Method for preparing an electrochemical sensing device and electrochemical sensing device

Abstract

The application provides a preparation method of an electrochemical sensing device and the electrochemical sensing device. A model of a flexible sensing element is designed by using modeling software, and a printing screen plate is designed and manufactured based on the model. A printing material of the flexible sensing element is prepared. A plurality of sensing electrode array layers of the flexible sensing element are printed on a flexible substrate layer by using a full-automatic screen printing machine to form a plurality of flexible sensing elements. A single flexible sensing element is cut, and the cut flexible sensing element is wound in a cylindrical structure with the sensing electrode array layer located on the inner side. A heat-shrinkable tube is sleeved on the outer side of the flexible sensing element and is heated and shrunk, so that the flexible sensing element is attached to the inner wall of the heat-shrinkable tube around the circumference of the heat-shrinkable tube to assemble a sampling suction head. The sampling suction head, a suction device, a micro electrochemical workstation and a signal processing equipment are connected and assembled to form the electrochemical sensing device. The electrochemical sensing device is simple in structure and easy to mass-produce.

Description

Technical Field

[0001] This application belongs to the field of electrochemical sensor technology, and more specifically, relates to a method for preparing an electrochemical sensing device and the electrochemical sensing device itself. Background Technology

[0002] Electrochemical sensing has always been a cutting-edge technology in the fields of chemical and biological sensors, playing a vital role in analytical chemistry. As a key component of electrochemical sensors, electrodes are crucial in determining the performance of the manufactured sensors.

[0003] Based on the physical form of the electrochemical interface, electrodes can be divided into three categories: The first category is traditional disk electrodes, including glassy carbon electrodes (GCE) and noble metal electrodes (such as Au, Pt). Due to their good stability and reproducibility, they have been widely used. The second category is traditional planar screen-printed electrodes (SPE), which typically appear in the form of integrated three electrodes. Planar screen-printed electrodes (SPE) are characterized by ease of use, simplicity, and low cost, making them particularly suitable for everyday applications such as point-of-care testing (POCT). The third category consists of self-made materials developed as self-supporting working electrodes (WEs), including 2D / 3D carbon / metal-based materials (e.g., graphene foam, gold / silver rods). Their inherent nanofunctional surfaces provide a large sensing surface and good catalytic activity, thus facilitating the construction of high-performance electrochemical sensors.

[0004] While the aforementioned electrodes play a role in constructing various sensors, limitations and inherent defects in their manufacturing process hinder their application. Typically, the inherent limitations of disk electrodes stem primarily from their inability to operate independently, often requiring separate counter and reference electrodes (CE and RE). This inevitably leads to sensor redundancy, larger device size, lower integration, and increased sample solution consumption. Furthermore, the cumbersome disk three-electrode sensing system introduces systematic errors due to human intervention, negatively impacting the accuracy and precision of test results. To obtain sensors with high sensitivity and wide response ranges, most disk electrodes require functional material decoration, compromising the sensor's inherent simplicity. In contrast, the integrated three-electrode design of traditional screen-printed electrodes simplifies sensor setup and enables miniaturization of measurement dimensions. However, the planar interface of planar screen-printed electrodes (SPEs) in related technologies results in a small solid-liquid contact area, low liquid utilization, and use in open environments. Additionally, due to the small working area of ​​traditional SPE electrodes, the limited sensing area still requires further material modification. As for self-supported working electrodes (WE) prepared by researchers themselves, they are rarely used in the laboratory due to unavoidable individual differences, poor reproducibility, and technical difficulties in large-scale preparation.

[0005] Therefore, it is essential to provide an electrochemical sensing device that is simple in structure, easy to operate, has high liquid utilization rate, and is easy to mass-produce. Summary of the Invention

[0006] The purpose of this application is to provide a method for preparing an electrochemical sensing device and an electrochemical sensing device, so as to solve the technical problems of complex electrode structure and cumbersome operation of existing electrochemical sensing devices.

[0007] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0008] In a first aspect, this application provides a method for preparing an electrochemical sensing device, comprising the following steps:

[0009] Models of flexible sensing elements are designed using modeling software, and printed stencils are designed and fabricated based on these models.

