Method of depositing reagent material in a test sensor

• US 20090145756A1
• Filed: 12/10/2008
• Published: 06/11/2009
• Est. Priority Date: 12/10/2007
• Status: Active Grant

• Current Assignee: Ascensia Diabetes Care Holdings AG (PHC Holdings Corporation)
• Original Assignee: Bayer Healthcare LLC (Bayer AG)
• Inventors: Henley, Herbert JR., Zhu, Boru
• Granted Patent: US 8,609,180 B2
• Time in Patent Office: Days
• US Class Current: 204/403.140
• CPC Class Codes: B05C 5/0225 characterised by flow controlling means, e.g. valves, located proximate the outlet B05C5/0258, B05C5/0275 take precedence; supply valves upstream the coating head B05C11/1036
• CPC Class Codes: C12Q 1/004 mediator-assisted
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: G01N 27/128 Microapparatus
• 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 27/3272 Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels optical biosensors G01N33/52

Abstract

A method of depositing reagent on an electrochemical test sensor adapted to determine information relating to an analyte includes providing a base and forming an electrode pattern on the base. The method further includes depositing the reagent on at least the electrode pattern using a reagent-dispensing system. The reagent-dispensing system applies mechanical force to the reagent in the reagent-dispensing system to assist in providing a wet reagent droplet on at least the electrode pattern.

Claims

1. A method of depositing reagent on an electrochemical test sensor, the test sensor adapted to determine information relating to an analyte, the method comprising the acts of:

providing a base;

forming an electrode pattern on the base; and

depositing the reagent on at least the electrode pattern using a reagent-dispensing system, the reagent-dispensing system applying mechanical force to the reagent in the reagent-dispensing system to assist in providing a wet reagent droplet on at least the electrode pattern.

2. A method of forming an electrochemical test sensor, the test sensor being adapted to determine information relating to an analyte, the method comprising the acts of. providing a base;

forming an electrode pattern on the base;

providing a reagent-dispensing system for depositing reagent on at least the electrode pattern, the reagent-dispensing system including a compression member, a piston-needle assembly, an air chamber, a fluid chamber, a nozzle, and a body, the compression member having a compression-adjustment mechanism for adjusting the amount of compression, the piston-needle assembly having a closed position and an open position;

supplying the reagent into the fluid chamber, the fluid chamber having a fluid input and a fluid output, the fluid output having an open position and a closed position corresponding to the open and closed positions of the piston-needle assembly;

supplying pressurized air to the air chamber to cause the piston-needle assembly to compress the compression member, the piston-needle assembly being in the open position, the fluid output being in the open position; and

releasing the supplied pressurized air from the air chamber to allow the compression member to force the piston-needle assembly into the closed position, the piston-needle assembly mechanically forcing a portion of the reagent in the fluid chamber out of the nozzle, the portion of the reagent being deposited on at least the electrode pattern as a wet reagent droplet.

3. The method of claim 2, further comprising the acts of:

providing a lid; and

attaching the lid to the base to assist in forming a channel in the test sensor, the channel assisting in allowing a fluid sample to contact the reagent droplet deposited on at least the electrode pattern.

4. The method of claim 2, further comprising the acts of:

providing a spacer;

providing a lid; and

attaching the lid to the spacer and attaching the spacer to the base to assist in forming a channel in the test sensor, the channel assisting in allowing a fluid sample to contact the reagent droplet deposited on at least the electrode pattern.

5. The method of claim 2, further comprising the act of providing a solenoid valve to assist in supplying the pressurized air to the air chamber and to assist in releasing the supplied pressurized air from the air chamber.

6. The method of claim 2, wherein the solenoid valve is selectively opened or closed by an electrical trigger.

7. The method of claim 2, further comprising the acts of:

drying the wet reagent droplet to form a dry reagent layer;

providing a lid; and

attaching the lid to the base to assist in forming a channel in the test sensor, the channel assisting in allowing a fluid sample to contact the dry reagent layer on at least the electrode pattern.

8. A method of forming an electrochemical test sensor, the test sensor being adapted to determine information relating to an analyte, the method comprising the acts of:

providing a base;

forming an electrode pattern on the base;

providing a reagent-dispensing system for depositing reagent on at least the electrode pattern, the reagent-dispensing system including a solenoid control valve, a plunger, a compression member, and a nozzle, the nozzle having an output diameter, the solenoid control valve having an open position and a closed position;

supplying pressurized reagent; and

opening the control valve of the reagent-dispensing system to cause the pressurized reagent to be dispensed through the nozzle and deposited on at least the electrode pattern as a wet reagent droplet.

9. The method of claim 8, wherein the nozzle output diameter is from about 3.5 mils to about 9.5 mils.

10. The method of claim 8, further comprising the acts of locating the nozzle of the reagent-dispensing system at a dispensing height of from about 50 mils to about 600 mils above a top surface of the electrode pattern.

