Electrode systems for electrochemical sensors
An electrode system for an electrochemical sensor, such as a glucose sensor, is disclosed. The electrode system may include a working electrode, a reference electrode, and a counter electrode. The working electrode may comprise two layers of different metals, such as gold and platinum.
1 . An electrode system for an implantable electrochemical sensor, the electrode system comprising:
a substrate extending from a first end to a second end;
a bilayer working electrode comprising a first continuous layer comprising a first metallic material and a second continuous layer overlaying the first continuous layer, the second continuous layer comprising a second metallic material different from the first metallic material;
a reference electrode, the bilayer working electrode positioned closer to the first end of the substrate than the reference electrode;
a counter electrode; and
a plurality of wire parts connecting each of the bilayer working electrode, the reference electrode, and the counter electrode to a plurality of corresponding connector parts positioned proximate the second end of the substrate,
wherein the bilayer working electrode and the reference electrode are positioned on a first side of the substrate, and
wherein the counter electrode is positioned on a second side of the substrate opposite the first side of the substrate.
2 . The electrode system of claim 1 , wherein the electrochemical sensor is a glucose sensor.
3 . The electrode system of claim 1 , wherein the thickness of the first continuous layer is about 2.5-3.5 μm and the thickness of the second continuous layer is about 80-120 Å.
4 . The electrode system of claim 1 , wherein the reference electrode has a thickness of about 2.5-3.5 μm.
5 . The electrode system of claim 1 , wherein the counter electrode has a thickness of about 2.5-3.5 μm.
6 . The electrode system of claim 1 , wherein the substrate comprises two base layers.
7 . The electrode system of claim 6 , wherein at least one of the two base layers comprises polyimide (PI), polyethylene (PE), or polyethylene terephthalate (PET).
8 . The electrode system of claim 1 , further comprises a first polymer layer covering part of the bilayer working electrode and the reference electrode.
9 . The electrode system of claim 8 , wherein the first polymer layer comprises polyimide (PI).
10 . The electrode system of claim 8 , further comprises a second polymer layer covering part of the counter electrode.
11 . The electrode system of claim 10 , wherein the second polymer layer comprises polyimide (PI).
12 . The electrode system of claim 1 , wherein a length of the bilayer working electrode is from 1.3 to 1.5 mm.
13 . The electrode system of claim 1 , wherein a width of the substrate is about 0.36 mm.
14 . The electrode system of claim 1 , wherein the first metallic material comprises gold and the second metallic material comprises platinum.
15 . The electrode system of claim 1 , wherein the counter electrode comprises gold.
16 . An implantable glucose sensor comprising:
an electrode system comprising:
a substrate extending from a first end to a second end;
a bilayer working electrode positioned on a first side of the substrate, the bilayer working electrode further comprising:
a first continuous layer comprising gold, the first continuous layer comprising a thickness of about 2.5-3.5 μm;
a second continuous layer comprising platinum, the second continuous layer comprising a thickness of about 80-120 Å;
a reference electrode positioned on the first side of the substrate, the bilayer working electrode positioned closer to the first end of the substrate than the reference electrode;
a counter electrode positioned on a second side of the substrate opposite the first side; and
a plurality of wire parts connecting each of the bilayer working electrode, the reference electrode, and the counter electrode to a plurality of corresponding connector parts positioned proximate the second end of the substrate.
17 . The glucose sensor of claim 16 , wherein the reference electrode comprises silver.
18 . The glucose sensor of claim 16 , wherein the counter electrode comprises gold.
19 . The glucose sensor of claim 16 , wherein the reference electrode has a thickness of about 2.5-3.5 μm.
20 . The glucose sensor of claim 16 , wherein the counter electrode has a thickness of about 2.5-3.5 μm.