[0010] Prepare printing materials for flexible sensing elements; wherein, the printing materials include flexible substrate material and printing paste;

[0011] The printing material is designed according to the model using a fully automatic screen printing machine, and multiple sensing electrode array layers are printed on a flexible substrate using the printing screen to form multiple flexible sensing elements.

[0012] A single flexible sensing element is cut, and the cut flexible sensing element is wound into a cylindrical structure with the sensing electrode array layer on the inside. A heat shrink tube is placed on the outside of the flexible sensing element and heated to shrink it, so that the flexible sensing element is attached to the inner wall of the heat shrink tube around the circumference of the heat shrink tube, and assembled into a sampling tip.

[0013] The sampling tip, suction device, micro electrochemical workstation, and signal processing equipment are connected and assembled into an electrochemical sensing device.

[0014] According to a preferred embodiment, the step of designing a model of the flexible sensing element using modeling software and designing and fabricating a printing screen based on the model further includes:

[0015] Based on the model of flexible sensing element, frame wire mesh, electrode lead mesh, insulating layer mesh, working electrode and counter electrode mesh, and reference electrode mesh were fabricated respectively.

[0016] The frame mesh plate has printed holes for the outer frame of each flexible sensing element, the electrode lead mesh plate has printed holes for the electrode leads and lead connection points, the insulating layer mesh plate has printed holes for the insulating layer, the working electrode and counter electrode mesh plates have printed holes for the working electrode and counter electrode, and the reference electrode mesh plate has printed holes for the reference electrode.

[0017] According to a preferred embodiment, in the step of preparing the printing material for the flexible sensing element, the flexible substrate material includes a polyimide film, and the printing paste includes insulating ink, conductive silver paste, silver chloride paste, carbon paste ink, and carbon nanotube paste.

[0018] According to a preferred embodiment, the thickness of the polyimide film is 0.05 to 0.075 mm.

[0019] According to a preferred embodiment, the step of using a fully automatic screen printing machine to print the printing material according to the model design and using the printing screen to print multiple sensing electrode array layers on a flexible substrate to form multiple flexible sensing elements further includes:

[0020] Insulating ink is printed on the surface of the flexible substrate using the frame mesh to form the outer frame of each flexible sensing element;

[0021] Conductive silver paste is printed inside the outer frame of each flexible sensing element using the electrode lead mesh to form electrode leads and lead connection points.

[0022] Insulating ink is printed above the electrode leads of each flexible sensing element using the insulating mesh to form an insulating layer;

[0023] The working electrode and the counter electrode are formed by printing carbon paste ink and carbon nanotube paste on the insulating layer of each flexible sensing element using the aforementioned working electrode and counter electrode stencils.

[0024] The reference electrode is formed by printing silver chloride paste onto the insulating layer of each flexible sensing element using the reference electrode stencil.

[0025] According to a preferred embodiment, the step of using a fully automatic screen printing machine to print the printing material according to the model design and using the printing screen to print multiple sensing electrode array layers on a flexible substrate to form multiple flexible sensing elements further includes:

[0026] After each layer of screen printing is completed, it is placed in an oven and dried at 70℃~80℃ for 15min~20min.

[0027] According to a preferred embodiment, the step of cutting a single flexible sensing element, winding the cut flexible sensing element into a cylindrical structure with the sensing electrode array layer on the inside, and then heat-shrinking a heat-shrink tubing over the outside of the flexible sensing element so that the flexible sensing element is circumferentially attached to the inner wall of the heat-shrink tubing to assemble the sampling tip further includes:

[0028] The flexible sensing element is wound up, and the sensing electrode array layer is located on the inner wall of the flexible sensing element.

[0029] A mold is nested inside the flexible sensing element;

[0030] A heat shrink tubing is nested outside the flexible sensing element;

[0031] Heat shrinks the tube; and stretches it into a cone shape at the lower end by stress.

[0032] Remove the internal mold.

[0033] According to a preferred embodiment, during heat shrinking, the heat shrinking temperature is 110℃~120℃, and the heat shrinking time is 40s~80s.

[0034] Secondly, this application also provides an electrochemical sensing device, which is prepared by the aforementioned preparation method. The electrochemical sensing device includes an attraction device, a micro electrochemical workstation, a signal processing device, and a sampling tip. The sampling tip is detachably disposed at the lower end of the attraction device and is connected to the micro electrochemical workstation via a conductive connecting wire. The micro electrochemical workstation is detachably disposed in the middle of the attraction device and is communicatively connected to the signal processing device.

