Method of making a capillary channel

• US 20020079218A1
• Filed: 12/07/2001
• Published: 06/27/2002
• Est. Priority Date: 12/12/2000
• Status: Active Grant

• Current Assignee: Ascensia Diabetes Care Holdings AG (PHC Holdings Corporation)
• Original Assignee: Bayer Healthcare LLC (Bayer AG)
• Inventors: Brenneman, Allen J., Wogoman, Frank W.
• Granted Patent: US 6,911,130 B2
• Time in Patent Office: Days
• US Class Current: 204/400
• CPC Class Codes: B01L 2200/12 Specific details about manufacturing devices
• CPC Class Codes: B01L 2300/0645 Electrodes
• CPC Class Codes: B01L 2300/0809 rectangular shaped
• CPC Class Codes: B01L 2300/0825 Test strips
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• 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: B29C 2045/1477 Removable inserts, e.g. the insert being peeled off after moulding
• CPC Class Codes: B29C 45/14 incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles B29C45/1671 takes precedence
• CPC Class Codes: B29C 45/14065 Positioning or centering articles in the mould
• CPC Class Codes: B29C 45/14639 for obtaining an insulating effect, e.g. for electrical components
• CPC Class Codes: B29C 45/14754 being in movable or releasable engagement with the coating, e.g. bearing assemblies
• CPC Class Codes: G01N 2021/0346 Capillary cells; Microcells
• CPC Class Codes: G01N 21/03 Cuvette constructions
• CPC Class Codes: G01N 27/4473 by electric means

Abstract

An optical reagent format with a precise capillary channel is made by molding a format on a carrier of a precise predetermined thickness. The carrier includes an insert at least a portion of which is molded in the format. Once the format is made, the insert is detached from the carrier and removed from the format leaving a precisely dimensioned capillary channel with an inlet and vent. A reagent may be applied in the capillary channel and the format used to measure the analyte in a fluid such as blood.

An electrochemical sensor with a capillary channel is formed by placing a sacrificial insert and electrodes on a sensor base and applying plastic material. After the plastic material is cured, the sacrificial is removed leaving a capillary channel in the sensor. The inserts may be removed by a tool including a clamp for clamping and holding each insert stationary and a sliding block to which the sensor is secured.

Claims

1. A method of making an optical regent format with a capillary gap, comprising:

providing a carrier with an insert, said carrier and insert being of a predetermined thickness;

placing said carrier in a mold;

molding a format onto said carrier and insert;

separating said insert from said carrier; and

removing said insert from said format leaving a capillary gap in said format.

2. The method of making an optical reagent format claimed in claim 1 further comprising applying reagent in said capillary gap.

3. The method of making an optical reagent format claimed in claim 1 said capillary gap having open sides, and sealing said open sides of said capillary gap.

4. The method of making an optical reagent format claimed in claim 1 further comprising removing said format from said carrier.

5. The method of making an optical reagent format claimed in claim 1 providing a plurality of carriers joined together and each including an insert, and molding a format onto each of said plurality of carriers and inserts.

6. The method of making an optical reagent format claimed in claim 1 said format including a pair of legs, further comprising forming said capillary gap between a pair of legs of said format.

7. The method of making an optical reagent format claimed in claim 1 wherein molding said format comprises molding a first format on an upper surface of said carrier and molding a second format on a lower surface of said carrier.

8. The method of making an optical reagent format claimed in claim 7 wherein said first and second formats are of a conical configuration.

9. A method of making an optical reagent format with a capillary gap, comprising:

providing a carrier of a predetermined thickness;

providing an insert on said carrier;

molding a format onto said carrier and said insert with a portion of said insert extending out of said format; and

removing said insert from said format to provide a capillary channel with an inlet and a vent in said format formed by said insert.

10. The method of making an optical reagent format claimed in claim 9 comprising removing said carrier from said format.

11. The method of making an optical reagent format claimed in claim 9 said insert comprising a material of a melt temperature higher than the melt temperature of the material of said format.

12. The method of making an optical reagent format claimed in claim 9 comprising molding said format with a first leg for the application of a light source and a second leg for the application of a light detector, said capillary channel being between said first and second legs.

13. The method of making an optical reagent format claimed in claim 9 comprising molding said format with a first conical member on a first side of said format and a second conical member on a second side of said format with said capillary channel between said first conical member and said second conical member.

15. The method of molding an electrochemical sensor claimed in claim 14 wherein extracting said sacrificial insert includes clamping said insert and moving said sensor relative to said insert.

18. The tool claimed in claim 17 further comprising a base, said clamp including a second block secured to said base.

14. A method of molding an electrochemical sensor using a sacrificial insert, comprising:

providing a first mold;

inserting a first electrical contact in said first mold;

inserting a second electrical contact in said first mold;

closing said first mold with a second mold;

injecting material for forming a sensor into said closed first and second molds;

curing said material; and

extracting said sacrificial insert from said sensor.

16. An electrochemical sensor, comprising:

a sensor base;

a sacrificial insert on said sensor base;

a first electrical contact and a second electrical contact in said sensor, said sacrificial insert positioned between said first electrical contact and said second electrical contact; and

plastic material on said sensor base and over said sacrificial insert, said plastic material of a formulation which allows removal of said sacrificial insert from said plastic material and said sensor base leaving a capillary channel in said casting material.

17. A tool for extracting a sacrificial insert from an electrochemical sensor, comprising:

a clamp for clamping a sacrificial insert in a stationary position;

a first block moveable relative to said clamp;

a drive member for moving said block relative to said clamp; and

an attachment member on said block to attach a sensor with a sacrificial insert onto said block.

19. A sensor, comprising:

a sensor body;

a first access window in said sensor body;

a second access window in said sensor body; and

an insert in said sensor body between said first access window and said second access window.