Invasive multi-electrode electrochemical sensor

Abstract

The invention provides an intrusive multi-electrode electrochemical sensor which comprises a substrate and a plurality of wire electrodes, each wire electrode comprises a conductive inner core, an insulating film and a plurality of golden fingers, each insulating film substantially wraps the corresponding conductive inner core but exposes a near side end and a free end of the corresponding conductive inner core, and the golden fingers are arranged on the substrate. Each wire electrode is provided with a base plate section and an invasion section, the near side end is located on the base plate section, the free end is located on the invasion section, the base plate section is arranged on the base plate, the invasion section extends outwards from the edge of the base plate, and at least parts of the invasion sections of the wire electrodes are spirally wound with one another; the conductive inner cores in the substrate sections of the plurality of wire electrodes are electrically connected with the plurality of golden fingers respectively, and at least one part of the plurality of golden fingers is printed on the substrate through a screen plate.

Description

Technical Field

[0001] This application relates to an invasive electrochemical sensor. Background Art

[0002] Existing electrochemical sensors can be used for fluid detection. Test pieces are a common structural form. Electrochemical sensing test pieces usually have a detection area for dropping or immersing a solution to be measured. However, existing electrochemical sensing test pieces cannot be applied to invasive detection. However, for the continuous monitoring of many biological physiological parameters, invasive detectors are more suitable than existing non-invasive electrochemical sensing test pieces.

[0003] Therefore, how to provide an invasive electrochemical sensor with a relatively low manufacturing cost is really worthy of consideration by those skilled in the art. Summary of the Invention

[0004] The technical problem to be solved by this application is to provide an invasive electrochemical sensor with a relatively low cost.

[0005] To achieve the above and other purposes, this application provides an invasive multi-electrode electrochemical sensor (hereinafter sometimes simply referred to as an electrochemical sensor), which includes a substrate, a plurality of filamentary electrodes, and a plurality of gold fingers disposed on the substrate. Each filamentary electrode includes a conductive inner core and an insulating film. Each insulating film substantially coats its corresponding conductive inner core but exposes a proximal end and a free end of its corresponding conductive inner core. Each filamentary electrode has a substrate segment and an invasive segment. The proximal end is located in the substrate segment, and the free end is located in the invasive segment. The substrate segment is disposed on the substrate, and the invasive segment extends outward from the edge of the substrate. At least a part of the invasive segments of the plurality of filamentary electrodes are helically wound around each other; the conductive inner cores in the substrate segments of the plurality of filamentary electrodes are respectively electrically connected to the plurality of gold fingers, and at least a part of the plurality of gold fingers are screen-printed on the substrate.

[0006] This application realizes an invasive electrochemical sensor by using a plurality of helically wound filamentary electrodes, and uses screen-printed gold fingers to be respectively electrically connected to the plurality of filamentary electrodes, which has many advantages such as low cost, disposable, small volume, and sensitive reactivity, thereby solving the deficiencies of the prior art.

[0007] Other effects and detailed content of the embodiments of this application are described below in conjunction with the drawings. Brief Description of the Drawings

[0008] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments recorded in the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0009] Figure 1 Isometric view of the first embodiment of the present application;

[0010] Figure 2 Exploded view of the first embodiment of the present application;

[0011] Figure 3 Exploded view of the first embodiment of the present application, wherein the conductive inner core is electrically connected to the gold finger by welding;

[0012] Figure 4 Partial enlarged schematic view of the first embodiment of the present application;

[0013] Figure 5 Cross-sectional view at the free ends of the four conductive inner cores;

[0014] Figure 6 Cross-sectional view of the free end of the conductive inner core in another embodiment;

[0015] Figure 7 Schematic diagram of the combined use of the electrochemical sensor of the present application and an electrochemical sensing repeater;

[0016] Figure 8 Schematic diagram of one embodiment of the invasive end of the filamentous electrode of the present application;