[0035] According to a preferred embodiment, the sampling tip includes a sampling element and a flexible sensing element, wherein the flexible sensing element is wound into a cylindrical structure, and a sensing electrode array layer is printed on the inner wall of the cylindrical flexible sensing element. The sampling element is sleeved on the outside of the flexible sensing element, and the flexible sensing element is attached to the inner wall of the sampling element circumferentially around the sampling element.

[0036] The flexible sensing element includes a flexible substrate layer and a sensing electrode array layer, wherein the sensing electrode array layer is printed on one side of the flexible substrate layer.

[0037] Based on the above technical solution, the preparation method and electrochemical sensing device of this application have at least the following beneficial technical effects:

[0038] The preparation method of this application involves using a fully automated screen printing machine to print multiple sensing electrode array layers on a flexible substrate according to the design of the model, forming multiple flexible sensing elements. Each flexible sensing element is then cut and wound into a cylindrical shape, heat-shrinked with heat-shrink tubing, and assembled into a sampling tip. The sampling tip, suction device, micro-electrochemical workstation, and signal processing equipment are then connected and assembled into an electrochemical sensing device. The electrochemical sensing device manufactured by this method has a simple structure, is easy to operate, and allows for easy mass production.

[0039] The electrochemical sensing device of this application utilizes a cylindrical flexible sensing element and a heat-shrink tubing to form a sampling tip. The sensing electrode array layer of the flexible sensing element is located on its inner wall, and the flexible sensing element is attached to the inner wall of the heat-shrink tubing. This allows the sensing electrode array layer of the sampling tip to form a tubular interface. The tubular interface has a large contact area with the droplet, which can significantly improve liquid utilization. On the other hand, the electrocatalytic interface area can be adjusted by changing the sample amount, expanding the effective sensing area, thereby flexibly adjusting the sample sensitivity and concentration. Furthermore, the tubular interface helps to form a closed detection environment, reducing liquid evaporation and making it less susceptible to interference from the external environment, thus improving the accuracy of the detection data. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A flowchart illustrating the fabrication method of the electrochemical sensing device provided in the embodiments of this application;

[0042] Figure 2 This is a flowchart of the printing screen design in the preparation method of the electrochemical sensing device provided in the embodiments of this application;

[0043] Figure 3 This is a flowchart of the printing process of multiple flexible sensing elements in the fabrication method of the electrochemical sensing device provided in this application embodiment;

[0044] Figure 4 This is a flowchart of the printing process of a single flexible sensing element in the fabrication method of the electrochemical sensing device provided in this application embodiment;

[0045] Figure 5 This is a flowchart illustrating the preparation process of the sampling pipette tip in the electrochemical sensing device provided in this application embodiment;

[0046] Figure 6 This is a schematic diagram of the structure of the electrochemical sensor provided in the embodiments of this application;

[0047] Figure 7 This is a three-dimensional structural schematic diagram of the sampling pipette in the electrochemical sensing device provided in the embodiments of this application;

[0048] Figure 8 This is a schematic diagram of the structure of the flexible sensing element of the sampling pipette tip in the electrochemical sensing device provided in the embodiments of this application.

[0049] In the figure, the following labels are used: 11-outer frame printing hole; 12-electrode lead printing hole; 13-insulating layer printing hole; 14-working electrode and counter electrode printing hole; 15-reference electrode printing hole; 100-flexible sensing element; 101-lead connection point; 102-electrode lead; 103-working electrode; 104-counter electrode; 105-reference electrode; 106-flexible substrate layer; 107-insulating layer; 108-outer frame; 200-sampling element; 201-support part; 202-sampling part; 300-attraction device; 400-micro electrochemical workstation; 500-signal processing equipment; 600-mold; 700-heat shrink tubing. Detailed Implementation

[0050] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0051] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0052] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0053] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0054] The technical solution of this application will be described in detail below with reference to the accompanying drawings.

[0055] Example 1

[0056] Please see Figure 1 This application provides a method for preparing an electrochemical sensing device, comprising the following steps:

[0057] Step S1: Design a model of the flexible sensing element 100 using modeling software, and design and manufacture a printing screen based on the model.

