Potassium detection test paper, preparation method, potassium detection device and working method

Abstract

The present application relates to blood potassium detection test paper, preparation method and blood potassium detection device and working method belong to blood potassium detection technical field, solve the defects existing in current detection device, including the base, the middle layer, the blood cell filter layer and the hydrophobic layer which are arranged in turn, further including working electrode, reference electrode and thermistor, the working electrode, the reference electrode and the thermistor are installed on the base through the first groove of the base, and the first flexible pad layer is arranged between the working electrode, the reference electrode, the thermistor and the bottom groove surface of the first groove, the second flexible pad layer is arranged between the working electrode, the reference electrode, the thermistor and the middle layer, the cavity above the detection part of the working electrode, the reference electrode and the thermistor is arranged on the bottom surface of the middle layer, the middle layer and the hydrophobic layer are provided with blood flow channel, and the blood flow channel is communicated with the cavity, and the test paper of the application realizes quantitative and accurate detection of blood potassium concentration.

Description

Technical Field

[0001] This invention relates to the field of blood potassium detection technology, specifically to blood potassium test strips, preparation methods, blood potassium detection devices, and working methods. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Serum potassium concentration, as a key electrolyte indicator for maintaining neuromuscular excitability, myocardial function, and cellular metabolic balance, has irreplaceable value in clinical diagnosis and treatment. Whether dealing with acute severe conditions such as arrhythmias and diabetic ketoacidosis, or conducting long-term medication monitoring for patients with chronic kidney disease, heart failure, and hypertension, rapid and accurate serum potassium data directly affect the safety and effectiveness of medical decisions.

[0004] Patent CN211955502U discloses a test strip for detecting blood potassium, comprising a reaction base layer, a reaction layer, a blood filtration layer, a capillary injection layer, and a hydrophilic layer stacked sequentially. The outermost layer of this test strip is a hydrophilic layer, meaning that external moisture and contamination can affect its accuracy. Furthermore, this test strip detects target analytes through a colorimetric reaction, resulting in low accuracy in quantitative analysis.

[0005] Patent application CN120267284A discloses a portable bedside potassium analyzer that corrects circuit drift solely through an ambient temperature sensor, neglecting the difference in initial temperature of the blood sample itself (such as the difference between hypothermic peripheral blood and blood samples from febrile patients). Since ion-selective electrode reactions follow the Nernst equation, temperature directly affects the electrode response slope; furthermore, there is a heat transfer hysteresis effect after a small amount of blood sample is added. If it is assumed that the sample is instantly in equilibrium with the environment, the actual reaction temperature at the detection interface will not match the preset value, resulting in underestimation of high values ​​or overestimation of low values, which can seriously mislead emergency decisions. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a blood potassium test strip, a preparation method, a blood potassium detection device, and a working method. The test strip can achieve quantitative detection with high accuracy, and the detection device can take into account the influence of blood temperature, thus improving the accuracy of the detection.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, embodiments of the present invention provide a blood potassium test strip, comprising a substrate, an intermediate layer, a blood cell filter layer, and a hydrophobic layer stacked sequentially, and further comprising a working electrode, a reference electrode, and a thermistor. The working electrode, reference electrode, and thermistor are mounted on the substrate through a first groove provided in the substrate, and a first flexible pad is provided between the working electrode, reference electrode, and thermistor and the bottom groove surface of the first groove. A second flexible pad is provided between the working electrode, reference electrode, and thermistor and the intermediate layer, and the second flexible pad exposes the detection portion of the working electrode, reference electrode, and thermistor. A cavity is formed on the bottom surface of the intermediate layer above the detection portion of the working electrode, reference electrode, and thermistor. Blood channels are formed in the intermediate layer and the hydrophobic layer, and the blood channels communicate with the cavity. The blood channels pass through the blood cell filter layer to filter blood cells through the blood cell filter layer.

[0008] Optionally, the bottom surface of the intermediate layer is provided with a second groove, and the second flexible pad layer is located inside the second groove.

