Uricase enzyme biosensors and fabrication method thereof, sensing systems and sensing circuits comprising the same

• US 20070227884A1
• Filed: 06/07/2006
• Published: 10/04/2007
• Est. Priority Date: 04/04/2006
• Status: Abandoned Application

• Current Assignee: National Yunlin University of Science and Technology
• Original Assignee: National Yunlin University of Science and Technology
• Inventors: Chou, Jung-Chuan, Chen, Yu-Sheng, Liao, Wei-Li
• Application Number:
  US11/448,477
• Publication Number:
  US 20070227884A1
• Time in Patent Office: Days
• US Class Current: 204/403.10
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: C12Q 1/005 involving specific analytes or enzymes including groups of enzymes, e.g. oxydases; C12Q1/004 takes precedence

Abstract

A uricase enzyme biosensor and fabrication method thereof. The uricase enzyme biosensor includes a metal oxide semiconductor field effect transistor, a sensing unit including a substrate, a titanium dioxide film formed thereon and a uricase enzyme sensing film formed on the titanium dioxide film, and a conductive wire connecting with the metal oxide semiconductor field effect transistor and the sensing unit. The invention also provides a sensing system and a sensing circuit including the biosensor.

Claims

1. A uricase enzyme biosensor, comprising:

a metal oxide semiconductor field effect transistor;

a sensing unit comprising a substrate, a titanium dioxide film formed thereon and a uricase enzyme sensing film formed on the titanium dioxide film; and

a conductive wire connecting the metal oxide semiconductor field effect transistor and the sensing unit.

2. The uricase enzyme biosensor as claimed in claim 1, wherein the substrate is a semiconductor substrate.

3. The uricase enzyme biosensor as claimed in claim 1, wherein the conductive wire comprises an aluminum wire.

4. The uricase enzyme biosensor as claimed in claim 1, further comprising an insulating layer covering the surface of the sensing unit, exposing the uricase enzyme sensing film.

5. The uricase enzyme biosensor as claimed in claim 4, wherein the insulating layer comprises epoxy.

22. A uricase enzyme sensing system, comprising:

a uricase enzyme biosensor as claimed in claim 1;

a reference electrode applying a stabilized voltage;

a semiconductor characteristic instrument disposed on the uricase enzyme biosensor and connected with the reference electrode by a conductive wire; and

a light-isolation container containing the sensing unit of the uricase enzyme biosensor, the reference electrode and a test solution.

23. The uricase enzyme sensing system as claimed in claim 22, wherein the reference electrode is an Ag/AgCl reference electrode.

24. The uricase enzyme sensing system as claimed in claim 22, wherein the semiconductor characteristic instrument is a current/voltage instrument.

25. The uricase enzyme sensing system as claimed in claim 24, wherein the semiconductor characteristic instrument measures drain current and gate voltage.

26. The uricase enzyme sensing system as claimed in claim 22, wherein the conductive wire is an aluminum wire.

27. The uricase enzyme sensing system as claimed in claim 22, wherein the test solution is a uric acid-containing solution.

28. A sensing circuit, comprising:

a uricase enzyme biosensor as claimed in claim 1;

a first operational amplifier comprising an output port, a negative-phase input port and a non-negative-phase input port, wherein the output port and the negative-phase input port are connected to the uricase enzyme biosensor, and the non-negative-phase input port is connected to a first current source and a first port of a resistance; and

a second operational amplifier comprising an output port, a negative-phase input port and a non-negative-phase input port, wherein the output port and the negative-phase input port are connected to a second port of the resistance, and the non-negative-phase input port is connected to a second current source and the uricase enzyme biosensor.

29. The sensing circuit as claimed in claim 28, wherein the first and second operational amplifiers are negative feedback voltage buffers.

30. The sensing circuit as claimed in claim 28, wherein the sensing circuit exhibits two-stage operational amplification.

6. A method of fabricating a uricase enzyme biosensor, comprising:

providing a metal oxide semiconductor field effect transistor;

providing a sensing unit comprising a substrate, a titanium dioxide film formed thereon and a uricase enzyme sensing film formed on the titanium dioxide film; and

providing a conductive wire to connect the metal oxide semiconductor field effect transistor and the sensing unit.

7. The method of fabricating a uricase enzyme biosensor as claimed in claim 6, wherein the substrate is suitable for the deposition of TiO2 film.

8. The method of fabricating a uricase enzyme biosensor as claimed in claim 6, wherein the titanium dioxide film is formed on the substrate by sputtering.

9. The method of fabricating a uricase enzyme biosensor as claimed in claim 8, wherein the sputtering utilizes reaction gases comprising argon and oxygen.

10. The method of fabricating a uricase enzyme biosensor as claimed in claim 9, wherein argon and oxygen have a flow ratio of about 1:

1˜

4;

1.

11. The method of fabricating a uricase enzyme biosensor as claimed in claim 8, wherein the sputtering is radio frequency (RF) sputtering.

12. The method of fabricating a uricase enzyme biosensor as claimed in claim 8, wherein the sputtering has a working pressure of about 10˜

40 mTorr, a sputtering duration of about 0.5˜

1.5 hour and a RF power of about 120˜

180 W.

13. The method of fabricating a uricase enzyme biosensor as claimed in claim 6, wherein the uricase enzyme sensing film is formed on the titanium dioxide film by gel entrapment.

14. The method of fabricating a uricase enzyme biosensor as claimed in claim 13, wherein the steps of the gel entrapment comprise

mixing a light-sensitive polymer and a urate oxidase in a phosphate buffer solution;

titrating the solution on the titanium dioxide film; and

photopolymerizing the solution to form a uricase enzyme sensing film immobilized on the titanium dioxide film.

15. The method of fabricating a uricase enzyme biosensor as claimed in claim 14, wherein the light-sensitive polymer comprises polyvinyl alcohol.

16. The method of fabricating a uricase enzyme biosensor as claimed in claim 14, wherein the light-sensitive polymer and the urate oxidase solution have a weight ratio of about 5:

1˜

30;

1.

17. The method of fabricating a uricase enzyme biosensor as claimed in claim 14, wherein the solution is photopolymerized by exposure of UV light.

18. The method of fabricating a uricase enzyme biosensor as claimed in claim 14, wherein the urate oxidase is entrapped by the light-sensitive polymer to form the uricase enzyme sensing film.

19. The method of fabricating a uricase enzyme biosensor as claimed in claim 6, wherein the conductive wire is an aluminum wire.

20. The method of fabricating a uricase enzyme biosensor as claimed in claim 6, further comprising covering an insulating layer over the surface of the sensing unit, exposing the uricase enzyme sensing film.

21. The method of fabricating a uricase enzyme biosensor as claimed in claim 20, wherein the insulating layer comprises epoxy.