[0058] Specifically, this step also includes: fabricating a frame mesh, an electrode lead mesh, an insulating layer mesh, a working electrode mesh, a counter electrode mesh, and a reference electrode mesh based on the flexible sensing element model. The frame mesh has printed holes for the outer frame of each flexible sensing element 100; the electrode lead mesh has printed holes for electrode leads and lead connection points; the insulating layer mesh has printed holes for the insulating layer; the working electrode and counter electrode meshes have printed holes for the working electrode and counter electrode; and the reference electrode mesh has printed holes for the reference electrode.

[0059] In some embodiments, each printing screen has printing holes for printing multiple flexible sensing elements 100. For example, the frame line screen has outer frame line printing holes 11 for printing the outer frame lines of multiple flexible sensing elements 100. The electrode lead screen has electrode lead printing holes 12 for printing the electrode leads and lead connection points of multiple flexible sensing elements 100. The insulating layer screen has insulating layer printing holes 13 for printing the insulating layers of multiple flexible sensing elements 100. The working electrode and counter electrode screen has working electrode and counter electrode printing holes 14 for printing the working electrodes and counter electrodes of multiple flexible sensing elements 100. The reference electrode screen has reference electrode printing holes 15 for printing the reference electrodes of multiple flexible sensing elements 100. The printing hole structure for each flexible sensing element can be found in [reference needed]. Figure 2 .

[0060] Understandably, the frame stencil is used to print the outer frame 108 of each flexible sensing element 100 on the flexible substrate 106. The electrode lead stencil is used to print the electrode leads 102 and lead connection points 101. The insulating layer stencil is used to print the insulating layer 107. The working electrode and counter electrode stencils are used to print the working electrode 103 and the counter electrode 104. The reference electrode stencil is used to print the reference electrode 105.

[0061] Step S2: Prepare the printing material for the flexible sensing element 100; wherein the printing material includes a flexible substrate material and a printing paste.

[0062] In some embodiments, the flexible substrate material includes a polyimide film.

[0063] The flexible substrate layer of this application is made of polyimide film, which makes the electrode more flexible, thereby improving the adhesion between the flexible sensing element and the heat shrink tubing.

[0064] In some embodiments, the thickness of the polyimide film is 0.05 to 0.075 mm. If the polyimide film is too thin, it is not easy to seamlessly bond with the heat shrink tubing; if it is too thick, it is not easy to roll it into a cylindrical structure. Therefore, the thickness of the polyimide film used in this application is 0.05 mm to 0.075 mm.

[0065] In some embodiments, the printing paste includes insulating ink, conductive silver paste, silver chloride paste, carbon paste ink, and carbon nanotube paste. Specifically, carbon paste ink and carbon nanotube paste are used for printing the working electrode and the counter electrode to ensure strong electrochemical signals and good repeatability and stability of the printed electrodes. Silver chloride paste is used as the printing material for the reference electrode.

[0066] Step S3: Using a fully automatic screen printing machine, print multiple sensing electrode array layers on a flexible substrate layer according to the design of the model and use a printing screen to form multiple flexible sensing elements.

[0067] Please see Figure 2 , Figure 3 and Figure 4 , Figure 3 and Figure 4 The following diagrams illustrate the printing process of multiple flexible sensing elements and a single flexible sensing element in the fabrication method of the electrochemical sensing device provided in this application. Specifically, the fabrication process of the flexible sensing element 100 further includes the following steps:

[0068] Step 1: Using a frame stencil, insulating ink is printed on the surface of the flexible substrate 106 to form the outer frame 108 of each flexible sensing element 100;

[0069] Step 2: Using an electrode lead mesh, conductive silver paste is printed inside the outer frame 108 of each flexible sensing element 100 to form electrode leads 102 and lead connection points 101;

[0070] Step 3: Using an insulating stencil, insulating ink is printed over the electrode leads 102 of each flexible sensing element 100 to form an insulating layer 107;

[0071] Step 4: Using the working electrode and counter electrode stencils, carbon paste ink and carbon nanotube paste are printed on the exposed portion of the insulating layer 107 of each flexible sensing element 100 to form the working electrode 103 and the counter electrode 104.

[0072] Step 5: Using a reference electrode stencil, silver chloride paste is printed onto the exposed portion of the insulating layer 107 of each flexible sensing element 100 to form a reference electrode 105.

