Capillary flow control in a medical diagnostic device

• US 6,488,827 B1
• Filed: 03/31/2000
• Issued: 12/03/2002
• Est. Priority Date: 03/31/2000
• Status: Expired due to Term

• Current Assignee: Cilag Gmbh International (Johnson & Johnson)
• Original Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Inventors: Shartle, Robert Justice
• Primary Examiner(s): Warden, Sr., Robert J.
• Assistant Examiner(s): Olsen, Kaj K.
• Application Number:
  US09/541,132
• Time in Patent Office: 977 Days
• Field of Search: 204/403, 204/409, 204/400, 422/81, 422/82, 422/100, 422/102, 422/61, 422/82.01
• US Class Current: 204/403.01
• CPC Class Codes: B01L 2200/027 for microfluidic devices
• CPC Class Codes: B01L 2300/0645 Electrodes
• CPC Class Codes: B01L 2300/0825 Test strips
• CPC Class Codes: B01L 2300/0887 Laminated structure
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 2400/0688 surface tension valves, capillary stop, capillary break
• CPC Class Codes: B01L 3/502707 characterised by the manufacture of the container or its components by shaping or joining plastic parts B29C59/00, B29C65/00; by laminating B32B37/00; manufacture of microstructural devices in general B81C
• 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
• CPC Class Codes: B01L 3/502738 characterised by integrated valves microvalves F16K99/0001

Abstract

A medical diagnostic device for measuring an analyte concentration in a sample of a biological fluid includes a capillary flow channel in the device to convey the sample from an inlet to a second region. The flow channel has a capillary dimension in at least one direction. A stop junction in the flow channel has a boundary region that has a dimension that is greater in that direction and forms an angle that points toward the sample inlet.

Claims

1. A medical diagnostic device for measuring an analyte concentration of a biological fluid, comprising a capillary flow channel within the device, in fluid communication with a sample inlet, the flow channel

a) adapted for conveying a sample of the biological fluid in a first direction, from a first region, proximate to the sample inlet, to a second region, distal to the sample inlet, the first region having a capillary dimension in a second direction, substantially perpendicular to the first direction;

and

b) having a stop junction, comprising a boundary region that

i) separates the first and second regions,

ii) has a predetermined dimension in the second direction that is greater than the capillary dimension, and

iii) forms an angle that points toward the first region.

2. The device of claim 1, further comprising, in the second region, a measurement area, in which is measured a physical parameter of the sample that is related to the analyte concentration of the fluid.

3. The device of claim 2, in which the device comprises a first layer and a second layer, separated in the second direction by an intermediate layer, in which a cutout in the intermediate layer forms, with the first and second layers, the sample inlet, measurement area, and flow channel.

4. The device of claim 3, in which the second region has a dimension in the second direction that is substantially the same as the capillary dimension.

5. The device of claim 4, in which the boundary region comprises a pattern scored into the surface of the first layer.

6. The device of claim 3, in which the biological fluid is electrically conductive, the first and second layers each have a conductive surface adjoining the intermediate layer, which is an insulating layer, and the flow channel further comprises

a) a dry reagent on the conductive surface of one of the layers for reacting with the sample to yield a change in an electrical parameter that can be related to the analyte concentration of the fluid; and

b) an electrochemical cell, within which the electrical parameter is measured, and the stop junction comprises an insulating pattern scored into the conductive surface of one of the layers, whereby sample that flows across the pattern provides a conductive path from the first region to the second region.

7. The device of claim 6, further comprising a second sample inlet, for introducing sample to a third region of the device, the third region being in fluid communication with the second region, whereby fluid introduced into the first sample inlet travels in a substantially opposite direction to fluid introduced into the second sample inlet.

8. The device of claim 7, in which the boundary region forms a serrated pattern, having angles pointing toward both sample inlets.

9. The device of claim 1, further comprising a second sample inlet, for introducing sample to a third region of the device, the third region being in fluid communication with the second region, whereby fluid introduced into the first sample inlet travels in a substantially opposite direction to fluid introduced into the second sample inlet.

10. The device of claim 9, in which the boundary region forms a serrated pattern, having angles pointing toward both sample inlets.