Invasive multi-electrode electrochemical sensor

Abstract

To provide a low-cost invasive electrochemical sensor.SOLUTION: An invasive multi-electrode electrochemical sensor includes a substrate and a plurality of wire electrodes. Each wire electrode includes an electrically conductive core, an insulating sheath, and a plurality of gold fingers. Each insulating sheath substantially covers a corresponding electrically conductive core but exposes a proximal end and a free end of the corresponding electrically conductive core. Each wire electrode has a substrate section and an invasion section. The proximal end is located at the substrate section; the free end is located at the invasion section. The substrate section is located on the substrate; the invasion section extends outward from an edge of the substrate. The invasion sections of the wire electrodes are at least partially wound around one another in a spiral manner. The electrically conductive cores in substrate sections of the wire electrodes are electrically connected to gold fingers, respectively. At least part of the gold fingers is screen-printed on the substrate.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an invasive electrochemical sensor.

Background Art

[0002] Conventional electrochemical sensors can be used for detecting fluids. The test strip has its general structural form, and an electrochemical thermosensitive test strip usually has a detection region that can be dropped or immersed in the solution to be measured. However, conventional electrochemical test strips cannot be applied to invasive detection. However, for the continuous monitoring of many biological / biophysiological parameters, invasive detectors are more suitable than conventional non-invasive electrochemical test strips.

[0003] Therefore, a method of providing an invasive electrochemical sensor while keeping the manufacturing cost low is really worthy of consideration for those skilled in the art.

Summary of the Invention

[0004] The main object of the present invention is to provide an invasive electrochemical sensor with low cost.

[0005] To achieve the above and other objects, the present invention provides an invasive multi-electrode electrochemical sensor (hereinafter sometimes abbreviated as an electrochemical sensor) including a substrate, a plurality of filamentary electrodes, and a plurality of finger electrodes provided on the substrate. Each filamentary electrode includes a conductive core and an insulating film. Each insulating film substantially covers the corresponding conductive core, but exposes the proximal end and the free end of the corresponding conductive core. Each filamentary electrode has a substrate portion and an invasive portion. The proximal end is located in the substrate portion, and the free end is located in the invasive portion. The substrate portion is provided on the substrate, and the invasive portion extends outward from the edge of the substrate. At least a part of the invasive portions of these filamentary electrodes are spirally wound around each other. The conductive cores of these filamentary electrodes in the substrate portion are each electrically connected to these finger electrodes, and at least a part of these finger electrodes are screen-printed on the substrate.

[0006] The present invention realizes an invasive electrochemical sensor using a plurality of helically wound filamentary electrodes, and by electrically connecting these filamentary electrodes respectively using screen-printed gold fingers, it has many advantages such as low cost, disposable, small volume, and sensitive reactivity, and can solve the deficiencies of the prior art.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

[0008] Refer to FIGS. 1 to 4 showing the first embodiment of the present invention. The electrochemical sensor of the present invention can be used for invasive detection of a host. The host may be a human or other animals and plants, and the electrochemical sensor can be used to detect whether the host contains a target analyte, the concentration of the target analyte and / or other values necessary for detection. The target analyte may be, but is not limited to, compounds such as glycated hemoglobin, blood glucose, heavy metals, nitrates, nitrites, allergens, formaldehyde, dissolved oxygen, uric acid, dopamine, ascorbic acid, potassium ferricyanide, acetaminophen, halogen ions, sulfide ions, hydrogen peroxide solution, trivalent arsenic ions, lead ions, zinc ions, chromium ions, phenols, amino acids, etc. The numerical values to be detected may be, but are not limited to, physical parameters such as acid-base value and electrical conductivity. In a possible embodiment, the electrochemical sensor of the present invention can also be applied to a non-invasive detection environment used to detect an aqueous solution such as an environmental water sample. In this embodiment, the electrochemical sensor includes a substrate 10, three filamentary electrodes 20, three gold fingers 30, and a cover plate 40.

