Test element, system, and method of controlling the wetting of same

• US 7,842,235 B2
• Filed: 02/14/2005
• Issued: 11/30/2010
• Est. Priority Date: 02/14/2004
• Status: Expired due to Fees

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Inventors: Fiedler, Wolfgang, Kraemer, Peter, Ocvirk, Gregor
• Primary Examiner(s): Griffin; Walter D
• Assistant Examiner(s): Mui; Christine T
• Application Number:
  US11/057,524
• Publication Number:
  US 20050254997A1
• Time in Patent Office: 2,115 Days
• Field of Search: 422/57, 429/38, 204/450, 204/451, 204/454, 204/547
• US Class Current: 422/425
• CPC Class Codes: B01L 2300/0809 rectangular shaped
• CPC Class Codes: B01L 2300/0825 Test strips
• CPC Class Codes: B01L 2300/0877 Flow chambers
• CPC Class Codes: B01L 2300/0887 Laminated structure
• CPC Class Codes: B01L 2300/123 Flexible; Elastomeric
• CPC Class Codes: B01L 2300/161 Control and use of surface tension forces, e.g. hydrophobic, hydrophilic
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 2400/0415 electrical forces, e.g. electrokinetic
• CPC Class Codes: B01L 3/50273 characterised by the means or forces applied to move the fluids micropumps F04B19/006, of the membrane type F04B43/043

Abstract

The invention relates to a test element for the testing of a liquid sample. The test element includes a sample application area, a test field, a sample transport path extending between the sample application area and the test field and an actuator field including an electrically-conductive layer. The actuator field is switchable between a first state attracting the sample and a second state attracting the sample less by applying to the conductive layer an electric voltage that is different from an earth potential. The actuator field has a section that is arranged at about the same distance from the sample application area as the test field, measured along the sample transport path. Such that, a wetting of the test field by the sample can be controlled by applying a voltage to the actuator field.

Claims

1. Test element for the testing of a liquid sample, the test element comprising:

a sample application area having an exposed surface on which a liquid sample can be applied;

a test field at which a measuring parameter that is characteristic of the test is measured, the test field comprising a reagent which reacts with a medically significant analyte present in the liquid sample to produce the measuring parameter, wherein the measuring parameter that is characteristic of the analysis can be measured with a measuring facility and can be analyzed by an analytical device to achieve a result of a test performed with the test element;

a sample transport path extending between the sample application area and the test field; and

an actuator field assigned to the test field and including an electrically-conductive layer, the actuator field being switchable between a first state attracting the sample and a second state attracting the sample less than in the first state, the actuator field being switchable by applying an electric voltage that is different from an earth potential to the conductive layer, and

wherein the actuator field comprises a section that is disposed along the sample transport path intermediate the sample application area and the test field, the section being arranged at about the same distance from the sample application area as the test field, measured along the sample transport path, such that by applying a voltage to the actuator field, a wetting of the test field which includes a spreading of the sample over the test field can be controlled.

2. The test element of claim 1, wherein the actuator field includes a second section that covers the test field.

3. The test element of claim 2, wherein the second section of the actuator field is permeable with regard to the sample.

4. The test element of claim 2, wherein the second section of the actuator field comprises orifices.

5. The test element claim 2, wherein the second section of the actuator field comprises pores.

6. The test element of claim 1, wherein the actuator field extends from the test field to the sample application area.

7. The test element of claim 1, wherein the sample application area is connected to the test field by a transport zone.

8. The test element of claim 7, comprising actuator fields.

9. The test element of claim 8, wherein the transport zone can be filled independently of a wetting of the test field by a sample applied to the sample application area by switching one of the actuator fields.

10. The test element of claim 8, wherein at least one of the actuator fields facilitates a spreading of the sample present on the sample application area.

11. The test element of claim 8, wherein the actuator fields extend next to each other in longitudinal direction along a transport direction of the sample.

12. The test element of claim 1, wherein the actuator field has a hydrophilic surface in the first state.

13. The test element of any claim 1, wherein the actuator field has a hydrophobic surface in the second state.

14. The test element of claim 1, wherein the level of the electric voltage can control a strength of an attracting force that can be exerted on the sample by the actuator field applied.

15. The test element of claim 14, wherein the level of the electric voltage can control a rate at which the sample migrates from the sample application area to the test field applied to the actuator field.

16. The test element of claim 1, wherein the sample application area is connected to the test field by a transport zone and the transport zone includes a channel.

17. The test element of claim 16, wherein the channel has a width of about 5 μ

m to about 2 mm.

18. The test element of claim 16, wherein the channel has a height of about 50μ

m to about 500 μ

m.

19. The test element of claim 16, wherein the channel has a cross-sectional area of about 50 μ

m to about 10⁶ μ

m.

20. The test element of claim 16, comprising actuator fields and at least one of the actuator fields is arranged at an upper wall and at a lower wall of the channel.