[0073] This allows for the printing of multiple sensing electrode array layers in batches on the flexible substrate 106. The printing process for each sensing electrode array layer is as follows: Figure 4 As shown, after printing, the flexible sensing element 100 is cut along the outer frame, which makes it easy to mass-produce.

[0074] In some embodiments, after each layer of screen printing is completed, it is placed in an oven and dried at 70℃~80℃ for 15min~20min. Each layer of screen can be printed 2~3 times. The printing speed can be 180mm / s~230mm / s, and can be adjusted according to the viscosity of the printing paste. The printing pressure can be 50N~70N. If the squeegee pressure is too high, it will easily damage the screen; if the pressure is too low, the printing effect will be poor or the screen will stick. The screen spacing is (-900~-1300)μm. If the spacing is too small, it will easily stick to the screen or be blurry; if it is too large, it will easily lead to poor printing and damage to the screen.

[0075] Step S4: Cut a single flexible sensing element 100, and roll the cut flexible sensing element 100 into a cylindrical structure with the sensing electrode array layer on the inside. Place the heat shrink tube 700 on the outside of the flexible sensing element 100 and heat shrink it so that the flexible sensing element 100 is attached to the inner wall of the heat shrink tube 700 around the circumference, and assemble it into a sampling tip.

[0076] In some specific embodiments, see [link to specific examples]. Figure 5 , Figure 5 A flowchart illustrating the fabrication process of the sampling pipette tip in the electrochemical sensing device provided in this application embodiment is shown; the fabrication process of the sampling pipette tip further includes the following steps:

[0077] Step ①: Wind the flexible sensing element 100 and place the sensing electrode array layer on the inner wall of the flexible sensing element 100;

[0078] Step 2: Nest the mold 600 inside the flexible sensing element 100.

[0079] Step 3: Nest a heat shrink tubing 700 around the flexible sensing element 100.

[0080] Step 4: Heat shrink; and stretch the lower end of the heat shrink tubing into a cone shape by stress.

[0081] In this step, the heat shrink temperature is 110℃~120℃, and the heat shrink time is 40s~80s. If the temperature is too low, the heat shrink tubing will not be able to fully adhere to the flexible sensing element; if the temperature is too high, it will cause excessive heat shrinkage and fail to match the aperture of the suction device.

[0082] Step 5: Remove the internal mold 600 to form the sampling nozzle.

[0083] In some embodiments, the heat-shrink tubing 700, after heat shrinking, forms a sampling element 200. The sampling element 200 includes an upper support portion 201 and a lower sampling portion 202. The support portion 201 is cylindrical, and the sampling portion 202 is conical. The sampling element 200 is used to sample the liquid sample to be tested. The sample to be tested is drawn in through the sampling portion 202, allowing the liquid to enter and contact the sensing electrode array of the internal flexible sensing element. In another embodiment of this application, the aperture of the support portion 201 is 5mm to 6mm, and a suction port with an aperture of 2mm to 3mm is provided at the smaller end of the sampling portion 202. A suitable aperture allows the sampling tip to be tightly connected to the suction device and the flexible sensing element 100, forming a closed system, reducing liquid evaporation, and minimizing interference from the external environment, thereby improving the accuracy of the detection data.

[0084] Step S5: Connect and assemble the sampling tip, suction device 300, micro electrochemical workstation 400 and signal processing equipment 500 into an electrochemical sensing device.

[0085] Please see Figure 6 The sampling tip is detachably connected to the lower end of the suction device 300. The upper part of the sampling tip is connected to the micro electrochemical workstation 400 via a conductive connecting wire, which can be a wire or a conductive strip, to achieve electrical connection between the electrode leads of the sampling tip and external equipment. The micro electrochemical workstation 400 is detachably located in the middle of the suction device 300 and is communicatively connected to the signal processing device 500.

[0086] In some embodiments, the suction device 300 can be a pipette or a syringe. The signal processing device 500 can be a laptop, tablet, or smartphone. The communication connection can be wired or wireless. The wireless connection can be Bluetooth, infrared, cellular (mobile phone) wireless, or Wi-Fi, etc.

