Composite modified electrode strip
The present invention provides a surface-modified electrode strip for measuring an electrochemical signal that is synergistically amplified by means of a nano-scaled gold particle layer and a lipid-soluble electron mediator layer. A biosensor comprising the electrode strip is also provided.
1. A surface-modified electrode strip for measuring electrochemical signals, comprising:
an insulating flat substrate;
an electrode system having a conductive film that is coated on one side of the insulating flat substrate to form a working electrode and a reference electrode that are segregated from each other;
an insulating layer, coated on the insulating flat substrate, that partially covers the electrode system so that one uncovered portion on the electrode system with the working electrode and the reference electrode becomes a conductive wire connecting end, and another uncovered portion on the electrode system with the working electrode and the reference electrode becomes an electrochemical reaction end;
a nano-scaled gold particle layer, which covers at least part of the electrochemical reaction end on the working electrode; and
a lipid-soluble electron mediator layer, which covers at least part of the electrochemical reaction end of the working electrode,
wherein said electrochemical reaction end of the working electrode further comprises a bridging element.
2. The electrode strip of claim 1 , wherein the size of the gold particle of the nano-scaled gold particle layer is less than 100 nanometers.
3. The electrode strip of claim 2 , wherein the size of the gold particle of the nano-scaled gold particle layer is about 5 to 50 nanometers.
4. The electrode strip of claim 3 , wherein the size of the gold particle of the nano-scaled gold particle layer is about 13 nanometers.
5. The electrode strip of claim 1 , wherein the nano-scaled gold particle layer completely covers the electrochemical reaction end.
6. The electrode strip of claim 1 , wherein the nano-scaled gold particle layer completely covers the electrochemical reaction end of the working electrode.
7. The electrode strip of claim 1 , wherein the nano-scaled gold particle layer partially covers the electrochemical reaction end of the working electrode.
8. The electrode strip of claim 1 , wherein the lipid-soluble electron mediator of the lipid-soluble electron mediator layer is selected from the group consisting of tetrathiafulvalene, tetracyanoquinodimethane, meldola blue and ferrocene or the derivatives thereof.
9. The electrode strip of claim 8 , wherein the lipid-soluble electron mediator is ferrocene or a ferrocene derivative.
10. The electrode strip of claim 9 , wherein the ferrocene derivative is 1,1′-ferrocenedicarboxylic acid.
11. The electrode strip of claim 1 , wherein the lipid-soluble electron mediator layer completely covers the electrochemical reaction end.
12. The electrode strip of claim 1 , wherein the lipid-soluble electron mediator layer completely covers the electrochemical reaction end of the working electrode.
13. The electrode strip of claim 1 , wherein the lipid-soluble electron mediator layer partially covers the electrochemical reaction end of the working electrode.
14. The electrode strip of claim 1 , wherein the bridging element has two functional groups, and the functional group is selected from the group consisting of carboxyl, thiol, hydroxy, amino, and aldo group.
15. The electrode strip of claim 14 , wherein the bridging element is an aldo-containing compound.
16. The electrode strip of claim 15 , wherein the bridging element is glutaraldehyde.
17. The electrode strip of claim 1 , wherein the electrochemical reaction end of the working electrode further comprises a binding element specifically binding to a target to form a complex.
18. The electrode strip of claim 17 , wherein the binding element is a protein, a nucleic acid sequence or a compound.
19. The electrode strip of claim 18 , wherein the protein is an antibody, an antigen, a protein ligand, or a receptor.
20. The electrode strip of claim 17 , wherein the binding element binds to the electrochemical reaction end of the working electrode through a bridging element.
21. The electrode strip of claim 17 , wherein the binding element-target complex and a redox enzyme form a redox enzyme layer.
22. The electrode strip of claim 21 , wherein the redox enzyme is selected from the group consisting of glucose oxidase, glucose reductase, lactose oxidase, pyruvate oxidase and hydrogen peroxidase.
23. The electrode strip of claim 21 , wherein the redox enzyme layer comprises a first antibody as the binding element, an antigen target and a second antibody-redox enzyme complex that binds to the antigen.
24. The electrode strip of claim 21 , wherein the redox enzyme layer comprises an antigen as the binding element, a first antibody that binds to the antigen and a second antibody- redox enzyme complex that binds to the first antibody.
25. A biosensor comprising the electrode strip of claim 1 and the detecting device.
26. The biosensor of claim 25 , wherein the detecting device is an electric current sensor consisting of a voltage output device, a signal-receiving device and a display device.