Test strip with slot vent opening

• US 20050013731A1
• Filed: 06/18/2004
• Published: 01/20/2005
• Est. Priority Date: 06/20/2003
• Status: Active Grant

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Roche Operations Limited (Roche Holding AG)
• Inventors: Burke, David W., Marquant, Michael
• Granted Patent: US 7,829,023 B2
• Time in Patent Office: Days
• US Class Current: 422/56
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001
• CPC Class Codes: G01N 33/558 using diffusion or migration of antigen or antibody immunochromatographic test strips G01N33/54387
• CPC Class Codes: Y10T 156/1059 Splitting sheet lamina in plane intermediate of faces
• CPC Class Codes: Y10T 156/1084 of continuous or running length bonded web

Abstract

A test strip with a covering layer having a novel slot. The slot divides the inventive covering layer into two parts and provides a vent opening that allows air to escape as fluid enters a cavity or sample receiving chamber formed in the test strip. In preferred embodiments, the covering layer is clear such that the user can see through it and the slot doubles as a “fill line.” The user can thus watch the fluid sample enter the test strip, progress through the capillary cavity, and then stop at the slot or fill-line. This provides positive assurance to the user that the sample size is sufficient and the test strip has been filled properly. The present invention also provides an advantageous method of mass-producing the inventive test strips without having to align the slot or vent opening laterally with respect to the test strips and without having to punch a vent opening. The method is also well suited to mass production by roll processing techniques.

Claims

1. A test strip, comprising:

a base substrate having a reagent layer disposed thereon;

a covering layer overlying the base substrate and comprising a chamber cover and a body cover having a slot therebetween, the slot being positioned over the reagent layer; and

a sample receiving chamber disposed between the base substrate and the covering layer, the slot being in communication with the sample receiving chamber and defining a vent opening in the covering layer that allows air to escape as fluid enters the sample receiving chamber.

2. The test strip of claim 1, wherein the slot comprises a gap which spaces the body cover from the chamber cover.

3. The test strip of claim 2, wherein the gap extends across the width of the covering layer.

4. The test strip of claim 1, wherein the covering layer is unitary and the slot comprises a recess formed on the underside thereof, the recess extending to a side of the test strip and terminating at the vent opening.

5. The test strip of claim 4, wherein the recess extends across the width of the test strip and the vent opening comprises two vent openings disposed on opposite sides of the test strip.

6. The test strip of claim 1, wherein the slot is substantially straight.

7. The test strip of claim 6, wherein the slot comprises a fill line.

8. The test strip of claim 6, wherein the slot is oriented substantially perpendicular to a longitudinal axis of the test strip.

9. The test strip of claim 1, wherein the chamber cover and the body cover are disposed in substantially the same horizontal plane.

10. The test strip of claim 9, wherein the chamber cover and the body cover are positioned end to end in a lengthwise direction along the test strip.

11. The test strip of claim 1, further comprising an electrode disposed in the sample receiving chamber, the electrode being covered by the reagent layer.

12. The test strip of claim 1, wherein the chamber cover overlies the sample-receiving chamber.

13. The test strip of claim 12, wherein the slot comprises a hydrophobic side adjacent the body cover, further wherein sample fluid entering the sample receiving chamber will progress to the slot but no farther, whereby the slot comprises a fill line.

14. The test strip of claim 13, wherein the chamber cover is transparent or translucent, whereby progression of sample fluid into the sample receiving chamber to the fill line is visible.

15. The test strip of claim 13, wherein the chamber cover comprises a hydrophilic surface on an underside thereof, whereby wicking into the sample-receiving chamber to the slot is promoted.

16. The test strip of claim 13, wherein the slot comprises a gap that spaces the chamber cover from the body cover.

17. The test strip of claim 1, wherein the body cover is adhered to the test strip with a hydrophobic adhesive.

18. The test strip of claim 1, wherein the underside of the chamber cover is hydrophilic.

19. The test strip of claim 18, wherein the underside of the chamber cover is coated with a hydrophilic substance.

20. The test strip of claim 1, wherein the chamber cover and body cover are formed from the same material.

21. The test strip of claim 1, further comprising:

electrodes disposed in the sample receiving chamber;

contact pads formed on the base substrate at a meter insertion end of the test strip; and

electrode traces extending along the base substrate and connecting the electrodes to the contact pads, the covering layer covering the electrode traces and exposing the contact pads.