[0017] Figure 9 Schematic diagram of another embodiment of the invasive end of the filamentous electrode of the present application;

[0018] Figure 10 Reproducibility test results of the electrochemical sensor of the present application;

[0019] Figure 11 Cyclic voltammogram of the electrochemical sensor of the present application in hydrogen peroxide aqueous solutions of different concentrations;

[0020] Figure 12 Current-time graph of the electrochemical sensor of the present application for detecting hydrogen peroxide aqueous solution by amperometry;

[0021] Figure 13 Current-concentration linear regression graph of the electrochemical sensor of the present application for detecting hydrogen peroxide aqueous solution by amperometry;

[0022] Figure 14Schematic diagram of another embodiment of the invasive end of the filamentary electrode of the present application;

[0023] Figure 15 Schematic diagram of another embodiment of the invasive end of the filamentary electrode of the present application;

[0024] Figure 16 Schematic diagram of another embodiment of the electrochemical sensor of the present application.

[0025] Symbol description

[0026] 1: Electrochemical sensing repeater 2: Electrochemical sensor

[0027] 10: Substrate 20, 20c: Filamentary electrode

[0028] 21: Conductive inner core 211: Proximal end

[0029] 212: Free end 22: Insulating film

[0030] 221: End face 23: Substrate segment

[0031] 24: Invasive segment 30: Gold finger

[0032] 40: Cover sheet Hw: Depth

[0033] Φ: Diameter Detailed implementation manners

[0034] In the following implementation manners, the positional relationships described, including: up, down, left, and right, unless otherwise specified, are all based on the directions in which the components are shown in the drawings.

[0035] Please refer to Figures 1 to 4 , the one shown is the first embodiment of the present application. The electrochemical sensor of the present application can be used for invasive detection of a host, and the host can be a human or other animals and plants. 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 to be detected. The target analyte can 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, halide ions, sulfide ions, hydrogen peroxide, trivalent arsenic ions, lead ions, zinc ions, chromium ions, phenols, amino acids, etc. The values to be detected can be, but are not limited to, physical parameters such as pH value and conductivity. In possible implementation manners, the electrochemical sensor of the present application can also be applied to a non-invasive detection environment, such as for detecting aqueous solutions such as environmental water samples. In this embodiment, the electrochemical sensor includes a substrate 10, three filamentary electrodes 20, three gold fingers 30, and a cover sheet 40.

[0036] The material of the substrate 10 can be, but is not limited to, polypropylene, polyethylene terephthalate, polyimide, polyethylene, polyurethane, or polycarbonate.

[0037] Each filamentary electrode 20 includes a conductive inner core 21 and an insulating film 22 (please refer further to Figure 5 ). Each insulating film 22 substantially coats its corresponding conductive inner core 21 but exposes a proximal end 211 and a distal end 212 of its corresponding conductive inner core 21. In addition, each filamentary electrode 20 has a substrate segment 23 and an intrusion segment 24. The proximal end 211 is located in the substrate segment 23, and the distal end 212 is located in the intrusion segment 24. The substrate segment 23 is disposed on the substrate 10, and the intrusion segment 24 extends outward from the edge of the substrate 10. The length of the intrusion segment 24 extending outward can be greater than 10 mm. In this embodiment, the intrusion segments 24 of the three filamentary electrodes 20 are helically wound around each other. The advantage of helical winding is that the distance between the electrodes is short, the resistance is small, and the detection accuracy is improved. Among them, the material of the conductive inner core 21 of the intrusion segment 24 of at least one filamentary electrode 20 is different from the material of the conductive inner cores 21 of the other filamentary electrodes 20. For example, the conductive inner cores of the three filamentary electrodes in this embodiment serve as the working electrode, the auxiliary electrode, and the pseudo / reference electrode respectively. Depending on different analytes, the conductive inner cores of the three filamentary electrodes can be, but are not limited to, the materials listed in Table 1. On the other hand, the insulating film 22 is made of an insulating material to prevent direct electrical connection between the conductive inner cores of different filamentary electrodes and form a short circuit.