[0009] Optionally, the hydrophobic layer is provided with a plurality of first capillary channels, one end of which extends to the side of the hydrophobic layer and the other end is connected to a first blood groove provided on the bottom surface of the hydrophobic layer. The top surface of the intermediate layer is provided with a second blood groove corresponding to the first blood groove. The second blood groove is connected to one end of a plurality of second capillary channels, and the other end of the second capillary channels is connected to the cavity. The first capillary channel, the first blood groove, the second blood groove, and the third capillary channel constitute the blood flow channel. A blood cell filtration layer is provided between the first blood groove and the second blood groove.

[0010] Optionally, both the hydrophobic layer and the intermediate layer are made of hydrophobic plastic film.

[0011] Optionally, the blood cell filtration layer is made of a polymer fiber membrane that allows plasma to pass through while preventing blood cells from passing through.

[0012] Optionally, both the first flexible pad and the second flexible pad are made of Teflon film.

[0013] Secondly, embodiments of the present invention provide a method for preparing the blood potassium test strip described in the first aspect, comprising the following steps: After preparing a first flexible pad on the bottom surface of the first groove of the substrate, a working electrode, a reference electrode and a thermistor are prepared inside the first groove. A sensitive film is fabricated on the surface of the detection portion of the working electrode; The intermediate layer and the blood cell filtration layer are bonded and fixed, and a second flexible pad is prepared in the region of the intermediate layer corresponding to the working electrode, the reference electrode and the thermistor to form an intermediate layer-blood cell filtration layer composite membrane. The intermediate layer-blood cell filtration layer composite membrane is stacked on the upper surface of the substrate, and the hydrophobic layer is stacked on the upper surface of the intermediate layer-blood cell filtration layer composite membrane. The hydrophobic layer, the intermediate layer-blood cell filtration layer composite membrane and the substrate are fixed by hot pressing.

[0014] Thirdly, embodiments of the present invention provide a blood potassium detection device, including a blood potassium detector and the blood potassium test strip described in the first aspect. The blood potassium detector includes a housing, the housing is provided with a socket that matches the blood potassium test strip, the socket is provided with an interface corresponding to the working electrode, the reference electrode and the thermistor, the interface is connected to a data acquisition module installed inside the housing, and the data acquisition module is connected to a data processing module.

[0015] Fourthly, embodiments of the present invention provide a method for detecting blood potassium, using the blood potassium detection device described in the third aspect, comprising the following steps: The potential information and current blood temperature information are obtained after the blood to be tested passes through the blood cell filter layer, falls through the cavity to the working electrode, reference electrode and the thermistor detection part. The actual slope of the Nernst equation at the current blood temperature is obtained by combining the current blood temperature information with a pre-established temperature-Nernst equation slope relationship model. The Nernst equations were corrected using the actual slopes obtained. The blood potassium concentration is obtained based on the acquired potential information and the modified Nernst equation.

[0016] Optionally, the method for establishing the temperature-Nernst equation slope relationship model includes the following steps: Step 1: Obtain the response potential of different concentrations of serum potassium standard solutions at the current temperature; Step 2: Fit the concentrations of different serum potassium standard solutions and their corresponding response potentials using the least squares method to obtain the slope of the Nernst equation at the current temperature; Step 3: Repeat steps 1-2 to obtain the slope of the Nernst equation corresponding to blood potassium standard solutions at different temperatures; Step 4: Fit the blood potassium standard solutions at different temperatures and their corresponding slopes from Step 3 to obtain the temperature-Nernst equation slope relationship model.