22. The test strip of claim 1, further comprising a working electrode and a counter electrode disposed within the sample receiving chamber, the slot being positioned downstream of the working and counter electrodes.

23. The test strip of claim 1, wherein the chamber cover overlies the sample receiving chamber and the chamber cover is transparent or translucent.

24. The test strip of claim 1, wherein the slot is substantially aligned with an interior end of the sample receiving chamber.

25. The test strip of claim 1, further comprising a spacing layer disposed between the covering layer and the base substrate, the spacing layer defining a void portion that further defines the height and perimeter of the sample receiving chamber between the base and the covering layer.

26. The test strip of claim 25, wherein the void portion forms a channel that begins at an opening at an edge of the test strip, the opening being in communication with the sample receiving chamber.

27. The test strip of claim 26, wherein the void portion terminates at a position substantially aligned with the slot.

28. A test strip, comprising:

a base substrate having electrodes formed thereon;

a covering layer overlying the base substrate, the covering layer comprising a chamber cover and a body cover having a slot therebetween; and

a unitary spacing layer disposed between the covering layer and the base substrate, the spacing layer having a void that defines a sample receiving chamber between the base substrate and the covering layer;

wherein the slot is in communication with the sample receiving chamber, thereby defining a vent opening in the covering layer that allows air to escape as fluid enters the sample receiving chamber.

29. The test strip of claim 28, wherein the slot is substantially aligned with an interior end of the sample receiving chamber.

30. The test strip of claim 28, wherein one surface of the spacing layer is adhered to the base substrate and an opposite surface of the spacing layer is adhered to the covering layer.

31. The test strip of claim 28, wherein the chamber cover comprises a hydrophilic surface adjacent the sample receiving chamber.

32. The test strip of claim 28, further comprising a reagent layer disposed in the sample receiving chamber covering at least one of the electrodes.

33. The test strip of claim 32, wherein the reagent layer extends under the spacing layer and is sandwiched between the spacing layer and the base substrate.

34. The test strip of claim 33, wherein the reagent layer extends across the width of the test strip.

35. The test strip of claim 32, wherein the reagent layer substantially covers the bottom of the sample receiving chamber.

36. The test strip of claim 32, wherein the slot is positioned over the reagent layer.

37. The test strip of claim 28, wherein the sample receiving chamber is bounded on the top side thereof by the chamber cover and the underside of the chamber cover is hydrophilic, whereby wicking of sample fluid into the sample receiving chamber is promoted.

38. The test strip of claim 28, wherein the slot comprises a gap that extends across the covering layer and separates the body cover from the chamber cover, the body cover and the chamber cover having substantially straight edges proximate the gap.

39. The test strip of claim 38, wherein the gap is oriented substantially perpendicular to a longitudinal axis of the test strip.

40. The test strip of claim 28, wherein the sample receiving chamber communicates with a fluid receiving opening disposed at an edge of the test strip.

41. The test strip of claim 28, wherein the body cover includes a hydrophobic portion adjacent the slot.

42. The test strip of claim 28, wherein the body cover is adhered to the spacing layer with a hydrophobic adhesive.

43. The test strip of claim 28, wherein the body cover and chamber cover are formed from the same material.

44. The test strip of claim 43, wherein the body cover is treated with a hydrophobic substance and the chamber cover is treated with a hydrophilic substance.

45. The test strip of claim 28, further comprising electrode traces extending from the electrodes along the base substrate and terminating in contact pads at a meter insertion end of the test strip, the contact pads being exposed for electrical connection thereto.

46. The test strip of claim 28, wherein the chamber cover overlies substantially the entire length of the sample receiving chamber.

47. The test strip of claim 46, wherein the chamber cover is transparent or translucent above the sample receiving chamber, whereby fluid entering the sample receiving chamber is visible through the chamber cover.

48. The test strip of claim 47, wherein a top surface of the spacing layer adjacent the void and the bottom of the sample receiving chamber have contrasting colors and are visible through the chamber cover.

49. The test strip of claim 28, wherein the base substrate, spacing layer and covering layer are adhered to one another by one of heat welding, laser welding, heat sensitive adhesives, pressure sensitive adhesives and combinations thereof.

50. The test strip of claim 28, wherein the electrodes are disposed in the sample receiving chamber.

51. The test strip of claim 50, further comprising contact pads disposed at a meter insertion end of the test strip and electrode traces extending along the base substrate connecting the electrodes to the contact pads.

