Method for formulating and immobilizing a protein matrix and a protein matrix for use in a sensor

• US 20030077772A1
• Filed: 12/27/2001
• Published: 04/24/2003
• Est. Priority Date: 10/23/2001
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Shah, Rajiv, Montalvo, Rudolph A., Reghabi, Bahar, Zhang, Yanan
• Granted Patent: US 7,192,766 B2
• Time in Patent Office: Days
• US Class Current: 435/177
• CPC Class Codes: C07K 1/1077 by covalent attachment of residues other than amino acids or peptide residues, e.g. sugars, polyols, fatty acids
• CPC Class Codes: C12Q 1/54 involving glucose or galactose
• CPC Class Codes: Y10S 435/817 Enzyme or microbe electrode

Abstract

A method for formulating and immobilizing a protein and a protein matrix formed by the method. The protein matrix preparation method results in a physically and chemically stable protein matrix that has low swelling, non-leaching, high activity, and high mechanical strength properties. The method includes cross-linking and hardening the protein mixture and using a mold to form a protein into a desired shape and size.

Claims

1. A method for formulating a protein comprising:

combining a protein mixture with a cross-linking reagent;

placing the protein mixture into a mold after combining the protein mixture with a cross-linking reagent;

hardening the protein mixture; and

removing the hardened protein mixture from the mold.

2. A method for formulating a protein according to claim 1, wherein hardening the protein mixture comprises exposing the protein mixture to a non-liquid cross-linking process.

3. A method for formulating a protein according to claim 2, wherein hardening the protein mixture further comprises incubating the protein mixture prior to exposing the protein mixture to the non-liquid cross-linking process.

4. A method for formulating a protein according to claim 2, wherein hardening the protein mixture further comprises immersing the protein mixture in a cross-linking solution after exposing the protein solution to the non-liquid cross-linking process.

5. A method for formulating a protein according to claim 2, wherein exposing the protein mixture to a non-liquid cross-linking process comprises exposing the protein mixture to a vapor phase that is approximately 12.5% (w/w) glutaraldehyde for approximately 16 hours.

6. A method for formulating a protein according to claim 3, wherein incubating the protein mixture comprises maintaining the protein mixture at approximately room temperature for approximately two hours.

7. A method for formulating a protein according to claim 4, wherein immersing the protein mixture in a cross-linking solution comprises submerging the protein mixture in a buffered solution that is approximately 2.5% (w/w) glutaraldehyde for approximately one hour.

8. A method for formulating a protein according to claim 1, wherein the protein mixture comprises glucose oxidase and human serum albumin.

9. A method for formulating a protein according to claim 1, wherein the cross-linking reagent is glutaraldehyde.

10. A method for formulating a protein according to claim 8, wherein the cross-linking reagent is glutaraldehyde.

11. A method for formulating a protein according to claim 1, wherein the cross-linking reagent is selected from a group consisting of glutaraldehyde, disuccinimidyl suberate (DSS), and 1-Ethyl-3 (3-Dimethylaminopropyl) Carbodiimide (EDC).

12. A method for formulating a protein according to claim 8, wherein the glucose oxidase has a concentration that is between approximately 67,000 U/ml and 150,000 U/ml.

13. A method for formulating a protein according to claim 9, wherein the human serum albumin has a concentration that is between approximately 23% (w/v) and 32.5% (w/v).

14. A method for formulating a protein according to claim 12, wherein the human serum albumin has a concentration that is between approximately 23% (w/v) and 32.5% (w/v).

15. A method for formulating a protein according to claim 1, wherein the mold is configured to form the protein mixture into at least one elongated rope-like structure.

16. A method for formulating a protein according to claim 15, wherein the method further comprises cutting the at least one elongated rope-like structure into pieces.

17. A method for formulating a protein according to claim 15, wherein the elongated rope-like structure is semi-cylindrical.

18. A method for formulating a protein according to claim 1, wherein the mold comprises:

a block with a surface wherein the surface has at least one recess in it; and

wherein the protein mixture is placed in the recess when it is placed into the mold.

19. A method for formulating a protein according to claim 18, wherein the recess comprises at least one channel.

20. A method for formulating a protein according to claim 19, wherein the recess is semi-cylindrical.

21. A method for formulating a protein according to claim 19, wherein the recess comprises multiple intersecting channels.

22. A method for formulating a protein according to claim 1, wherein the method further comprises adding silicone to the protein mixture.

23. A method for formulating a protein according to claim 22, wherein adding silicone to the protein solution comprises:

obtaining silicone particles; and

adding the silicone particles to the protein mixture.

24. A method for formulating a protein according to claim 23, wherein the volume of the silicone particles is less than 20% of the volume of the protein mixture.

25. A method for formulating a protein according to claim 23, wherein mixing the silicone particles into the protein mixture occurs prior to the protein mixture being placed into the mold.

26. A method for formulating a protein according to claim 1, wherein the method further comprises washing the protein mixture after the completion of hardening the protein mixture.

27. A method for formulating a protein according to claim 1, wherein the method further comprises cutting the protein mixture into at least two pieces after removing the protein mixture from the mold.

31. A protein matrix formed according to the method of claim 1.

28. A sensor comprising:

a sensor body; and

an active protein disposed within the sensor body, the active protein comprising gluscose oxidase, human serum albumin, and a cross-linking reagent.

29. A sensor according to claim 28, wherein the active protein is hardened before it is disposed within the sensor body.

30. A sensor according to claim 28, wherein the cross-linking reagent is selected from a group consisting of glutaraldehyde, disuccinimidyl suberate (DSS), and 1-Ethyl-3 (3-Dimethylaminopropyl) Carbodiimide (EDC).