CONTINUOUS GLUCOSE MONITORING DEVICE
A wire-based three-pole sensor for subcutaneous insertion includes a working electrode including a first split wire having a first flat surface, and a support sheet on the first flat surface. The first flat surface is created from a full wire having a circular cross-section with a portion removed. A reference electrode includes a second split wire having a second flat surface. The second flat surface is defined by a second chord across a circular cross-section of the second split wire. A counter electrode includes a third split wire having a third flat surface. The third flat surface is defined by a third chord across a circular cross-section of the third split wire. The second and third flat surfaces face each other. A cross-sectional diameter of the first split wire, the second split wire, and the third split wire coupled together is less than an inner diameter of an insertion needle.
1 . A wire-based three-pole electrochemical sensor for subcutaneous insertion comprising:
a working electrode comprising a first split wire having a first flat surface along a length of the first split wire, and a support sheet on the first flat surface, the first flat surface created from a first full wire having a circular cross-section with a portion removed;
a reference electrode comprising a second split wire having a second flat surface along a length of the second split wire, the second flat surface created from a second full wire defined by a second chord across a circular cross-section of the second split wire; and
a counter electrode comprising a third split wire having a third flat surface along a length of the third split wire, the third flat surface created from a third full wire defined by a third chord across a circular cross-section of the third split wire;
wherein the second flat surface and the third flat surface face toward each other;
wherein a cross-sectional diameter of the first split wire, the second split wire, and the third split wire coupled together is less than an inner diameter of an insertion needle.
2 . The sensor of claim 1 , wherein the support sheet comprises carbon.
3 . The sensor of claim 1 , wherein the support sheet comprises graphene, pyrrole or polyaniline.
4 . The sensor of claim 1 , wherein the support sheet is electrically conductive and electrically coupled to the flat surface of the first split wire.
5 . The sensor of claim 1 , further comprising a sensing chemistry deposited on the support sheet.
6 . The sensor of claim 1 , further comprising a polymer layer over the support sheet.
7 . The sensor of claim 1 , wherein:
the circular cross-section with the portion removed of the first split wire of the working electrode forms a semicircular cross-section;
the second chord across the circular cross-section of the second split wire of the reference electrode forms a semicircular cross-section; and
the third chord across the circular cross-section of the third split wire of the counter electrode forms a semicircular cross-section.
8 . The sensor of claim 1 , wherein:
the circular cross-section with the portion removed of the first split wire of the working electrode forms a rectangular cross-section;
the second chord across the circular cross-section of the second split wire of the reference electrode forms a semicircular cross-section; and
the third chord across the circular cross-section of the third split wire of the counter electrode forms a semicircular cross-section.
9 . The sensor of claim 1 , wherein the second split wire and the third split wire each have a surface area of 82% of the respective second full wire or third full wire having the same diameter.
10 . The sensor of claim 1 , wherein:
a cross-sectional area of the second split wire of the reference electrode is 30% to 70% of the cross-section of the second full wire; and
a cross-sectional area of the third split wire of the counter electrode is 30% to 70% of the cross-section of the third full wire.
11 . A wire-based three-pole electrochemical sensor for subcutaneous insertion comprising:
a working electrode comprising a first split wire having a first flat surface along a length of the first split wire, and a support sheet on the first flat surface comprising carbon, and a sensing chemistry deposited on the support sheet, the first flat surface created from a first full wire having a circular cross-section with a portion removed;
a reference electrode comprising a second split wire having a second flat surface along a length of the second split wire, the second flat surface created from a second full wire defined by a second chord across a circular cross-section of the second split wire; and
a counter electrode comprising a third split wire having a third flat surface along a length of the third split wire, the third flat surface created from a third full wire defined by a third chord across a circular cross-section of the third split wire;
wherein the second flat surface and the third flat surface face toward each other;
wherein a cross-sectional diameter of the first split wire, the second split wire, and the third split wire coupled together is less than an inner diameter of an insertion needle.
12 . The sensor of claim 11 , wherein the support sheet further comprises graphene, pyrrole or polyaniline.
13 . The sensor of claim 11 , wherein the support sheet is electrically conductive and electrically coupled to the flat surface of the first split wire.
14 . The sensor of claim 11 , further comprising a polymer layer over the support sheet.
15 . The sensor of claim 11 , wherein:
the circular cross-section with the portion removed of the first split wire of the working electrode forms a semicircular cross-section;
the second chord across the circular cross-section of the second split wire of the reference electrode forms a semicircular cross-section; and the third chord across the circular cross-section of the third split wire of the counter electrode forms a semicircular cross-section.
16 . The sensor of claim 11 , wherein:
the circular cross-section with the portion removed of the first split wire of the working electrode forms a rectangular cross-section;
the second chord across the circular cross-section of the second split wire of the reference electrode forms a semicircular cross-section; and
the third chord across the circular cross-section of the third split wire of the counter electrode forms a semicircular cross-section.
17 . The sensor of claim 11 , wherein the second split wire and the third split wire each have a surface area of 82% of the respective second full wire or third full wire having the same diameter.
18 . The sensor of claim 11 , wherein:
a cross-sectional area of the second split wire of the reference electrode is 30% to 70% of the cross-section of the second full wire; and
a cross-sectional area of the third split wire of the counter electrode is 30% to 70% of the cross-section of the third full wire.