52. The test strip of claim 51, wherein the covering layer and spacing layer are sized to expose the contact pads, whereby the contact pads can be electrically connected to a meter.

53. The test strip of claim 52, wherein the chamber cover overlies substantially the entire length of the sample receiving chamber and has about the same length as the sample receiving chamber.

54. The test strip of claim 53, wherein the chamber cover is transparent or translucent.

55. The test strip of claim 28, wherein the body cover and chamber cover are aligned end to end and are disposed in substantially the same horizontal plane.

56. A method of manufacturing a plurality of test strips, said method comprising:

(a) providing a web of base substrate material;

(b) forming a plurality of electrode sets on the web;

(c) providing a reagent layer covering at least one electrode of each electrode set;

then

(d) providing a continuous web of spacing material having a series of cavities formed therein and laminating the web of spacing material over the web of base substrate material such that each one of the cavities aligns with a respective one of the electrode sets;

(e) providing a web of covering layer made from two pieces and laminating it over the web of spacing material such that the two pieces are separated by a gap and the gap is positioned over the series of cavities; and

(f) cutting the web into the plurality of test strips.

57. The method of claim 56, wherein the reagent layer is applied in a uniform thickness as continuous stripe along the web of base substrate material.

58. The method of claim 57, wherein step (c) further comprises depositing the reagent stripe over the plurality of electrode sets.

59. The method of claim 56, wherein step (b) comprises applying a conductive coating to the web of base substrate and then removing portions of the conductive coating to form the electrode sets.

60. The method of claim 59, wherein the portions of the conductive coating are removed by laser ablation.

61. The method of claim 60, wherein the laser ablation comprises broad field laser ablation.

62. The method of claim 56, wherein the two pieces have substantially straight edges, whereby the gap is substantially straight and extends over the series of cavities.

63. The method of claim 56, wherein each of the two pieces of covering material comprises an elongated continuous web.

64. The method of claim 63, further comprising making a series of substantially equidistant cuts between the electrode sets, the cuts being substantially perpendicular to the gap, whereby each individual test strip formed thereby has a gap extending across its covering layer, the individual gaps forming vent openings communicating with respective cavities.

65. The method of claim 64, wherein the cutting further comprises cutting one end of the web to form fluid receiving ends of the test strips with openings at their edges, each opening leading into a respective cavity.

66. The method of claim 65, wherein the fluid receiving ends are Y-shaped.

67. The method of claim 65, wherein the cavities extend from the openings at the edges of the test strips to the vent openings formed in the covering layers.

68. The method of claim 56, further comprising positioning the gap over an interior end of the series of cavities.

69. The method of claim 56, further comprising applying the two pieces to the web at substantially the same time.

70. The method of claim 56, further comprising providing one piece of the covering layer web with a hydrophilic surface and the other piece of covering layer web with a hydrophobic surface.

71. A test strip, comprising:

a test strip body;

a sample receiving chamber disposed in the test strip body;

a fluid receiving opening disposed at an edge of the test strip body and communicating with the sample receiving chamber;

a covering layer at least partially defining the top of the test strip body, the covering layer comprising two pieces having a slot therebetween, the slot forming a vent opening positioned over and in communication with the sample receiving chamber, whereby air can escape through the vent opening as fluid enters the sample receiving chamber; and

the slot comprising a hydrophobic edge, wherein sample fluid can progress into the sample-receiving chamber to the slot, but no farther, whereby the slot comprises a fill line.

72. The test strip of claim 71, further comprising a reagent layer and at least one electrode disposed in the sample receiving chamber.

73. The test strip of claim 72, wherein the slot is positioned over the reagent layer.

74. The test strip of claim 71, further comprising a base substrate defining the bottom of the test strip body, the base substrate having electrodes formed thereon.

75. The test strip of claim 74, further comprising a reagent layer covering at least one of the electrodes, the at least one electrode being located within the sample receiving chamber.

76. The test strip of claim 71, wherein the test strip body further comprises:

a base substrate layer defining the bottom of the test strip and having electrodes formed thereon;

a spacing layer disposed between the covering layer and the base substrate layer; and

the spacing layer having a void that partially defines the boundaries of the sample receiving chamber, the void originating at the fluid receiving opening and terminating at a location substantially aligned with the slot.