[0017] The beneficial effects of this invention are as follows: 1. The test strip of the present invention has an outermost hydrophobic layer, allowing only blood to flow into the flow channel. External moisture and contaminants will not affect the detection accuracy, ensuring the accuracy of the test results. Moreover, the detection of blood potassium is achieved by using the potential signals generated after the reference electrode and working electrode fall into the blood. Compared with detection by colorimetric reaction, it can achieve quantitative detection of blood potassium concentration with high accuracy. Since the test strip is formed by hot pressing, the groove, the first flexible pad, and the second flexible pad protect the working electrode, the reference electrode, and the thermistor during the hot pressing process, avoiding stress concentration problems of the electrodes and thermistors. This prevents the electrodes and thermistors from delaminating and peeling off from the substrate, allowing the electrodes and thermistors to be used in test strips using the hot pressing process, thus improving the yield of the test strip.

[0018] 2. In the blood potassium detection device and method of the present invention, the cavity is set above the detection part of the thermistor. Therefore, the thermistor can directly collect the temperature value of the blood, instead of collecting the ambient temperature and assuming that the ambient temperature and blood temperature are instantly balanced. This ensures that the temperature collected during detection matches the actual reaction temperature and ensures the accuracy of the detection results. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 This is an exploded view of the overall structure of Embodiment 1 of the present invention; Figure 2 This is a cross-sectional view of the overall structure of Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the distribution of the working electrode, reference electrode, and thermistor on the substrate in Embodiment 1 of the present invention; Figure 4 This is a flowchart of the test strip preparation process according to Embodiment 2 of the present invention; Figure 5 This is a front view of the blood potassium analyzer of Embodiment 3 of the present invention; Figure 6 This is a top view of the blood potassium analyzer of Embodiment 3 of the present invention; Figure 7 This is a bottom view of the blood potassium analyzer of Embodiment 3 of the present invention; Figure 8 This is a schematic diagram of the blood potassium analyzer in Embodiment 3 of the present invention. Among them, 1. Display screen, 2. Function button one, 3. Function button two, 4. Port, 5. Type-C power supply port; 601. Hydrophobic layer, 602. Intermediate layer, 603. Thermistor, 604. Working electrode, 605. Reference electrode, 606. Substrate, 607. Blood cell filtration layer, 608. Second flexible pad, 609. First flexible pad. Detailed Implementation

[0021] For ease of description, the words "upper" and "lower" appearing in this invention only indicate that they are consistent with the upper and lower directions of the accompanying drawings and do not limit the structure. They are merely for the purpose of facilitating the description of this invention and simplifying the description, and do not indicate or imply that the device or component 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 the invention.

[0022] Example 1 This embodiment provides a blood potassium test strip, such as Figures 1-3 As shown, a layered structure is adopted, including a substrate 606, an intermediate layer 602, a blood cell filtration layer 607 and a hydrophobic layer 601 stacked from bottom to top. A working electrode 604, a reference electrode 605 and a thermistor 603 are provided between the substrate 606 and the intermediate layer 602.

[0023] The hydrophobic layer 601 is made of plastic film. Preferably, the hydrophobic layer 601 is made of PVC film with a thickness of 0.7 mm. The hydrophobic layer 601 is processed with multiple first capillary channels by a mold forming method. One end of the first capillary channel extends to the side of the hydrophobic layer 601, and the other end is connected to the first blood groove opened on the bottom surface of the hydrophobic layer 601.

[0024] The first capillary channel guides the flow of blood, allowing it to enter the first blood tank.

[0025] The processing method for the hydrophobic layer 601 can be achieved using existing technology, and will not be described in detail here.

[0026] The intermediate layer 602 is made of the same material as the hydrophobic layer 601, and is also made of plastic film. Preferably, it is made of PVC film with a thickness of 0.7 mm. The intermediate layer 602 is processed with multiple second capillary channels by a mold forming method. One end of the second capillary channel is connected to the second blood groove opened on the top surface of the intermediate layer 602, and the other end is connected to the cavity opened on the bottom surface of the intermediate layer 602.

[0027] The second capillary channel guides blood flow, allowing blood to flow from the second blood groove into the cavity.

[0028] The processing method for the intermediate layer 602 can be achieved using existing technology, and will not be described in detail here.

