Invasive multielectrode electrochemical sensors

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 invasive electrochemical sensors. [Background technology]

[0002] Conventional electrochemical sensors can be used to detect fluids, and test strips are a common structural form of such sensors. Electrochemical thermosensitive test strips usually have a detection area 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 continuous monitoring of many biological / biophysiological parameters, invasive detectors are more suitable than conventional non-invasive electrochemical test strips.

[0003] Therefore, methods for providing invasive electrochemical sensors while keeping manufacturing costs low are truly worthy of consideration by those in the field. Summary of the Invention

[0004] A primary object of the present invention is to provide a low cost invasive electrochemical sensor.

[0005] In order to achieve the above and other objects, the present invention provides an invasive multi-electrode electrochemical sensor (hereinafter sometimes abbreviated as an electrochemical sensor) comprising a substrate, a plurality of thread-like electrodes, and a plurality of gold fingers provided on the substrate, wherein each thread-like electrode comprises a conductive core and an insulating film, each insulating film substantially covering a corresponding conductive core but exposing a proximal end and a free end of the corresponding conductive core, each thread-like electrode having a substrate portion and an intrusion portion, the proximal end being located in the substrate portion and the free end being located in the intrusion portion, the substrate portion being provided on the substrate, the intrusion portion extending outward from the edge of the substrate, at least a portion of the intrusion portions of the thread-like electrodes being spirally wound around each other, the conductive cores in the substrate portions of the thread-like electrodes being electrically connected to the gold fingers, and at least a portion of the gold fingers being screen-printed on the substrate.

[0006] The present invention realizes an invasive electrochemical sensor using multiple spirally wound filament electrodes, and electrically connects each of these filament electrodes using screen-printed gold fingers, which has many advantages such as low cost, disposable, small volume, and sensitive reactivity, and can solve the shortcomings of the prior art. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view of a first embodiment of the present invention; [Figure 2] FIG. 1 is an exploded view of a first embodiment of the present invention. [Figure 3] FIG. 1 is an exploded view of the first embodiment of the present invention, in which the conductive cores are electrically connected to the gold fingers by welding. [Figure 4] FIG. 1 is a partially enlarged schematic view of a first embodiment of the present invention. [Figure 5] FIG. 2 is a cross-sectional schematic view of four conductive cores at their free ends. [Figure 6] FIG. 10 is a cross-sectional schematic view of a free end of a conductive core according to another embodiment. [Figure 7] FIG. 1 is a schematic diagram illustrating the combined use of an electrochemical sensor and an electrochemical sensing repeater of the present invention. [Figure 8] 1 is a schematic diagram of an embodiment of the penetration end of a filamentary electrode of the present invention. FIG. [Figure 9] FIG. 10 is a schematic diagram of another embodiment of the penetration end of the filamentary electrode of the present invention. [Figure 10] 1 shows the reproducibility test results of the electrochemical sensor of the present invention. [Figure 11] 1 is a cyclic voltammogram of an electrochemical sensor of the present invention for aqueous hydrogen peroxide solutions of different concentrations. [Figure 12] 1 is a current-time graph showing an electrochemical sensor of the present invention detecting an aqueous solution of hydrogen peroxide by an amperometric method. [Figure 13] 1 is a current-concentration linear regression graph showing the amperometric detection of aqueous hydrogen peroxide by an electrochemical sensor of the present invention. [Figure 14]FIG. 10 is a schematic diagram of another embodiment of the penetration end of the filamentary electrode of the present invention. [Figure 15] FIG. 10 is a schematic diagram of another embodiment of the penetration end of the filamentary electrode of the present invention. [Figure 16] FIG. 2 is a schematic diagram of another embodiment of an electrochemical sensor of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] 1 to 4 illustrate a 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 animal or plant. 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 ​​required for detection. The target analyte may be, but is not limited to, compounds such as glycated heme, blood glucose, heavy metals, nitrate, nitrite, allergens, formaldehyde, dissolved oxygen, uric acid, dopamine, ascorbic acid, potassium ferricyanide, acetaminophen, halogen ions, sulfide ions, hydrogen peroxide, trivalent arsenic ions, lead ions, zinc ions, chromium ions, phenols, and amino acids. The value to be detected may be, but is not limited to, a physical parameter such as acid-base value or electrical conductivity. In a possible embodiment, the electrochemical sensor of the present invention can also be applied to non-invasive detection environments, for example, to detect aqueous solutions such as environmental water samples. In this embodiment, the electrochemical sensor includes a substrate 10 , three thread 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 filamentous 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 free end 212 of the corresponding conductive core 21. Each filamentous electrode 20 also includes a substrate portion 23 and an insertion portion 24. The proximal end 211 is located in the substrate portion 23, and the free end 212 is located in the insertion portion 24. The substrate portion 23 is attached to the substrate 10, and the insertion portion 24 extends outward from the edge of the substrate 10. The outward extension of the insertion portion 24 may be greater than 10 mm. In this embodiment, the insertion portions 24 of the three filamentous electrodes 20 are spirally wound around each other. The advantages of spiral winding include a short inter-electrode distance, low electrical resistance, and improved detection accuracy. The material of the conductive core 21 in the insertion portion 24 of at least one filamentous electrode 20 is different from the material of the conductive core 21 in the other filamentous electrodes 20. For example, the conductive cores of the three filamentous electrodes in this embodiment are the working electrode, auxiliary electrode, and pseudo / reference electrode, respectively, and depending on the different analytes, the conductive cores of the three filamentous electrodes may be made of, but are not limited to, the materials shown in Table 1. Meanwhile, the insulating film 22 is made of an insulating material to prevent the conductive cores of different filamentous electrodes from being directly electrically connected to each other and forming a short circuit.

