Method for sterilizing membrane comprising glucose oxidase and associated bio-sensor

1. A method for sterilizing a membrane comprising an oxidoreductase enzyme, the method comprising:

irradiating with gamma radiation the membrane comprising the oxidoreductase enzyme soaked in a phosphate buffer saline (PBS) buffer solution,

wherein the PBS buffer consists essentially of sodium phosphate dibasic, sodium acid phosphate, sodium chloride, glycine, N, N′-ethanediybis (N-carboxymethyl) dipotassium, sodium benzoate, and gentamicin sulphate in water.

2. The method of claim 1 , wherein the oxidoreductase enzyme is selected from the group consisting of glucose oxidase, lactate oxidase and glutamate oxidase.

3. The method of claim 2 , wherein the oxidoreductase enzyme is glucose oxidase.

4. The method of claim 1 , wherein the wherein the gamma radiation is conducted at a rate of more than 3 kGy/hour and a dose of at least 25 kGy.

5. The method of claim 1 , wherein the aqueous buffer solution is substantially free from organic components.

6. A method for sterilizing a membrane comprising glucose oxidase, the method comprising:

making a phosphate buffer saline (PBS) solution by dissolving a PBS buffer powder in water,

wherein the PBS buffer powder consists essentially of 50-55% wt sodium phosphate dibasic, 10-15% wt sodium acid phosphate, 16-22% wt sodium chloride, less than 10% wt glycine and N, N′-ethanediylbis (N-carboxymethyl) dipotassium, less than 10% wt sodium benzoate, and less than 1% wt gentamicin sulphate, and

irradiating with gamma radiation the membrane comprising glucose oxidase soaked in a phosphate buffer saline (PBS) solution,

wherein the gamma radiation is carried out in a range of from about 25 kGy to about 40 kGy at rate of about 20 kGy/hour.

7. The method of claim 1 , wherein a dose of the gamma radiation is in a range of from about 25 kGy to about 40 kGy.

8. The method of claim 1 , wherein a rate of the gamma radiation is about 20 kGy/hour.

9. The method of claim 1 , wherein the membrane is in a plastic container.

10. The method of claim 1 , wherein the membrane is in a biosensor.

11. The method of claim 10 , wherein the biosensor comprises a Pt electrode and an Ag/AgCl electrode.

12. The method of claim 6 , wherein the biosensor comprises a Pt electrode and an Ag/AgCl electrode.

13. A biosensor comprising the membrane sterilized using the method of claim 1 .

14. The biosensor of claim 13 , wherein the membrane comprises glucose oxidase and the sensitivity of the biosensor to glucose is about 80% of the sensitivity of a biosensor comprising a membrane comprising glucose oxidase without sterilization to glucose.

15. The biosensor of claim 13 , comprising a Pt electrode and an Ag/AgCl electrode.

16. A bioreactor comprising the biosensor of claim 13 .

17. A biosensor comprising a sterilized membrane that comprises glucose oxidase, wherein the membrane is sterilized by: irradiating with gamma radiation while the membrane comprising glucose oxidase is soaked in a phosphate buffer saline (PBS) solution,

wherein the PBS buffer is made by dissolving a PBS powder in water, wherein the PBS buffer powder consists essentially of 50-55% wt sodium phosphate dibasic, 10-15% wt sodium acid phosphate, 16-22% wt sodium chloride, less than 10% wt glycine and N, N′-ethanediylbis (N-carboxymethyl) dipotassium, less than 10% wt sodium benzoate, and less than 1% wt gentamicin sulphate, and

wherein the gamma radiation is carried out in a range of from about 25 kGy to about 40 kGy at rate of about 20 kGy/hour.

18. The biosensor of claim 17 , wherein the biosensor comprises a Pt electrode and an Ag/AgCl electrode.

19. The biosensor of claim 17 , wherein the sensitivity of the sterilized biosensor to glucose is about 80% of the sensitivity of a biosensor prior to sterilization.

20. A bioreactor comprising the biosensor of claim 17 .