[0029] The first blood groove and the second blood groove correspond to each other, so that the first capillary channel, the first blood groove, the second blood groove and the second capillary channel together constitute a blood flow channel communicating with the cavity.

[0030] The blood cell filtration layer 607 is disposed between the intermediate layer 602 and the hydrophobic layer 601, thereby enabling the blood cell filtration layer 607 to be disposed between the first blood groove and the second blood groove to achieve the filtration of blood cells in the blood.

[0031] In this embodiment, the volume of the first blood groove and the second blood groove is 15μL, and the cross-sections of the first capillary channel and the second capillary channel are both rectangular, with a length of 200μm and a depth of 100μm.

[0032] In this embodiment, the blood cell filter layer 607 is a polymer fiber membrane prepared by electrospinning. The polymer fiber membrane can effectively intercept and filter blood cells such as red blood cells and white blood cells in the blood, allowing plasma to pass through smoothly while blood cells cannot pass through smoothly, thereby achieving physical blood cell separation before detection and eliminating the need for centrifugation.

[0033] Preferably, the blood cell filtration layer 607 is made of polyacrylonitrile (PAN) nanofiber membrane with an average fiber diameter of about 500 nm, a porosity of >85%, and a thickness of about 100 μm.

[0034] The substrate 606 is made of PET plastic sheet, and preferably, the thickness of the substrate 606 is 0.5 mm.

[0035] The substrate 606 has a first groove, and the reference electrode, thermistor and working electrode are disposed inside the first groove of the substrate 606.

[0036] In this embodiment, three first grooves are provided. One first groove is matched with the reference electrode 605 and the reference electrode 605 is disposed therein. Another first groove is matched with the thermistor 603 and the thermistor 603 is disposed therein. The third first groove is matched with the working electrode 604 and the working electrode 604 is disposed therein.

[0037] A first flexible pad 609 is provided between the reference electrode 605, the thermistor 603 and the working electrode 604 and the bottom surface of the first groove.

[0038] In this embodiment, the first flexible pad 609 is made of a Teflon film that can withstand high temperatures.

[0039] Furthermore, four second grooves are provided on the bottom surface of the intermediate layer 602. The two second grooves on both sides correspond one-to-one with the first grooves corresponding to the reference electrode 605 and the working electrode 604, respectively. The two second grooves in the middle correspond to the first grooves corresponding to the thermistor 603. The bottom groove surface of each of the four second grooves is provided with a second flexible pad 608.

[0040] In this embodiment, the second flexible pad 608 is made of a Teflon film that can withstand high temperatures.

[0041] After the intermediate layer 602 is disposed on the upper surface of the substrate 606, a reference electrode 605 is disposed in the space formed by one set of first grooves and second grooves, a thermistor 603 is disposed in the space formed by another set of first grooves and second grooves, and a working electrode 604 is disposed in the space formed by a third set of first grooves and second grooves.

[0042] A first flexible pad 609 is provided below the working electrode 604, the reference electrode 605 and the thermistor 603, and a second flexible pad 608 is provided above them.

[0043] The first flexible pad 609 below the working electrode covers the entire lower surface of the working electrode 604, the first flexible pad 609 below the reference electrode 605 covers the entire lower surface of the reference electrode, and the first flexible pad 609 below the thermistor 603 covers the entire lower surface of the thermistor 603.

[0044] The shape and size of the second flexible pad 608 are designed to expose the detection portions of the working electrode 604, the reference electrode 605, and the thermistor 603, such that the cavity opened on the bottom surface of the intermediate layer 602 is located directly above the detection portions of the working electrode 604, the reference electrode 605, and the thermistor 603.

[0045] The working electrode 604 is prepared in its corresponding first groove using a carbon paste screen printing process. After the carbon paste screen printing is completed, a 9-11 μm sensitive film is applied to the surface of the area corresponding to the printed structure and the detection part by a drop coating method. Preferably, a 10 μm sensitive film is applied.