[0009] The material of the substrate 10 may be, but is not limited to, polypropylene, polyethylene terephthalate, polyimide, polyethylene, polyurethane, or polycarbonate.

[0010] Each filamentary electrode 20 includes a conductive core 21 and an insulating film 22 (see FIG. 5). Each insulating film 22 substantially covers the corresponding conductive core 21, but exposes the proximal end 211 and the free end 212 of the corresponding conductive core 21. Also, each filamentary electrode 20 has a substrate portion 23 and an intrusion portion 24. The proximal end 211 is located in the substrate portion 23, the free end 212 is located in the intrusion portion 24, the substrate portion 23 is provided on the substrate 10, the intrusion portion 24 extends outward from the edge of the substrate 10, and the length of the intrusion portion 24 extending outward may be greater than 10 mm. In the present embodiment, the intrusion portions 24 of the three filamentary electrodes 20 are spirally wound around each other. The advantage of the spiral winding is that the distance between the electrodes is short, the electrical resistance is small, and the detection accuracy is improved. Among them, the material of the conductive core 21 of the intrusion portion 24 of at least one filamentary electrode 20 is different from the material of the conductive cores 21 of the other filamentary electrodes 20. For example, the conductive cores of the three filamentary electrodes in the present embodiment may be used as a working electrode, an auxiliary electrode, and a pseudo / reference electrode, respectively. Depending on different analytes, the conductive cores of the three filamentary electrodes may be made of the materials shown in Table 1, but are not limited thereto. On the other hand, the insulating film 22 is made of an insulating material so that the conductive cores of different filamentary electrodes are not directly electrically connected to form a short circuit.

[0011]

Table 1

[0012] When the diameter Φ of the conductive core 21 is Φ ≤ 25 μm, it can be a metallic wire ultramicroelectrode (MWUME). When the diameter Φ of the conductive core 21 satisfies the relationship 25 μm < Φ < 1000 μm, it can be a metallic wire microelectrode (MWME). When the diameter Φ of the conductive core 21 is Φ ≥ 1000 μm, it can be a metallic wire electrode (MWE).

[0013] The finger electrodes 30 are provided on the substrate 10, and the conductive cores 21 (such as the proximal ends 211) of these filamentous electrodes 20 in the substrate portion 23 are electrically connected to these finger electrodes 30 respectively. The electrical connection form between the conductive core 21 and the finger electrode 30 may be soldering or an adhesive tape, but is not limited thereto. The finger electrodes 30 are printed on the substrate 10 by, for example, a screen printing method. The material of the finger electrodes 30 is, for example, a printed carbon adhesive or a printed silver paste. Also, surface treatment such as additional sputtering of a metal material such as platinum, gold, copper, silver, etc. can be performed on the printed carbon adhesive or the printed silver paste. In this embodiment, the finger electrodes 30 extend to the edge of the substrate 10.

[0014] The cover plate 40 is provided on the substrate 10 and completely fixes the substrate portion 23 of these filamentous electrodes 20 between the cover plate 40 and the substrate 10.

[0015] Referring to FIG. 5, the free end of the conductive core 21 is flush with the end face of the insulating film 22, protrudes from the end face of the insulating film 22, has an irregular surface, and can be surface-treated to show different forms such as the interior being sunken into the end face of the insulating film 22. And, in one embodiment, the free end 212 of the conductive core 21 sinks into one end face 221 of the insulating film 22 and satisfies the following relational expression: Hw / Φ < 50. Here, Hw is the depth at which the free end 212 is sunk into the end face 221. Thereby, a space for subsequent chemical modification of the free end of the conductive core can be ensured. For example, an enzyme layer (not shown) can be filled in a groove formed on the end face of the insulating film. In addition, as shown in FIG. 6, the free end 212 of at least one conductive core 21 is made of a material different from that of other parts of the conductive core 21. For example, the material of the free end of the conductive core is carbon, and the material of other parts is copper, which is suitable for different detection environments.