21. The test element of claim 16, wherein a cover film forms an upper wall of the channel.

22. The test element of claim 16, comprising actuator fields, wherein actuator fields are arranged on the upper wall and on the lower wall of the channel, and the actuator fields on the upper and lower walls are arranged in pairs and opposite to each other.

23. The test element of claim 1, wherein the actuator field is arranged on a cover film.

24. The test element of claim 23, wherein the cover film is a hydrophobic material.

25. The test element of claim 23, wherein the cover film is a hydrophobic material.

26. The test element of claim 1, wherein the actuator field comprises a cover layer covering the electrically conductive layer.

27. The test element of claim 26, wherein the cover layer is a hydrophobic material.

28. The test element of claim 26, wherein the cover layer comprises a substance that can be released by applying an electric voltage to the actuator field.

29. The test element of claim 28, wherein the substance is a detergent.

30. The test element of claim 1, wherein the sample application area is connected to the test field by a transport zone, the transport zone includes a channel, and the channel extends beyond the test field.

31. The test element of claim 30, comprising actuator fields and at least one actuator field is arranged in the channel downstream from the test field.

32. The test element of claim 31, wherein at least one actuator field is arranged downstream from the test field and has a larger width than at least one actuator field arranged in the channel upstream from the test field.

33. The test element of claim 31, wherein the actuator field is positioned to de-wet the sample application area of the sample upon switching the actuator field positioned at the sample application area.

34. The test element of claim 1, wherein the actuator field is positioned to remove the sample from the test field upon switching the actuator field.

35. The test element of claim 1, comprising a sample removal area formed to receive the sample after completion of a test.

36. The test element of claim 1, wherein the sample application area comprises two contact sites allowing the conductivity to be measured between the two contact sites.

37. The test element of claim 1, wherein two test fields are present, to which a partial volume each of the sample can be guided simultaneously by actuating actuator fields such that the two test fields can be wetted at about the same point in time and a measurement can be initiated on both test fields at about the same point in time.

45. The test element of claim 1, wherein the reagent is configured to be maintained dry before contact with the liquid sample having the medically significant analyte.

38. A test element analysis system for the testing of a liquid sample, comprising:

a test element including a sample application area having an exposed surface on which a liquid sample can be applied, a test field at which a measuring parameter that is characteristic of the test is measured and comprising a reagent which reacts with a medically significant analyte present in the liquid sample to produce the measuring parameter, wherein the measuring parameter that is characteristic of the analysis can be measured with a measuring facility and can be analyzed by an analytical device to achieve a result of a test performed with the test element, a sample transport path extending between the sample application area and the test field, and an actuator field assigned to the test field and including an electrically-conductive layer, the actuator field being switchable between a first state attracting the sample and a second state attracting the sample less than in the first state, the actuator field being switchable by applying an electric voltage that is different from an earth potential to the conductive layer, and wherein the actuator field comprises a section that is disposed along the sample transport path intermediate the sample application area and the test field, the section being arranged at about the same distance from the sample application area as the test field, measured along the sample transport path such that a wetting of the test field which includes a spreading of the sample over the test field can be controlled by applying a voltage to the actuator field; and

an analytical device with a measuring facility, by which a measuring parameter that is characteristic of a test can be measured at the test element.

39. The system of claim 38 comprising test elements.

46. The test element of claim 38, wherein the reagent is configured to be maintained dry before contact with the liquid sample having the medically significant analyte.

40. A method for controlling the wetting of a test element, the method comprising the steps of:

providing the test element, wherein the test element includes a sample application area having an exposed surface, a test field, a sample transport path extending between the sample application area and the test field, and an actuator field assigned to the test field and including an electrically-conductive layer, the actuator field being switchable between a first state attracting the sample and a second state attracting the sample less than in the first state, the actuator field being switchable by applying an electric voltage that is different from an earth potential to the conductive layer, and wherein the actuator field comprises a section that is disposed along the sample transport path intermediate the sample application area and the test field, the section being arranged at about the same distance from the sample application area as the test field, measured along the sample transport path;

applying a liquid sample to the exposed surface of the sample application area;

switching the actuator field from the first state to the second state, thereby controlling the wetting of the test field, which wetting includes a spreading of the sample over the test field; and

reacting a reagent of the test field with an analyte present in the liquid sample and measuring a measuring parameter at the test field that is characteristic of the test, wherein the measuring parameter that is characteristic of the analysis can be measured with a measuring facility and can be analyzed by an analytical device to achieve a result of a test performed with the test element.

41. The method of claim 40, wherein consecutive samples are applied to the sample application area.

42. The method of claim 40, wherein the switching of the actuator field guides the consecutive samples to the test field.

43. The method of claim 40, wherein the switching of the actuator field combines the consecutive samples without the formation of bubbles.

44. The method of claim 40, wherein the reagent is dry before contact by the liquid sample.