77. The test strip of claim 71, wherein the sample receiving chamber extends inwardly from the fluid receiving opening and terminates at a location substantially aligned with the slot.

78. The test strip of claim 77, wherein a first of the two pieces of the covering layer overlies the sample receiving chamber, the first piece having an end thereof substantially aligned with the fluid receiving opening.

79. The test strip of claim 78, wherein the test strip body has an elongate shape and the sample receiving chamber extends lengthwise with respect to the test strip body, the fluid receiving opening being disposed at an end of the test strip body.

80. The test strip of claim 71, wherein the two pieces of the covering layer are formed of the same material, one of the pieces being treated with a hydrophobic substance and the other being treated with a hydrophilic substance.

81. The test strip of claim 80, wherein the piece of the covering layer treated with the hydrophilic substance overlies the sample receiving chamber.

82. The test strip of claim 71, further comprising a hydrophilic surface in the sample receiving chamber to promote wicking of the sample into the sample receiving chamber.

83. The test strip of claim 82, wherein the hydrophilic surface comprises the bottom of the first piece of the covering layer.

84. The test strip of claim 71, wherein the two pieces of the covering layer are disposed end to end in a lengthwise direction along the test strip.

85. The test strip of claim 84, wherein the two pieces of the covering layer are disposed in substantially the same plane.

86. A method of testing a fluid sample for the presence or concentration of an analyte, comprising:

(a) providing a test strip having a sample-receiving opening at an edge thereof, the sample-receiving opening leading into a sample-receiving chamber that extends into the test strip;

(b) providing a covering layer for the test strip formed with a slot that overlies the sample receiving chamber;

(c) placing a fluid sample at the sample receiving opening;

(d) drawing the sample into the sample receiving chamber by capillary action while at the same time displacing air from the sample receiving chamber through the slot;

(e) continuing to draw the sample into the sample receiving chamber until the sample reaches the slot and then halting further progress of the sample beyond the slot, whereby the slot comprises a fill line; and

(f) determining the presence or concentration of the analyte.

87. The method of claim 86, wherein the covering layer has a transparent or translucent portion that overlies the sample receiving chamber such that the sample receiving chamber is visible through the covering layer, the method further comprising observing the progression of the sample from the sample-receiving opening to the slot.

88. The method of claim 86, wherein the halting of further progress of the sample beyond the slot comprises providing the slot with a hydrophobic edge.

89. The method of claim 86, further comprising providing a reagent layer in the sample receiving chamber and positioning the slot over the reagent layer.

90. The method of claim 86, wherein the slot comprises a gap, wherein at least a portion of the air displaced exits from the top of the test strip.

91. The method of claim 86, wherein the chamber cover and body cover are disposed in substantially the same plane.

92. The method of claim 91, wherein the chamber cover and body cover are arranged end to end.

93. A method of testing a fluid sample for the presence or concentration of an analyte, comprising:

(a) providing a test strip having a sample-receiving opening at an edge thereof, the sample-receiving opening leading into a sample-receiving chamber that extends inwardly on the test strip;

(b) providing a covering layer for the test strip comprising a chamber cover and a body cover with a gap therebetween, the gap overlying a portion of the sample receiving chamber;

(c) placing a fluid sample at the sample receiving opening;

(d) drawing the sample into the sample receiving chamber by capillary action while at the same time displacing air from the sample receiving chamber through the gap, wherein at least a portion of the air displaced exits from the top of the test strip; and

(e) determining the presence or concentration of the analyte.

94. The test strip of claim 93, wherein step (d) further comprises drawing the sample into the sample receiving chamber until the sample reaches the gap and then halting further progress of the sample beyond the gap, wherein the gap comprises a fill line.

95. The method of claim 94, wherein the covering layer has a transparent or translucent portion that overlies the sample receiving chamber such that the sample receiving chamber is visible through the covering layer, the method further comprising observing the progression of the sample from the sample-receiving opening to the gap.

96. The method of claim 93, wherein the chamber cover and body cover are disposed in substantially the same plane.

97. The method of claim 96, wherein the chamber cover and body cover are arranged end to end.

98. A test strip, comprising:

a base substrate having a reagent layer disposed thereon;

a covering layer overlying the base substrate and comprising a chamber cover and a body cover having a slot therebetween, the slot being formed as one of a notch on the underside of the covering layer and an overlap between the covering layer and the chamber cover; and

a sample receiving chamber disposed between the base substrate and the covering layer, the slot being in communication with the sample receiving chamber and defining a vent opening in the covering layer that allows air to escape as fluid enters the sample receiving chamber.