[0011] [Table 1]

[0012] When the diameter Φ of the conductive core 21 is 25 μm or less, 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 1000 μm or more, it can be a metallic wire electrode (MWE).

[0013] The gold fingers 30 are provided on the substrate 10, and the conductive cores 21 (e.g., proximal ends 211) of the substrate portions 23 of these filamentary electrodes 20 are electrically connected to these gold fingers 30, respectively. The electrical connection between the conductive cores 21 and the gold fingers 30 may be, but is not limited to, soldering or adhesive tape. The gold fingers 30 are printed on the substrate 10, for example, by screen printing, and the material of the gold fingers 30 may be, for example, printed carbon adhesive or printed silver paste. Alternatively, the printed carbon adhesive or printed silver paste may be subjected to surface treatment, such as additional sputtering of a metal material such as platinum, gold, copper, or silver. In this embodiment, the gold fingers 30 extend to the edges of the substrate 10.

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

[0015] Referring to FIG. 5 , the free end of the conductive core 21 can be surface-treated to exhibit different morphologies, such as being flush with the end surface of the insulating film 22, protruding from the end surface of the insulating film 22, having an irregular surface, or being recessed into the end surface of the insulating film 22. In one embodiment, the free end 212 of the conductive core 21 is recessed into one end surface 221 of the insulating film 22, satisfying the following relationship: Hw / Φ<50, where Hw is the depth to which the free end 212 is recessed into the end surface 221. This ensures space for subsequent chemical modification of the free end of the conductive core, for example, filling a groove formed in the end surface of the insulating film with an enzyme layer (not shown). In addition, as shown in FIG. 6 , the free end 212 of at least one conductive core 21 can be made of a material different from the material of the remaining portions of the conductive core 21. For example, the material of the free end of the conductive core can be carbon and the material of the remaining portions can be copper, which is suitable for different sensing environments.

[0016] 7, the electrochemical sensor of the embodiment shown in FIGS. 1 to 4 can be used together with an electrochemical sensing repeater 1. The electrochemical sensing repeater 1 is electrically connected to each gold finger of the electrochemical sensor 2, and can relay the signal sensed by the electrochemical sensor to a remote receiving source (e.g., a smartphone, a computer, or a cloud server) for further calculation and / or display of the calculation result.

[0017] The number of threadlike electrodes can be adjusted. For example, in the embodiment shown in FIG. 8, the entry ends of four threadlike electrodes 20 spirally wound around each other may be used to simultaneously detect more analytes. Alternatively, as shown in FIG. 9, the entry ends of six threadlike electrodes 20 may be spirally wound around the entry end of a linearly extending central threadlike electrode 20c. That is, the entry end of at least one linearly extending threadlike electrode can serve as the axis around which the entry ends of the other threadlike electrodes are spirally 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 each, and the electrochemical sensors of the present invention showed good reproducibility in the detection results of each aqueous solution.

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

[0020] [Table 2] [Explanation of symbols]

[0021] 1: Electrochemical sensing repeater 2: Electrochemical sensors 10: Circuit board 20, 20c: filament electrodes 21: Conductive core 211: Proximal end 212: Free end 22: insulating film 221: End face 23: Circuit board 24: Intrusion part 30: Gold Finger 40: Cover plate H w :Depth Φ: Diameter

Claims

1. A substrate; a plurality of filamentary electrodes, each comprising a conductive core and an insulating film, each insulating film substantially covering a corresponding conductive core but exposing a proximal end and a distal end of the corresponding conductive core, each 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 attached to the substrate, the intrusion portion extending outward 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 which are screen-printed on the substrate.

2. 10. 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 according to claim 1, wherein the diameter of the conductive core is Φ and the following relationship is satisfied: Φ≦25 μm.

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

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

7. 10. 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.

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