[0046] The sensitive membrane is composed of the following components: 85 wt% PEDOT:PSS aqueous dispersion, 10 wt% plasticizer o-nitrophenyl octyl ether, 4.5 wt% potassium ion carrier valamicin and 0.5 wt% anion scavenger tetra(dodecyl)ammonium chloride.

[0047] The reference electrode 605 is screen-printed in the first groove using Ag or AgCl paste.

[0048] The thermistor 603 is made by screen printing Pt paste in the first groove.

[0049] The working electrode 604, the reference electrode 605, and the thermistor 603 all extend to the side of the substrate 606 to form contacts for connection with the data acquisition module.

[0050] Example 2 This embodiment provides a method for preparing the blood potassium test strip described in Embodiment 1, such as... Figure 4 As shown, it includes the following steps: Step S1: Create the 606 substrate.

[0051] The substrate 606 is an insulating PET substrate. The PET substrate with the first groove is made by molding using a pre-made template. Existing technology can be used for molding, so it will not be described in detail here.

[0052] Teflon material is coated on the bottom surface of the first groove and dried at 80°C for 5 minutes to form the first flexible pad 609.

[0053] Step S2: Screen printing of sensing electrodes.

[0054] The sensing electrode includes a working electrode 604, a reference electrode 605, and a thermistor 603, which are fabricated on a substrate 606.

[0055] A carbon electrode 604 is formed by printing carbon paste in a first groove using a screen printing machine, a reference electrode 605 is formed by printing Ag or AgCl in another first groove, and a thermistor 603 is formed by printing Pt paste in a third groove.

[0056] During the screen printing process, each layer is dried in an 80°C oven for 5 minutes after printing.

[0057] Using a micro-dispensing device, 3 μL of sensitive membrane slurry was drop-coated onto the surface of the detection portion of the working electrode 604. The composition of the sensitive membrane slurry was as follows: 85 wt% PEDOT:PSS aqueous dispersion, 10 wt% plasticizer o-nitrophenyl octyl ether, 4.5 wt% potassium ion carrier valamicin and 0.5 wt% anion scavenger tetra(dodecyl)ammonium chloride.

[0058] After coating the sensitive film slurry, the substrate 606, working electrode 604, reference electrode 605, and thermistor 603 are placed in a clean environment at 40°C and relative humidity <30% to cure and dry for 12 hours, forming a stable 10μm thick sensitive film on the surface of the detection part of the working electrode 604.

[0059] Step S3: Preparation of the intermediate layer-blood cell filtration layer composite membrane.

[0060] An intermediate layer 602 with a second capillary channel, a second blood groove, a cavity, and a second groove is prepared using a mold forming method. Pressure-sensitive adhesive is then applied to the upper surface of the intermediate layer 602, which is used to cooperate with the blood cell filtration layer 607.

[0061] The blood cell filter layer 607, which is produced by electrospinning, is cut to the target size. The blood cell filter layer 607 and the intermediate layer 602 are bonded and fixed with pressure-sensitive adhesive to form an intermediate layer-blood cell filter layer composite membrane.

[0062] Step S4: Hot pressing molding.

[0063] The substrate 606 prepared in step S2, which has a working electrode 604, a reference electrode 605 and a thermistor 603, is fixed. An intermediate layer-blood cell filter layer composite membrane is stacked on top of the substrate. A pre-formed hydrophobic layer 601 with a first blood groove and a first capillary channel is stacked on top of the intermediate layer-blood cell filter layer composite membrane to ensure that the positions of the first blood groove and the second blood groove correspond.

[0064] Using a hot press, the membrane is pressed at 90℃ and 0.5 MPa for 4-6 seconds, preferably 5 seconds, to firmly bond the substrate 606, the intermediate layer-blood cell filtration layer composite membrane, and the hydrophobic layer 601. The first capillary channel, the first blood groove, the blood cell filtration layer, the second blood groove, the second capillary channel, and the cavity form a continuous blood flow path. The first capillary channel, the first blood groove, the second blood groove, and the second capillary channel together constitute the blood flow channel communicating with the cavity.

