Method for preparing a working electrode
The present invention relates to a method for the preparation of a working electrode, the method comprising application of a sensing material in several steps. Further, the present invention relates to an analyte sensor comprising the working electrode as well as to the use of the analyte sensor for detecting at least one analyte in a sample.
1 . A method for manufacturing a working electrode of an analyte sensor comprising the following steps:
(a) providing a sheet or roll of a raw substrate material comprising
a first side and a second side,
at least one conductive material being positioned on the first side of the substrate material;
(b) applying via cannula-coating a continuous flow of a sensing material to an application area on the first side of the substrate material; and
(c) obtaining the working electrode of the analyte sensor on the first side of the substrate material,
wherein the sensing material comprises
at least one enzyme and
at least one crosslinker.
2 . The method of claim 1 , wherein step (b) is performed only once.
3 . The method of claim 1 , wherein the at least one conductive material positioned on the first side of the substrate material is selected from gold, carbon, carbon paste and any combination thereof.
4 . The method of claim 1 , wherein the sensing material comprises at least one chemical crosslinker.
5 . The method of claim 1 , wherein the at least one crosslinker is present in the sensing material in an amount up to about 25% (w/w) based on the dry weight of the sensing material.
6 . The method of claim 1 , wherein
(i) the cannula has an inner diameter of about 0.3 mm to about 0.4 mm, and/or
(ii) the speed of the substrate material relative to the cannula during step (b) is in the range from about 1 mm/s to about 20 mm/s, and/or
(iii) the flow rate of the sensing material during step (b) is in the range from about 0.007 ml/min to about 0.05 ml/min, and/or
(iv) the distance between the cannula and the surface of the first side of the substrate material to which the sensing material is applied during step (b) is in the range from 50 μm to about 100 μm.
7 . The method of claim 6 , wherein
the cannula has an inner diameter of about 0.33 mm, and/or
the speed of the substrate material relative to the cannula during step (b) is in the range from about 2 mm/s to about 15 mm/s, and/or
the flow rate of the sensing material during step (b) is in the range from about 0.01 ml/min to about 0.03 ml/min.
8 . The method of claim 7 , wherein the flow rate of the sensing material during step (b) is about 0.015 ml/min.
9 . The method of claim 7 , wherein the distance between the cannula and the surface of the first side of the substrate material to which the sensing material is applied during step (b) is about 70 μm.
10 . The method of claim 1 , wherein after step (b) the sensing material is dried.
11 . The method of claim 10 , wherein after drying the sensing material of the working electrode has a dry total thickness in the range from about 3 μm to about 8 μm.
12 . The method of claim 1 and providing at least one further electrode.
13 . The method of claim 1 , wherein the sensing material comprises PEGDGE 500.
14 . The method of claim 1 , wherein the at least one crosslinker is present in the sensing material in an amount of about 0.5% (w/w) to about 25% (w/w) based on the dry weight of the sensing material.
15 . The method of claim 1 , wherein after drying the sensing material of the working electrode has a dry total thickness in the range from about 3 μm to about 6 μm.
16 . The method of claim 15 , wherein after drying the sensing material of the working electrode has a dry total thickness in the range from about 4 μm to about 5 μm.
17 . The method of claim 16 , wherein the obtaining of the working electrode comprises cutting the raw substrate material into pieces having the desired size.
18 . The method of claim 1 wherein the sensing material is applied as a wet layer.
19 . The method of claim 18 wherein the sensing material is applied having a wet layer thickness greater than about 20 μm in a single application.
20 . The method of claim 1 wherein the cannula-coating comprises moving the sheet or roll relative to a cannula and continuously flowing the sensing material from the cannula onto the application area.
21 . The method of claim 20 wherein the raw substrate material comprises numerous aligned working electrodes and the sensing material is applied continuously onto the aligned working electrodes.
22 . The method of claim 20 wherein the cannula-coating is applied as a continuous flow onto the sheet or roll as a wet layer having a wet layer thickness of greater than 20 μm.