Method for manufacturing implantable micro-biosensor
A method for manufacturing an implantable micro-biosensor includes the steps of: a) providing a substrate, b) forming on a first surface of the substrate a first working electrode which at least includes a first sensing section including a first conductive material, c) forming on the first surface of the substrate at least one second working electrode which at least includes a second sensing section disposed proximate to at least one side of the first sensing section, and d) forming a chemical reagent layer which at least covers the first conductive material of the first sensing section and which reacts with the analyte to produce a product.
1. A method for manufacturing an implantable micro-biosensor, comprising the steps of:
a) providing a substrate having a first surface, wherein the first surface has a first sensing region to be implanted subcutaneously for measuring a physiological parameter of an analyte in a biological fluid;
b) forming on the first surface of the substrate a first working electrode which at least includes a first sensing section, a surface material of the first sensing section including a first conductive material;
c) forming on the first surface of the substrate at least one second working electrode which at least includes a second sensing section disposed proximate to at least one side of the first sensing section, a surface material of the second sensing section including a second conductive material different from the first conductive material, wherein both the second sensing section and the first sensing section are located at the first sensing region; and
d) forming a chemical reagent layer which at least covers the first conductive material of the first sensing section and which reacts with the analyte to produce a product,
wherein steps b) and c) are implemented simultaneously by the sub-steps of:
b 1 ) applying the second conductive material on the first surface of the substrate;
b 2 ) subjecting the second conductive material to patterning so as to divide the second conductive material into a first area and at least one second area separated from each other; and
b 3 ) applying the first conductive material at the first sensing region to cover at least a portion of the second conductive material of the first area to form the first sensing section of the first working electrode and to configure the second conductive material at the at least one second area as the at least one second working electrode.
2. The method according to claim 1 , wherein step b) further includes, after sub-step b 2 ), a sub-step of forming a first insulation layer on the first surface of the substrate so as to define the first sensing region on the first surface of the substrate.
3. The method according to claim 1 , wherein the second sensing section is formed to be spaced apart from the at least one side of the first sensing section by a distance of up to 0.2 mm.
4. The method according to claim 1 , wherein the second sensing section is formed to extend along and be spaced apart from at least a portion of a periphery of the first sensing section, such that a ratio of the portion of the periphery of the first sensing section to a total of the periphery of the first sensing section ranges from 30% to 100%.
5. The method according to claim 1 , wherein sub-step b 2 ) forms two of the at least one second area so as to permit the second sensing section of each of two of the at least one second working electrode to be formed in sub-step b 3 ), wherein second sensing sections of two of the the at least one second working electrode are disposed, respectively, along two opposite sides of the first sensing section of the first working electrode.
6. The method according to claim 1 , wherein sub-step b 1 ) is implemented by a screen printing process.
7. The method according to claim 1 , wherein sub-step b 3 ) is implemented by a plating process.
8. The method according to claim 1 , wherein sub-step b 2 ) is implemented by a laser engraving process.
9. The method according to claim 1 , wherein step d) is implemented by immersing the substrate formed with the first and second working electrodes into a solution containing a chemical reagent.
10. The method according to claim 9 , wherein the chemical reagent simultaneously covers the first conductive material of the first sensing section and the second conductive material of the second sensing section.
11. The method according to claim 1 , wherein the first conductive material is selected from the group consisting of a noble metal, a noble metal derivative, and a combination thereof, and the noble metal is selected from the group consisting of gold, platinum, palladium, iridium, and combinations thereof.
12. The method according to claim 1 , comprising an additional step:
e) forming on the substrate a counter electrode which cooperates with the first working electrode to measure the physiological parameter of the analyte.
13. The method according to claim 12 , comprising another additional step:
f) forming on the substrate a reference electrode which is spaced apart from the counter electrode and which is free of an electrical connection with the counter electrode.
14. The method according to claim 13 , wherein steps e) and f) are implemented simultaneously by sub-steps including:
i) forming a backing material layer on a second surface of the substrate which is opposite to the first surface of the first surface;
ii) subjecting the backing material layer to patterning so as to divide the backing material layer into a third area and a fourth area which are separated from each other and which are free of an electrical connection with each other, such that the backing material layer at the third area is configured as the counter electrode; and
iii) forming a reference electrode material on at least a portion of the backing material layer at the fourth area to obtain the reference electrode.
15. The method according to claim 14 , further comprising a sub-step after sub-step ii), of forming a second insulation layer on the second surface of the substrate so as to define a second sensing region.
16. The method according to claim 13 , wherein steps of e) and f) are implemented simultaneously by sub-steps including:
i′) forming a backing material layer on a second surface of the substrate which is opposite to the first surface of the substrate;
ii′) applying a precursor material on at least a portion of the backing material layer;
iii′) subjecting the backing material layer and the precursor material to patterning so as to divide the second surface into a third area and a fourth area which are separated from each other and which are free of an electrical connection with each other, such that the backing material layer at the third area is configured as the counter electrode and at least a portion of the backing material layer at the fourth area is covered with the precursor material; and
iv′) converting the precursor material on the backing material layer at the fourth area to a reference electrode material to obtain the reference electrode.
17. The method according to claim 16 , wherein the backing material layer is formed as a layered-configuration selected from the group consisting of a single-layered configuration and a multi-layered configuration, each of which is made from a material selected from the group consisting of carbon, silver, a combination thereof.
18. The method according to claim 16 , further comprising a sub-step after sub-step iii′), of forming a second insulation layer on the second surface of the substrate so as to define a second sensing region.