Formulation and Storage Method to Enhance the Enzyme and Sensor Stabilities

• US 20150160151A1
• Filed: 12/06/2013
• Published: 06/11/2015
• Est. Priority Date: 12/06/2013
• Status: Abandoned Application

• Current Assignee: Verily Life Sciences LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Liu, Zenghe, Yao, Huanfen
• Application Number:
  US14/098,790
• Publication Number:
  US 20150160151A1
• Time in Patent Office: Days
• US Class Current: 1/1
• 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

Abstract

An analyte sensor and method of making are provided. The analyte sensor includes a crosslinked, hydrophilic copolymer in contact with a surface of an electrode; and an analyte sensing component embedded within the crosslinked, hydrophilic copolymer, where the analyte sensing component is surrounded by a buffer having a predetermined buffering component and pH value and where the crosslinked, hydrophilic copolymer includes: backbone chains having first methacrylate-derived units, each having a first hydrophilic side chain; second methacrylate-derived units, each having a second hydrophilic side chain, where the first and second side chains are the same or different; third methacrylate-derived units; and hydrophilic crosslinks between third methacrylate-derived units in different backbone chains. The analyte sensor may be maintained at a humidity level of less than 25% to maintain its performance during storage.

Claims

1. An analyte sensor comprising:

a crosslinked, hydrophilic copolymer in contact with a surface of an electrode; and

an analyte sensing component embedded within the crosslinked, hydrophilic copolymer, where the analyte sensing component is surrounded by a buffer having a predetermined buffering component and pH value and where the crosslinked, hydrophilic copolymer includes;

backbone chains having

first methacrylate-derived units, each having a first hydrophilic side chain;

second methacrylate-derived units, each having a second hydrophilic side chain, where the first and second side chains are the same or different;

third methacrylate-derived units; and

hydrophilic crosslinks between third methacrylate-derived units in different backbone chains.

2. The analyte sensor of claim 1, where the analyte sensor is maintained at a humidity level of less than 25%.

3. The analyte sensor of claim 2, further comprising a container for storing the analyte sensor.

4. The analyte sensor according to claim 1, where the analyte sensing component comprises glucose oxidase.

5. The analyte sensor according to claim 4, where the buffer is PBS buffer at pH 7.4.

6. The analyte sensor according to claim 1, where the first methacrylate-derived units have the structure of formula (Ia):

7. The analyte sensor according to claim 1, where the first methacrylate-derived units have the structure:

8. The analyte sensor according to claim 1, where the second methacrylate-derived units have the structure of formula (II):

9. The analyte sensor according to claim 1, where the second methacrylate-derived units have the structure of formula:

(II);

10. The analyte sensor according to claim 1, where the hydrophilic crosslinks have the structure of formula (IIIa):

11. The analyte sensor according to claim 1, where the crosslinked, hydrophilic copolymer has a thickness of about 20 μ

m.

12. The analyte sensor according to claim 1, where

the first methacrylate-derived units are derived from 2-hydroxyethylmethacrylate;

the second methacrylate-derived units have the structure of formula (II);

13. A method of forming an analyte sensor with enhanced storage stability, the method comprising:

preparing a mixture of an analyte sensing component, an initiator, a first methylacrylate monomer having a first hydrophilic side chain, a dimethylacrylate monomer, a second methylacrylate monomer having a second hydrophilic side chain, and a buffer having a predetermined buffering component and pH value;

depositing the mixture onto a surface of an electrode; and

curing the deposited mixture to form an analyte sensor.

15. The method of claim 13, where the analyte sensing component is glucose oxidase.

16. The method of claim 13, where the buffer is phosphate buffer solution (PBS).

17. The method of claim 13, where the first methacrylate monomer or second methacrylate monomer is di(ethylene glycol) dimethacrylate.

18. The method of claim 13, where said first methacrylate monomer is 2-hydroxyethyl methacrylate (HEMA), said second methacrylate monomer is poly(ethylene glycol) methyl ether methacrylate (PEGMA), and said dimethylacrylate monomer is crosslinker di(ethylene glycol) dimethacrylate (DEGDMA).

14. The method of claim 14, further comprising:

storing the electrochemical sensor at a humidity level of less than 25%.

19. A bio-compatible device comprising:

a first bio-compatible layer defining a first side of the bio-compatible device;

a conductive pattern on the first bio-compatible layer;

an electronic component mounted to the conductive pattern; and

a second bio-compatible layer over the first bio-compatible layer, the electronic component, and the conductive pattern, where the second bio-compatible layer defines a second side of the bio-compatible device and where the bio-compatible device is maintained at a humidity level of less than 25%.

20. The bio-compatible device of claim 19, further comprising a container for holding the bio-compatible device.

21. The bio-compatible device of claim 20, where the humidity level is maintained for at least a predetermined amount of time during storage in the container.