[0038] Table 1

[0039]

[0040] When the diameter Φ of the conductive inner core 21 is ≤ 25 μm, it can be used as a metallic wire ultramicroelectrode (MWUME). When the diameter Φ of the conductive inner core 21 satisfies the following relationship: 25 μm < Φ < 1000 μm, it can be used as a metallic wire microelectrode (MWME). When the diameter Φ of the conductive inner core 21 ≥ 1000 μm, it can be used as a metallic wire electrode (MWE).

[0041] The gold fingers 30 are provided on the substrate 10. The conductive inner cores 21 (such as the proximal ends 211) in the substrate segments 23 of the plurality of filamentous electrodes 20 are electrically connected to the plurality of gold fingers 30 respectively. The way of forming an electrical connection between the conductive inner core 21 and the gold finger 30 can be, but is not limited to, welding or pasting conductive tape. The gold fingers 30 are printed on the substrate 10 by, for example, screen printing. The material of the gold fingers 30 is, for example, printed carbon paste or printed silver paste. And, surface treatment can be further carried out on the printed carbon paste or printed silver paste, such as additionally sputtering metal materials such as platinum, gold, copper, silver, etc. In this embodiment, the gold fingers 30 extend to the edge of the substrate 10.

[0042] The cover sheet 40 is provided on the substrate 10 and fixes the substrate segments 23 of the plurality of filamentous electrodes 20 completely between the cover sheet 40 and the substrate 10.

[0043] Please refer to Figure 5 , the free ends of the conductive inner cores 21 can be surface-treated, so as to show different forms such as being flush with the end face of the insulating film 22, protruding from the end face of the insulating film 22, having an irregular surface and being recessed into the end face of the insulating film 22. And, in one of the implementation manners, the free end 212 of the conductive inner core 21 is recessed into one end face 221 of the insulating film 22 and satisfies the following relational expression: Hw / Φ < 50, where Hw is the depth of the free end 212 recessed into the end face 221, which can reserve space for subsequent chemical modification of the free end of the conductive inner core. For example, an enzyme layer (not shown) can be filled in the groove formed on the end face of the insulating film. In addition, as Figure 6 shown, the free ends 212 of at least one of the conductive inner cores 21 are made of a material different from that of other parts of the conductive inner core 21. For example, the material of the free end of the conductive inner core is carbon while the material of other parts is copper, so as to adapt to different detection environments.

[0044] Please refer to Figure 7 , Figures 1 to 4 shown, the electrochemical sensor of the embodiment can be used in conjunction with the electrochemical sensing repeater 1. The electrochemical sensing repeater 1 can be electrically connected to each gold finger of the electrochemical sensor 2 respectively, and transmit the signals sensed by the electrochemical sensor to a remote receiving element (such as a smart phone, a computer or a cloud server, etc.) for further calculation and / or display of the calculation result.

[0045] It should be noted that the number of the filamentous electrodes can be adjusted. For example, in the Figure 8 shown embodiment, the intrusion ends of the four mutually helically wound filamentous electrodes 20 can be used to detect more analytes simultaneously; in addition, as Figure 9As shown, the invasive end of the six-strand filamentous electrode 20 can be helically wound around the invasive end of the centrally located filamentous electrode 20c that extends linearly. That is to say, the invasive end of at least one linearly extending filamentous electrode can serve as the axis around which the invasive ends of other filamentous electrodes are helically wound.

[0046] Please refer to Figure 10 , in a reproducibility test, multiple Figure 1 electrochemical sensors as shown were successively immersed in two different aqueous solutions three times each. The results showed that the electrochemical sensors of the present application exhibited good reproducibility in the detection results for the respective aqueous solutions.