99. The test strip of claim 98, wherein the slot is positioned over the reagent layer.

100. The test strip of claim 98, wherein the slot extends across the width of the covering layer.

101. The test strip of claim 98, wherein the covering layer is unitary and the slot comprises the notch.

102. The test strip of claim 98, wherein the slot comprises the overlap between the chamber cover and the body cover.

103. The test strip of claim 102, wherein the overlap comprises the chamber cover covering an edge of the body cover.

104. The test strip of claim 102, wherein the slot extends across the width of the test strip and the vent opening comprises two vent openings disposed on opposite sides of the test strip.

105. The test strip of claim 98, wherein the slot is substantially straight.

106. The test strip of claim 105, wherein the slot comprises a fill line.

107. The test strip of claim 98, wherein the slot is oriented substantially perpendicular to a longitudinal axis of the test strip.

108. A test strip, comprising:

a base substrate having a reagent layer disposed thereon;

a covering layer overlying the base substrate and comprising a chamber cover and a body cover having a slot therebetween, the body cover being thicker than the chamber cover; and

a sample receiving chamber disposed between the base substrate and the covering layer, the slot being in communication with the sample receiving chamber and defining a vent opening in the covering layer that allows air to escape as fluid enters the sample receiving chamber.

109. The test strip of claim 108, wherein the slot comprises a gap which spaces the body cover from the chamber cover.

110. The test strip of claim 109, wherein the gap extends across the width of the covering layer.

111. The test strip of claim 108, wherein the slot is substantially straight.

112. The test strip of claim 111, wherein the slot comprises a fill line.

113. The test strip of claim 111, wherein the slot is oriented substantially perpendicular to a longitudinal axis of the test strip.

114. The test strip of claim 108, wherein the chamber cover and the body cover are disposed in substantially the same horizontal plane.

115. The test strip of claim 114, wherein the chamber cover and the body cover are positioned end to end in a lengthwise direction along the test strip.

116. The test strip of claim 108, wherein the chamber cover overlies the sample receiving chamber.

117. The test strip of claim 116, wherein the slot comprises a hydrophobic side adjacent the body cover, further wherein sample fluid entering the sample receiving chamber will progress to the slot but no farther, whereby the slot comprises a fill line.

118. The test strip of claim 116, wherein the chamber cover is transparent or translucent, whereby progression of sample fluid into the sample receiving chamber to the fill line is visible.

119. The test strip of claim 117, wherein the chamber cover comprises a hydrophilic surface on an underside thereof, whereby wicking into the sample-receiving chamber to the slot is promoted.

120. The test strip of claim 117, wherein the slot comprises a gap that spaces the chamber cover from the body cover.

121. The test strip of claim 108, wherein the chamber cover and body cover are formed from the same material.

122. A method of manufacturing test strips, said method comprising:

(a) providing a first web of material having a series of spaced cavities formed therein, the cavities defining walls and a floor of a sample receiving chamber and the cavities being open on their tops;

(b) covering the first web of material with a second web of material, the second web having a first portion having a first thickness and a second portion having a second thickness greater than the first thickness, wherein the first portion is aligned over and covers the cavities; and

(c) cutting the structure produced in step (b) into the test strips.

123. The method of claim 122, further comprising laminating the second web over the first web such that the first portion and the second portion are separated by a gap.

124. The method of claim 123, further comprising positioning the gap over the series of cavities.

125. The method of claim 123, wherein the first portion and the second portion each have a substantially straight edge, whereby the gap is substantially straight and extends over the series of cavities.

126. The method of claim 122, further comprising forming a plurality of electrode sets on the first web of material.

127. The method of claim 126, further comprising aligning each one of the cavities with a respective one of the electrode sets.

128. The method of claim 126, further comprising providing a reagent layer covering at least one electrode of the electrode sets.

129. The method of claim 128, wherein the reagent layer is applied in a uniform thickness as a continuous stripe along the first web of material.

130. The method of claim 129, further comprising depositing the reagent stripe over the plurality of electrode sets.

131. The method of claim 122, wherein the second web comprises two layers of material that are separated by a gap that overlies the cavities.