Surface-modified wick for diagnostic test strip

• US 6,967,105 B2
• Filed: 12/02/2000
• Issued: 11/22/2005
• Est. Priority Date: 12/02/2000
• Status: Expired due to Fees

• Current Assignee: Queststar Medical, Inc.
• Original Assignee: Queststar Medical, Inc.
• Inventors: Petersen, Robert J., Hanson, August R., Kydd, Arthur R., Nomura, Hiroshi
• Primary Examiner(s): Warden, Jill
• Assistant Examiner(s): CROSS, LATOYA I
• Application Number:
  US09/728,153
• Publication Number:
  US 20020102739A1
• Time in Patent Office: 1,816 Days
• Field of Search: 422/55, 422/56, 422/58, 422/68.1, 422/73, 422/82.05, 436/69, 436/164, 436/177, 436/169
• US Class Current: 436/169
• CPC Class Codes: G01N 1/30 Staining; Impregnating ; Fixation; Dehydration; Multistep processes for preparing samples of tissue, cell or nucleic acid material and the like for analysis
• CPC Class Codes: G01N 33/558 using diffusion or migration of antigen or antibody immunochromatographic test strips G01N33/54387

Abstract

A wicking material is disclosed that exhibits a horizontal wicking velocity of at least about 1.0 millimeter per second when contacted with a physiological fluid such as blood, lymph or cellular interstitial fluid. This high wicking rate is achieved by means of treatment of a fibrous wicking material candidate with a low temperature gas plasma, particularly a glow discharge gas plasma formed in a gaseous blend made up predominantly of a mixture of oxygen with a saturated alkane chosen from the group consisting of methane, ethane and propane. Diagnostic test strips made with the surface-modified wicking material, and containing an immobilized reagent means for analysis of an analyte in a physiological fluid, show improved performance in terms of increased accuracy, finer precision of analyses, reduced time of analysis, a smaller fluid sample size requirement, and improved compliance with manufacturing standards resulting in lower manufacturing costs blood sugar determinations.

Claims

1. The method of analyzing an analyte in a physiological fluid comprising contacting with a wick with a sample of physiological fluid, and delivering a portion of the sample to an immobilized reagent means by wicking through the wick, wherein the wick comprises a fibrous wicking material in the form of a sheet or cloth that is surface-modified by exposure to a glow discharge gas plasma so as to exhibit a horizontal wicking rate of at least about 1.0 millimeter per second in contact with the physiological fluid.

2. The method according to claim 1 wherein the glow discharge gas plasma is formed in a gaseous blend composed predominantly of a mixture of oxygen with a saturated alkane chosen from the group consisting of methane, ethane and propane.

3. The method according to claim 2 wherein the fibrous wicking material consists of a woven cotton-polyester fabric.

4. The method according to claim 3 wherein the fibrous wicking material exhibits a horizontal wicking rate of at least about 2.0 millimeters per second in contact with a physiological fluid.

5. The method according to claim 2 wherein the fibrous wicking material consists of a fabric devoid of cotton.

6. The method of claim 1 wherein the glow discharge gas plasma comprises three-fifths oxygen.

7. A diagnostic test strip suitable for analysis of an analyte in a physiological fluid comprising an immobilized reagent means for detection and measurement of the analyte, a fibrous wicking material in the form of a sheet or cloth having a portion thereof in contact with the immobilized reagent means, and a holder for said reagent means and wicking material, wherein the wicking material has been surface-modified by exposure to a glow discharge gas plasma and exhibits a horizontal wicking rate of at least about 1.0 millimeter per second toward a physiological fluid, wherein also a portion of a sample of physiological fluid placed on said wicking material at a site apart from said reagent means is conveyed by wicking to said reagent means for analysis.

8. The diagnostic test strip according to claim 7 wherein the glow discharge gas plasma is formed in a gaseous blend composed predominantly of a mixture of oxygen with a saturated alkane chosen from the group consisting of methane, ethane and propane.

9. The diagnostic test strip according to claim 8 wherein the fibrous wicking material consists of a woven cotton-polyester fabric.

10. The diagnostic test strip according to claim 9 wherein the woven cotton-polyester fabric exhibits a horizontal wicking rate of at least about 2.0 millimeters per second toward a physiological fluid.

11. The diagnostic test strip according to claim 8 wherein the fibrous wicking material consists of a fabric devoid of cotton.

12. The diagnostic test strip according to claim 7 wherein the glow discharge gas plasma comprises three-fifths oxygen.

13. The diagnostic test strip according to claim 8 wherein said combination of oxygen and alkane produces a thin and tightly crosslinked veneer on the surface of the wicking material for maximum wicking.

14. A wick comprising a fibrous wicking material in the form of a sheet or cloth which has been surface-modified by exposure to a glow discharge gas plasma so as to exhibit a horizontal wicking rate of at least about 1.0 millimeter per second in contact with a physiological fluid.

15. The wick according to claim 14 wherein the glow discharge gas plasma is formed in a gaseous blend compose predominantly of a mixture of oxygen with a saturated alkane chosen from the group consisting of methane, ethane and propane.

16. The wick according to claim 15 wherein the fibrous wicking material consists of a woven cotton-polyester fabric.

17. The wick according to claim 16 wherein the fibrous wicking material exhibits a horizontal wicking rate of at least about 2.0 millimeters per second in contact with a physiological fluid.

18. The wick according to claim 15 wherein the fibrous wicking material consists of a fabric devoid of cotton.

19. The wick according to claim 14 wherein said glow discharge gas plasma comprises three-fifths oxygen.

20. The wick according to claim 15 wherein said combination of oxygen and alkane produces a thin and tightly crosslinked veneer on the surface of the wicking material for maximum wicking.