Urea biosensors and stabilization of urea biosensors at room temperature

Patent metadata

Field	Value
Publication number	US-11460431-B2
Application number	US-201916430028-A
Country	US
Kind code	B2
Filing date	Jun 3, 2019
Priority date	Apr 5, 2019
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

Disclosed is a urea biosensor that is stable at ambient temperature, and methods of making thereof.

First claim

We claim:

1. A urea biosensor comprising:
an ammonium-selective polymeric membrane;
an enzyme layer comprising urease on an outer surface of the ammonium-selective polymeric membrane;
a polymeric diffusion membrane on a surface of the enzyme layer to form part of a composite membrane; and
(i) polysaccharide that is over a combination of the polymeric diffusion membrane, the enzyme layer, and the ammonium-selective polymeric membrane or (ii) polysaccharide that is over a combination of the polymeric diffusion membrane, the enzyme layer, and the ammonium-selective polymeric membrane and that is added to the urease before the urease forms the enzyme layer on the ammonium-selective polymeric membrane, the polysaccharide for maintaining stable activity of the urease between the polymeric diffusion membrane and the ammonium-selective polymeric membrane.

2. The urea biosensor of claim 1 , further comprising:
a metal element comprising silver, platinum, or gold; and
an inner electrolyte solution between the metal element and the ammonium-selective polymeric membrane.

3. The urea biosensor of claim 1 , further comprising:
a metal element comprising silver/silver chloride; and
an inner electrode solution between the metal element and the ammonium-selective polymeric membrane.

4. The urea biosensor of claim 1 , wherein the polymeric diffusion membrane comprises a polymer matrix and an ammonium-selective ionophore in the polymer matrix.

5. The urea biosensor of claim 4 wherein the polymer matrix comprises one or more of: polyvinyl chloride, polyurethane, poly(tetrafluoroethylene), poly(methyl methacrylate), silicone rubber, or a mixture of: polyvinyl chloride, polyurethane, polv(tetrafluoroethylene), poly(methyl methacrylate), or silicone rubber.

6. The urea biosensor of claim 4 , wherein the polymer matrix comprises polyvinyl chloride.

7. The urea biosensor of claim 4 , wherein the ammonium-selective ionophore comprises one or more of: nonactin, monactin, dinactin, trinactin, tetranactin, narasin, hexaoxaheptacyclotritrtracontane, benzocrown ethers, cyclic depsipeptides, or a mixture of: nonactin, monactin, dinactin, trinactin, tetranactin, narasin, hexaoxaheptacyclotritrtracontane, benzocrown ethers, or cyclic depsipeptides.

8. The urea biosensor of claim 4 , wherein the ammonium-selective ionophore comprises nonactin.

9. The urea biosensor of claim 1 , wherein the urease is cross-linked.

10. The urea biosensor of claim 1 , wherein the polysaccharide comprises one or more of sucrose, trehalose, raffinose, or lactitol.

11. The urea biosensor of claim 1 wherein the polymeric diffusion membrane comprises a polymeric compound comprising polyurethane, poly(tetrafluoroethylene) ionomers, the perfluorosulfonate ionomer NATION®, poly-(2-hydroxymethyl methacrylate), polyvinyl chloride, cellulose acetate, or a mixture or copolymer of: polyurethane, poly(tetrafluoroethylene) ionomers, the perfluorosulfonate ionomer NAFION®, poly-(2-hydroxymethyl methacrylate), polyvinyl chloride, or cellulose acetate.

12. The urea biosensor of claim 1 , the polysaccharide comprises 10% sucrose.

13. A disposable cartridge housing the urea biosensor of claim 1 .

14. The disposable cartridge of claim 13 , further comprising an array of sensors, the sensors comprising the urea biosensor.

15. A clinical analyzer for performing in vitro diagnostics, the clinical analyzer comprising the urea biosensor of claim 1 .

16. A method for making a urea biosensor, comprising:
casting urease in solution on an outer surface of an ammonium ion-selective membrane of an electrode to form an enzyme layer;
applying a diffusion barrier on a surface of the enzyme layer;
after the diffusion barrier is applied to the enzyme layer, applying a polysaccharide solution to a structure comprising the diffusion barrier, the enzyme laver, and the ammonium ion-selective membrane of the electrode; and
drying the structure to form part of the urea biosensor.