[0016] Referring to FIG. 7, the electrochemical sensor of the embodiments shown in FIGS. 1 to 4 can be used together with an electrochemical sensing relay 1. The electrochemical sensing relay 1 is electrically connected to each gold finger of the electrochemical sensor 2 respectively, and relays the signal sensed by the electrochemical sensor to a remote receiving source (such as a smartphone, computer or cloud server, etc.) to perform further calculations and / or display the calculation results.

[0017] Note that the number of the filamentary electrodes is adjustable. For example, in the embodiment shown in FIG. 8, the intrusion ends of the four mutually helically wound filamentary electrodes 20 may be used to detect more analytes simultaneously. Also, as shown in FIG. 9, the intrusion ends of the six filamentary electrodes 20 may be helically wound around the intrusion end of the linearly extending central filamentary electrode 20c, that is, the intrusion end of at least one linearly extending filamentary electrode can be used as the axis around which the intrusion ends of the other filamentary electrodes are helically wound.

[0018] Referring to FIG. 10, in one reproducibility test, several electrochemical sensors shown in FIG. 1 were immersed in two different aqueous solutions three times in sequence. As a result, the electrochemical sensors of the present invention show good reproducibility in the detection results of each aqueous solution.

[0019] Referring to FIG. 11, the electrochemical sensor equipped with three filamentary electrodes was immersed separately in 0.1M PBS (phosphate buffered saline) aqueous solution, 500 μM hydrogen peroxide (H2O2) aqueous solution and 1000 μM hydrogen peroxide aqueous solution. The material of the main part of the conductive core of the filamentary electrode is carbon, and the material of the free end is platinum. As a result, the electrochemical sensor of the present invention can surely measure different oxidation and reduction potential expressions in hydrogen peroxide aqueous solutions with different concentrations.

[0020] [Table 2] [Description of Reference Numerals]

[0021] 1: Electrochemical sensing relay 2: Electrochemical sensor 10: Substrate 20, 20c: Filamentary electrode 21: Conductive core 211: Proximal end 212: Free end 22: Insulating film 221: End face 23: Substrate part 24: Invasion part 30: Gold finger 40: Cover plate H w : Depth Φ: Diameter

Claims

1. A substrate; a plurality of filamentary electrodes including a conductive core and an insulating film, each of the insulating films substantially covering a corresponding one of the conductive cores but exposing a proximal end and a distal end of the corresponding one of the conductive cores, each of the filamentary electrodes having a base portion and an intrusion portion, the proximal end being located in the base portion and the free end being located in the intrusion portion, the base portion being disposed on the substrate, the intrusion portion extending outwardly from an edge of the substrate, and at least a portion of the intrusion portions of the filamentary electrodes being spirally wound around each other; and a plurality of gold fingers (connecting contacts) provided on the substrate, the conductive cores in the substrate portions of the thread-like electrodes being electrically connected to the gold fingers, at least a portion of the gold fingers being screen printed on the substrate.

2. 2. The invasive multi-electrode electrochemical sensor of claim 1, wherein the proximal ends of the thread electrodes are electrically connected to the gold fingers, respectively.

3. 3. The invasive multi-electrode electrochemical sensor of claim 2, wherein the proximal ends of the thread electrodes are welded to the gold fingers, respectively.

4. 2. The invasive multi-electrode electrochemical sensor of claim 1, wherein the conductive core has a diameter Φ that satisfies the following relationship: Φ≦25 μm.

5. 2. The invasive multi-electrode electrochemical sensor according to claim 1, wherein the conductive core has a diameter Φ, and the following relationship is satisfied: 25 μm<Φ<1000 μm.

6. 2. The invasive multi-electrode electrochemical sensor of claim 1, wherein Φ is a diameter of the conductive core, and Φ is ≥ 1000 μm.

7. 2. The invasive multi-electrode electrochemical sensor of claim 1, further comprising a cover plate provided on the substrate, wherein at least a portion of the substrate portion of the thread-like electrodes is fixed between the cover plate and the substrate.

Images