[0047] Please refer to Figure 11 , an electrochemical sensor with three filamentous electrodes was successively immersed in a 0.1 M PBS (phosphate buffered saline) aqueous solution, a 500 μM hydrogen peroxide (H 2 O 2 ) aqueous solution, and a 1000 M hydrogen peroxide aqueous solution. The main part of the conductive core of the filamentous electrode was made of carbon, and the free end was made of platinum. The results showed that the electrochemical sensors of the present application could indeed measure different oxidation and reduction potential performances in hydrogen peroxide aqueous solutions of different concentrations.

[0048] Please also refer to Figure 12 , the applicant tested the performance of the electrochemical sensor of the present application for detecting hydrogen peroxide aqueous solution by amperometry. The electrochemical sensor used had three filamentous electrodes. The main part of the conductive core of the filamentous electrode was made of carbon, and the free end was made of platinum. The applicant detected hydrogen peroxide aqueous solutions of different concentrations by amperometry under the working parameters shown in Table 2 below, that is, the concentration of the hydrogen peroxide aqueous solution was adjusted every 50 seconds. In the first ten times, it was increased by 100 μM each time, and in the last five times, it was increased by 200 μM each time. The final concentration was 2000 μM, and the oxidation working voltage was fixed at 600 mV. The results showed that the electrochemical sensor of the present application could sensitively detect the concentration change of the hydrogen peroxide aqueous solution, and the measured current value was highly linear with the concentration change (as Figure 13 shown), indicating that the electrochemical sensor of the present application had good accuracy.

[0049] Table 2

[0050]

[0051]

[0052] The above-described embodiments and / or implementation manners are merely used to illustrate the preferred embodiments and / or implementation manners for realizing the technology of the present application, and do not impose any formal restrictions on the implementation manners of the technology of the present application. Any person skilled in the art can make some modifications or decorations to other equivalent embodiments without departing from the scope of the technical means disclosed in the content of the present application, but should still be regarded as the same technology or embodiment as the present application in essence.

Claims

1. An invasive multi-electrode electrochemical sensor, characterized in that: The invasive multi-electrode electrochemical sensor comprises: a substrate; A plurality of wire-shaped electrodes, each of which comprises a conductive inner core and an insulating film, each of which substantially covers the corresponding conductive inner core but exposes a proximal end and a distal end of the corresponding conductive inner core, each of which comprises a substrate segment and an intrusion segment, the proximal end is located on the substrate segment, the free end is located on the intrusion segment, the substrate segment is disposed on the substrate, the intrusion segment extends outward from the edge of the substrate, and at least a portion of the intrusion segments of the plurality of wire-shaped electrodes are spirally wound around each other; and A plurality of gold finger connecting contacts are arranged on the substrate, the conductive inner cores in the substrate segments of the plurality of wire-shaped electrodes are electrically connected to the plurality of gold fingers respectively, and at least a part of the plurality of gold fingers is screen-printed on the substrate.

2. The invasive multi-electrode electrochemical sensor according to claim 1, characterized in that: The proximal ends of the plurality of wire electrodes are electrically connected to the plurality of gold fingers respectively. 3 . The invasive multi-electrode electrochemical sensor according to claim 2 , wherein the proximal ends of the plurality of wire electrodes are welded to the plurality of gold fingers, respectively.

4. The invasive multi-electrode electrochemical sensor according to claim 1, characterized in that: The diameter of the conductive inner core is Φ and satisfies the following relationship: Φ≦25 μm.

5. The invasive multi-electrode electrochemical sensor according to claim 1, characterized in that: The diameter of the conductive inner core is Φ and satisfies the following relationship: 25 μm<Φ<1000 μm.

6. The invasive multi-electrode electrochemical sensor according to claim 1, characterized in that: The diameter of the conductive inner core is Φ and satisfies the following relationship: Φ≧1000 μm.

7. The invasive multi-electrode electrochemical sensor according to claim 1, characterized in that: The invention further comprises a cover plate, which is arranged on the substrate and fixes at least a part of the substrate segments of the plurality of wire-shaped electrodes between the cover plate and the substrate.

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