17. The method of claim 16 , wherein the urease is cross-linked.

18. The method of claim 16 , wherein the urease is cross-linked by a chemical comprising one or more of: glutaraldehyde, 1,4-diisocyanatobutane, 1,2,7,8-diepoxyoctane, or 1,2,9,10-diepoxydecane.

19. The method of claim 16 , wherein the electrode comprises silver, platinum, or gold.

20. The method of claim 16 , wherein the electrode comprises silver/silver chloride electrode.

21. The method of claim 16 , wherein the polysaccharide solution comprises sucrose, trehalose, raffinose, or lactitol.

22. The method of claim 16 , wherein the diffusion barrier comprises one or more of: polyurethane, poly(tetrafluoroethylene) ionomers, the perfluorosulfonate ionomer NAFION®, poly-(2-hydroxymethyl methacrylate), polyvinyl chloride, cellulose acetate, or a mixture or a copolymer of: polyurethane, poly(tetrafluoroethylene) ionomers, the perfluorosulfonate ionomer NAFION®, poly-(2-hydroxymethyl methacrylate), polyvinyl chloride, or cellulose acetate.

23. The method of claim 16 , wherein applying the polysaccharide solution comprises exposing the electrode to the polysaccharide solution for at least 30 minutes.

24. The method of claim 16 , wherein the urea biosensor is configured to maintain stable urea measurement performance after 5 months of dry storage at ambient temperature and 21 days of use.

25. The method of claim 16 , wherein a polysaccharide solution is added to the urease in solution before the urease in solution is cast.

26. The method of claim 16 , wherein the polysaccharide solution comprises 10% sucrose.

27. A method for making a urea biosensor, comprising:
casting urease in solution on an outer surface of ammonium-selective polymeric membrane to form an enzyme layer;
applying a polymeric diffusion membrane to a surface of the enzyme layer to form part of a composite membrane;
(i) applying polysaccharide solution to at least part of a structure comprising the polymeric diffusion membrane, the enzyme layer, and the ammonium-selective polymeric membrane after the polymeric diffusion membrane is applied to the surface of the enzyme layer, or (ii) both applying polysaccharide solution to the at least part of the structure, after the polymeric diffusion membrane is applied to the surface of the enzyme layer and adding polysaccharide solution to the urease in solution before the urease in solution is cast on the outer surface of the ammonium-selective polymeric membrane; and
drying the structure, wherein the polysaccharide solution maintains stable activity of the urease between the polymeric diffusion membrane and the ammonium-selective polymeric membrane.

28. The method of claim 27 , wherein the urease is cross-linked by a chemical comprising one or more of: glutaraldehyde, 1,4-diisocyanatobutane, 1,2,7,8-diepoxyoctane, or 1,2,9,10-diepoxydecane.

29. The method of claim 27 , wherein the polymeric diffusion membrane comprises one or more of: polyvinyl chloride, polyurethane, poly(tetrafluoroethylene), poly(methyl methacrylate), silicone rubber, or a mixture of: polyvinyl chloride, polyurethane, poly(tetrafluoroethylene), poly(methyl methacrylate), or silicone rubber.

30. A urea biosensor comprising:
an ammonium-selective polymeric membrane;
an enzyme layer comprising urease on an outer surface of the ammonium-selective polymeric membrane:
a polymeric diffusion

Assignees

• Instr Laboratory Co

Inventors

• Xu Xiaoxian
• Pamidi Prasad
• Yim Hyoungsik

Classifications

• C12Q1/002

  Electrode membranes · CPC title

• G01N33/70

  involving creatine or creatinine · CPC title

• C12Q1/005

  involving specific analytes or enzymes (including groups of enzymes, e.g. oxydases; C12Q1/004 takes precedence) · CPC title

• B01D69/144

  containing embedded or bound biomolecules · CPC title

• G01N33/96

  involving blood or serum control standard · CPC title