Surface-modified wick for diagnostic test strip

• US 20020102739A1
• Filed: 12/02/2000
• Published: 08/01/2002
• Est. Priority Date: 12/02/2000
• Status: Active Grant

• Current Assignee: Queststar Medical, Inc.
• Original Assignee: Queststar Medical, Inc.
• Inventors: Nomura, Hiroshi, Petersen, Robert J., Hanson, August R., Kydd, Arthur R.
• Granted Patent: US 6,967,105 B2
• Time in Patent Office: Days
• 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. 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.

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

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

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

6. 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.

7. The diagnostic test strip according to claim 6 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.

8. The diagnostic test strip according to claim 7 wherein the fibrous wicking material consists of a woven cotton-polyester fabric.

9. The diagnostic test strip according to claim 8 wherein the woven cotton-polyester fabric exhibits a horizontal wicking rate of at least about 2.0 millimeters per second toward a physiological fluid.

10. The diagnostic test strip according to claim 7 wherein the fibrous wicking material consists of a fabric devoid of cotton.

11. A method of analyzing an analyte in a physiological fluid comprising contacting a wick with a sample of a 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.

12. The method according to claim 11 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.

13. The method according to claim 12 wherein the fibrous wicking material consists of a woven cotton-polyester fabric.

14. The method according to claim 13 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.

15. The method according to claim 12 wherein the fibrous wicking material consists of a fabric devoid of cotton.