[0087] A complete electrochemical sensing device is assembled from an aspiration device 300, a sampling tip, a micro electrochemical workstation 400, and a signal processing device 500. This electrochemical sensing device can be a handheld integrated device with a simple structure and easy operation. The entire device can achieve semi-automation-single-hand operation.

[0088] Example 2

[0089] Please see Figure 6 , Figure 6 A three-dimensional structural schematic diagram of an electrochemical sensing device according to an embodiment of this application is shown. The electrochemical sensing device is prepared by the preparation method described in Example 1.

[0090] The electrochemical sensing device includes an attraction device 300, a micro-electrochemical workstation 400, a signal processing device 500, and a sampling tip. The sampling tip is detachably mounted at the lower end of the attraction device 300 and is connected to the micro-electrochemical workstation 400 via conductive connecting wires. The micro-electrochemical workstation 400 is detachably mounted in the middle of the attraction device 300 and is communicatively connected to the signal processing device 500. The conductive connecting wires can be wires or conductive adhesive strips, used to achieve electrical connection between the electrode leads of the sampling tip and external devices.

[0091] In some embodiments, the suction device 300 can be a pipette or a syringe. The signal processing device 500 can be a laptop, tablet, or smartphone. The communication connection can be wired or wireless. The wireless connection can be Bluetooth, infrared, cellular (mobile phone) wireless, or Wi-Fi, etc.

[0092] Please see Figure 7 , Figure 7 A schematic diagram of the sampling tip according to an embodiment of this application is shown. The sampling tip includes a sampling element 200 and a flexible sensing element 100. The flexible sensing element 100 is wound into a cylindrical structure, and a sensing electrode array layer is printed on the inner wall of the cylindrical flexible sensing element 100. The sampling element 200 is sleeved on the outer side of the flexible sensing element 100, and the flexible sensing element 100 is attached to the inner wall of the sampling element 200 circumferentially around the sampling element 200.

[0093] It is understood that the "outer side of the flexible sensing element 100" mentioned in this application refers to the side of the flexible sensing element away from the sensing electrode array layer, and can also be understood as the outer wall side of the cylindrical flexible sensing element. The "attachment" mentioned in this application refers to the outer side of the cylindrical structure of the flexible sensing element being attached to the inner wall of the sampling element.

[0094] The sampling tip of this application has a simple structure, is easy to operate, and is easy to mass-produce. The sampling tip of this application employs a flexible sensing element, which is wound into a cylindrical structure and attached to the inner wall of the sampling element. This allows the sensing electrode array layer printed on the inner wall of the flexible sensing element to form a tubular interface. The tubular interface has a large contact area with the droplet, which can significantly improve liquid utilization. Furthermore, the tubular interface helps to form a sealed detection environment, reducing liquid evaporation and making it less susceptible to interference from the external environment.

[0095] In another embodiment of this application, see [reference] Figure 7 The flexible sensing element 100 includes a flexible substrate 106 and a sensing electrode array layer, wherein the sensing electrode array layer is printed on one side of the flexible substrate 106.

[0096] It is understood that the sensing electrode array layer is formed on one side of the flexible substrate 106 by printing. The "one side" of the flexible substrate 106 mentioned in this application refers to one surface of the flexible substrate.

[0097] In this embodiment, the sensing electrode array layer is printed on one side of a flexible substrate, thereby making the entire flexible sensing element flexible and easy to roll into a cylindrical structure.

[0098] In another embodiment of this application, see [reference] Figure 8 The sensing electrode array layer includes electrode leads 102, lead connection points 101, an insulating layer 107, and electrode units. The electrode leads 102 and lead connection points 101 are printed on the surface of the flexible substrate layer 106. One end of the electrode lead 102 is connected to the lead connection point 101, which is connected to a wire and then to a micro-electrochemical workstation 400 via a wire adhesive strip, thus achieving electrical connection between the electrode unit and the micro-electrochemical workstation 400. The other end of the electrode lead 102 is connected to the electrode unit, and the insulating layer 107 covers the electrode leads 102.

[0099] In the sensing electrode array layer of this application embodiment, the lead connection point 101 and the electrode unit correspond one-to-one. The lead connection point 101 and the electrode unit are connected by the electrode lead 102. The lead connection point 101 is used to connect conductive connecting wires, such as wires or conductive strips. The insulating layer 107 covers the electrode lead 102, while the lead connection point 101 and the electrode unit are exposed to the outside.

