent material, said working, reference, and counter electrode portions are electrically connected with one another, and wherein either said absorbent material further comprises a liposome lysing portion positioned between said competitive binding portion and said working electrode portion, wherein said liposome lysing portion is segregated from said competitive binding portion and has a liposome lysing agent non-diffusively bound thereto, or said working electrode portion has a liposome lysing agent non-diffusively bound thereto.

2. A test device according to claim 1, said working electrode portion further having a marker accumulating agent non-diffusively bound thereto.

3. A test device for detecting or determining an analyte in a test solution, said test device comprising:

an absorbent material, comprising;

a contact portion proximate to a first end of said absorbent material for contact with and uptake of said test solution;

an electrochemical measurement portion at a location on said absorbent material which is positioned away from the first end; and

a competitive binding portion positioned between and segregated from said contact portion and said measurement portion on said absorbent material and having a binding material for the analyte non-diffusively bound to said competitive binding portion;

said electrochemical measurement portion comprising an indicator electrode portion and a reference electrode portion, wherein said indicator electrode portion and said reference electrode portion are electrically connected with one another, and said indicator electrode portion is positioned between and segregated from said competitive binding portion and said reference electrode portion on said absorbent material, and wherein either said absorbent material further comprises a liposome lysing portion positioned between said competitive binding portion and said indicator electrode portion, wherein said liposome lysing portion is segregated from said competitive binding portion and has a liposome lysing agent non-diffusively bound thereto, or said indicator electrode portion has a liposome lysing agent non-diffusively bound thereto.

4. A test device for detecting or determining an analyte in a test solution, said test device comprising:

an absorbent material, comprising;

a contact portion proximate to a first end of said absorbent material for contact with and uptake of said test solution;

an electrochemical measurement portion at a location on said absorbent material which is positioned away from the first end; and

a competitive binding portion positioned between and segregated from said contact portion and said measurement portion on said absorbent material and having a binding material for the analyte non-diffusively bound to said competitive binding portion;

said electrochemical measurement portion comprising a working electrode portion, a reference electrode portion, and a counter electrode portion, wherein each of said electrode portions is segregated from one another on said absorbent material, said working, reference, and counter electrode portions are electrically connected with one another, and wherein either said absorbent material further comprises a liposome lysing portion positioned between said competitive binding portion and said working electrode portion, wherein said liposome lysing portion is segregated from said competitive binding portion and has a liposome lysing agent non-diffusively bound thereto, or said working electrode portion has a liposome lysing agent non-diffusively bound thereto.

5. A test device according to claim 4, said working electrode portion further having a marker accumulating agent non-diffusively bound thereto.

6. A test device for detecting or determining an analyte in a test solution, said test device comprising:

an absorbent material, comprising;

a contact portion proximate to a first end of said absorbent material for contact with and uptake of said test solution;

an electrochemical measurement portion at a location on said absorbent material which is positioned away from the first end; and

a competitive binding portion positioned between and segregated from said contact portion and said measurement portion on said absorbent material and having a binding material for the analyte non-diffusively bound to said competitive binding portion;

said electrochemical measurement portion comprising an indicator electrode portion and a reference electrode portion, wherein said indicator electrode portion and said reference electrode portion are segregated from one another on said absorbent material and are electrically connected with one another, and wherein either said absorbent material further comprises a liposome lysing portion positioned between said competitive binding portion and said indicator electrode portion, wherein said liposome lysing portion is segregated from said competitive binding portion and has a liposome lysing agent non-diffusively bound thereto, or said indicator electrode portion has a liposome lysing agent non-diffusively bound thereto.