11. The method of claim 10, further comprising the acts of locating the nozzle of the reagent-dispensing system at a dispensing height of from about 375 mils to about 425 mils.

12. The method of claim 10, further comprising the acts of locating the nozzle of the reagent-dispensing system at a dispensing height of from about 200 mils to about 250 mils, wherein the electrode pattern is plasma treated.

13. The method of claim 8, further comprising the acts of:

providing a lid; and

attaching the lid to the base to assist in forming a channel in the test sensor, the channel assisting in allowing a fluid sample to contact the reagent droplet located on at least the electrode pattern.

14. The method of claim 8, further comprising the acts of:

providing a spacer;

providing a lid; and

attaching the lid to the spacer and attaching the spacer to the base to assist in forming a channel in the test sensor, the channel assisting in allowing a fluid sample to contact the reagent droplet located on at least the electrode pattern.

15. The method of claim 8, further comprising the acts of:

drying the wet reagent droplet to form a dry reagent layer;

providing a lid; and

attaching the lid to the base to assist in forming a channel in the test sensor, the channel assisting in allowing a fluid sample to contact the dry reagent layer located on at least the electrode pattern.

16. A method of forming an optical test sensor, the optical test sensor being adapted to determine information relating to an analyte, the method comprising the acts of:

providing a base;

providing a reagent-dispensing system for depositing reagent on the base, the reagent-dispensing system including a solenoid control valve, a plunger, a compression member, and a nozzle, the nozzle having an output diameter, the solenoid control valve having an open and a closed position;

supplying pressurized reagent;

opening the control valve of the reagent-dispensing system to cause the supplied pressurized reagent to be dispensed through the nozzle and deposited on the base as a wet reagent droplet;

drying the wet reagent droplet to form a dry reagent layer;

providing a lid; and

attaching the lid to the base to assist in forming a channel in the test sensor, the channel assisting in allowing a fluid sample to contact the dry reagent layer located on the base.

17. An electrochemical test sensor comprising a base, a lid, a plurality of electrodes and a dried reagent, the dried reagent including an enzyme, a mediator, and a sufficient amount of a multivalent salt such that dried reagent has a uniformity in which the ratio of the thinnest point to the thickest point is greater than about 0.2.

18. The electrochemical test sensor of claim 17, wherein the dried reagent has a uniformity in which the ratio of the thinnest point to the thickest point is greater than about 0.3.

19. The electrochemical test sensor of claim 17, wherein the dried reagent has a uniformity in which the ratio of the thinnest point to the thickest point is greater than about 0.4.

20. A method of forming an electrochemical test sensor, the method comprising:

providing a base and a lid,

forming a plurality of electrodes on at least one of the base and the lid;

placing reagent solution so as to be in contact with at least one of the electrodes, the reagent solution including an enzyme, a mediator, and a multivalent salt, the multivalent salt having a concentration greater than 40 mM in the reagent solution; and

drying the reagent solution after placement thereof.

21. The method of claim 20, wherein the multivalent salt is sodium sulfate, potassium sulfate, ammonium sulfate, dibasic sodium phosphate, dibasic potassium phosphate, dibasic ammonium phosphate, sodium oxalate, potassium oxalate, sodium succinate, potassium succinate or a combination thereof.

22. The method of claim 20, wherein the multivalent salt is a sulfate, a phosphate or a combination thereof.

23. The method of claim 20, wherein the multivalent salt has a concentration greater than 50 mM in the reagent solution.

24. The method of claim 23, wherein the multivalent salt has a concentration greater than 75 mM in the reagent solution.

25. The method of claim 20, wherein the dried reagent has a uniformity in which the ratio of the thinnest point to the thickest point is greater than 0.3.

26. A method of forming an electrochemical test sensor, the method comprising:

providing a base and a lid,

forming a plurality of electrodes on at least one of the base and the lid;

placing a reagent solution so as to be in contact with at least one of the electrodes, the reagent solution including an enzyme, a mediator, and an electrolyte, the electrolyte including at least 0.1 wt. % of the reagent solution; and

drying the reagent solution after placement thereof.

27. The method of claim 26, wherein the polyelectrolyte includes carboxymethyl cellulose (CMC), homopolymer and copolymers of arylic acid, malaic acid, styrenesulfonic acid, vinylsulfonic acid, copolymers or salts thereof.

28. The method of claim 26, wherein the reagent solution includes at least about 0.2 wt. % polyelectrolytes.

29. The method of claim 28, wherein the reagent solution includes at least about 0.3 wt. % polyelectrolytes.

30. The method of claim 26, wherein the dried reagent has a uniformity in which the ratio of the thinnest point to the thickest point is greater than 0.3.