[0100] In another embodiment of this application, the electrode unit includes a working electrode 103, a reference electrode 105, and a counter electrode 104. The working electrode 103 comprises three electrodes arranged side-by-side. Since multiple working electrodes 103 are printed inside the sensing electrode array layer, it can be used for simultaneous monitoring of multiple substances. That is, by inhaling a sample solution once, multiple electrochemical signals can be output simultaneously. For example, in the biomedical field, it can be used for simultaneous monitoring of multiple liver / kidney function indicators, simultaneous monitoring of antibiotic blood concentrations and prognostic biochemical indicators, etc.

[0101] The printing materials for the working electrode and the counter electrode in this application can be carbon paste ink and carbon nanotube paste (carbon nanotubes are 14 wt% by mass), and the printing material for the reference electrode can be silver chloride paste.

[0102] In another embodiment of this application, the electrode unit of the sensing electrode array layer described in this application includes three working electrodes, a reference electrode 105, and a counter electrode 104.

[0103] In another embodiment of this application, the flexible substrate 106 is a polyimide film.

[0104] In another embodiment of this application, the flexible substrate 106 may be transparent.

[0105] In another embodiment of this application, the thickness of the flexible substrate 106 is 0.05 to 0.075 mm.

[0106] In this embodiment, the thickness of the flexible substrate layer is 0.05–0.075 mm, which allows the flexible sensing element 100 to be easily and tightly bonded to the sampling element 200, and also makes it easy to roll the flexible sensing element 100 into a cylindrical structure. If the flexible substrate layer is too thin, it will not be easy to fit seamlessly with the sampling element 200; if it is too thick, it will not be easy to roll into a cylindrical structure.

[0107] In another embodiment of this application, see [reference] Figure 6The sampling element 200 includes a support portion 201 and a sampling portion 202. The support portion 201 is cylindrical, and the sampling portion 202 is conical. The large end of the sampling portion 202 is connected to the support portion 201, and the small end of the sampling portion 202 extends away from the support portion 201. The flexible sensing element 100 is attached to the inner wall of the support portion 201 around the circumference of the support portion.

[0108] The sampling element 200 is a part used to sample the liquid sample to be tested. The sampling part 202 draws in the sample to be tested, allowing the liquid to enter and contact the electrode unit of the flexible sensing element inside.

[0109] In another embodiment of this application, the sampling element 200 is formed by heating and shrinking a transparent heat-shrink tubing 700.

[0110] In another embodiment of this application, the support portion 201 has an aperture of 5mm to 6mm, and a suction port with an aperture of 2mm to 3mm is provided at the small end of the sampling portion 202.

[0111] In the embodiments of this application, the aperture of the support portion of the sampling element can be tightly connected with the suction device and the sensing sampling element to form a closed system, which can reduce the evaporation of liquid and is not affected by the external environment.

[0112] A complete electrochemical sensing device is assembled by combining an aspiration device 300, a sampling tip, a micro electrochemical workstation 400, and a signal processing device 500.

[0113] The electrochemical sensing device of this application has a simple structure, which is easy to mass-produce. At the same time, the electrode unit integrated in the sampling tip has a high liquid utilization rate and can adjust the electrocatalytic interface area by changing the sample amount, thereby flexibly adjusting the sample sensitivity and concentration.

[0114] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing an electrochemical sensing device, characterized in that, Includes the following steps: Models of flexible sensing elements are designed using modeling software, and printed stencils are designed and fabricated based on these models. Prepare printing materials for flexible sensing elements; wherein, the printing materials include flexible substrate material and printing paste; The printing material is designed according to the model using a fully automatic screen printing machine, and multiple sensing electrode array layers are printed on a flexible substrate using the printing screen to form multiple flexible sensing elements. A single flexible sensing element is cut, and the cut flexible sensing element is wound into a cylindrical structure with the sensing electrode array layer on the inside. A heat shrink tube is placed on the outside of the flexible sensing element and heated to shrink it, so that the flexible sensing element is attached to the inner wall of the heat shrink tube around the circumference of the heat shrink tube, and assembled into a sampling tip. The sampling tip, suction device, micro electrochemical workstation, and signal processing equipment are connected and assembled into an electrochemical sensing device.

2. The preparation method according to claim 1, characterized in that, The steps of designing a model of the flexible sensing element using modeling software and designing and fabricating a printing screen based on the model further include: Based on the model of flexible sensing element, frame wire mesh, electrode lead mesh, insulating layer mesh, working electrode and counter electrode mesh, and reference electrode mesh were fabricated respectively. The frame mesh plate has printed holes for the outer frame of each flexible sensing element, the electrode lead mesh plate has printed holes for the electrode leads and lead connection points, the insulating layer mesh plate has printed holes for the insulating layer, the working electrode and counter electrode mesh plates have printed holes for the working electrode and counter electrode, and the reference electrode mesh plate has printed holes for the reference electrode.

3. The preparation method according to claim 2, characterized in that, In the step of preparing the printing material for the flexible sensing element, the flexible substrate material includes a polyimide film, and the printing paste includes insulating ink, conductive silver paste, silver chloride paste, carbon paste ink, and carbon nanotube paste.

4. The preparation method according to claim 3, characterized in that, The thickness of the polyimide film is 0.05 to 0.075 mm.

5. The preparation method according to claim 4, characterized in that, The step of using a fully automatic screen printing machine to print the printing material according to the model design and using the printing screen to print multiple sensing electrode array layers on a flexible substrate to form multiple flexible sensing elements further includes: Insulating ink is printed on the surface of the flexible substrate using the frame mesh to form the outer frame of each flexible sensing element; Conductive silver paste is printed inside the outer frame of each flexible sensing element using the electrode lead mesh to form electrode leads and lead connection points. Insulating ink is printed above the electrode leads of each flexible sensing element using the insulating mesh to form an insulating layer; The working electrode and the counter electrode are formed by printing carbon paste ink and carbon nanotube paste on the insulating layer of each flexible sensing element using the aforementioned working electrode and counter electrode stencils. The reference electrode is formed by printing silver chloride paste onto the insulating layer of each flexible sensing element using the reference electrode stencil.

6. The preparation method according to claim 5, characterized in that, The step of using a fully automatic screen printing machine to print the printing material according to the model design and using the printing screen to print multiple sensing electrode array layers on a flexible substrate to form multiple flexible sensing elements further includes: After each layer of screen printing is completed, it is placed in an oven and dried at 70℃~80℃ for 15min~20min.

7. The preparation method according to claim 6, characterized in that, The steps of cutting a single flexible sensing element, winding the cut flexible sensing element into a cylindrical structure with the sensing electrode array layer on the inside, and then heat-shrinking a heat-shrink tubing over the outside of the flexible sensing element so that the flexible sensing element is circumferentially attached to the inner wall of the heat-shrink tubing to assemble the sampling tip further include: The flexible sensing element is wound up, and the sensing electrode array layer is located on the inner wall of the flexible sensing element. A mold is nested inside the flexible sensing element; A heat shrink tubing is nested outside the flexible sensing element; Heat shrinks the tube; and stretches it into a cone shape at the lower end by stress. Remove the internal mold.

8. The preparation method according to claim 7, characterized in that, During heat shrinking, the heat shrinking temperature is 110℃~120℃, and the heat shrinking time is 40s~80s.

9. An electrochemical sensing device, characterized in that, The electrochemical sensing device is prepared by the preparation method according to any one of claims 1 to 8. The electrochemical sensing device includes an attraction device, a micro electrochemical workstation, a signal processing device, and a sampling tip. The sampling tip is detachably disposed at the lower end of the attraction device. The sampling tip is connected to the micro electrochemical workstation via a conductive connecting wire. The micro electrochemical workstation is detachably disposed in the middle of the attraction device. The micro electrochemical workstation is communicatively connected to the signal processing device.

10. The electrochemical sensing device according to claim 9, characterized in that, The sampling tip includes a sampling element and a flexible sensing element. The flexible sensing element is wound into a cylindrical structure, and a sensing electrode array layer is printed on the inner wall of the cylindrical flexible sensing element. The sampling element is sleeved on the outside of the flexible sensing element, and the flexible sensing element is attached to the inner wall of the sampling element circumferentially around the sampling element. The flexible sensing element includes a flexible substrate layer and a sensing electrode array layer, wherein the sensing electrode array layer is printed on one side of the flexible substrate layer.

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