[0065] In this embodiment, the heating rate is strictly controlled during hot pressing, and the heating rate is 3-5℃ / min.

[0066] During the hot pressing process, the pressure is initially borne by the material above the working electrode 604, reference electrode 605, and thermistor 603, preventing stress from directly acting on these components and causing damage. Simultaneously, the first flexible pad 609 and the second flexible pad 608 disperse the concentrated point pressure into surface pressure, effectively preventing breakage and detachment of the working electrode 604, reference electrode 605, and thermistor 603 due to stress concentration. In the hot pressing process, the heating rate (3-5℃ / min) is strictly controlled to allow for slow stress release. A flexible buffer film is placed on the surface of the imprinting mold, employing a sequence of contact, heating, and then pressure application to prevent damage to the working electrode 604, reference electrode 605, and thermistor 603 caused by hard pressing in a cold state.

[0067] The laminated material was cut into individual test strip units using a cutting machine, thus completing the preparation of the test strip. The total size of the prepared test strip is 5mm × 30mm × 2mm.

[0068] After being cut, the test strip units are placed in an aluminum foil bag in a nitrogen atmosphere, and a desiccant is added. After sealing, the finished test strip is obtained.

[0069] The blood potassium test strip and its preparation method in this embodiment have an outermost hydrophobic layer, allowing only blood to flow into the channel. External moisture and contaminants do not affect the detection accuracy, ensuring the accuracy of the test results. Furthermore, blood potassium is detected by the potential signal generated after the reference electrode 605 and working electrode 604 fall into the blood. Compared to detection via a colorimetric reaction, this method enables quantitative detection of blood potassium concentration with high accuracy. Because the test strip is formed using a hot-pressing process, the grooves, the first flexible pad 609, and... The second flexible pad 608 protects the working electrode 604, reference electrode 605, and thermistor 603 during the hot pressing process, avoiding stress concentration problems and thus preventing delamination and peeling of the working electrode 604, reference electrode 605, and thermistor 603 from the substrate 606. This allows the working electrode 604, reference electrode 605, and thermistor 603 to be used in test strips using the hot pressing process, improving the yield of the test strips.

[0070] Example 3 This embodiment provides a blood potassium detection device, including a blood potassium analyzer and the blood potassium test strip described in Embodiment 1, as follows: Figures 5-7 As shown, the blood potassium analyzer includes a housing made of ABS engineering plastic, measuring 120mm × 65mm × 20mm and weighing approximately 150g. One end of the housing has a socket 4 that matches the blood potassium test strip, allowing the blood potassium test strip to be inserted into the socket 4.

[0071] Inside the casing, there is also a two-layer PCB circuit board, such as Figure 8As shown, the PCB integrates a signal acquisition module, a power amplifier module, an analog-to-digital converter module, and an MCU module. The signal acquisition module is used to acquire the micro-current signal between the working electrode 604 and the reference electrode 605, as well as the potential signal of the thermistor 603. The signal acquisition module uses an operational amplifier with high input impedance and low bias current to form a constant potential circuit. Existing technology can be used for the signal acquisition module, which will not be described in detail here. The input terminal of the signal acquisition module has a gold-plated elastic contact located in the socket. The signal acquisition module can be connected to the working electrode 604, the reference electrode 605, and the thermistor 603 through the gold-plated elastic contact, thereby enabling the signal acquisition module to apply a stable excitation potential and acquire the micro-current signal between the working electrode 604 and the reference electrode 605, as well as the voltage signal output by the thermistor 603. Among them, the micro-current signal between the working electrode 604 and the reference electrode 605 serves as the detection signal, and the voltage signal output by the thermistor 603 serves as the temperature signal.

[0072] The power amplifier module is connected to the detection signal output terminal of the signal acquisition module. It is used to convert and amplify the acquired nanoampere-level microcurrent signal into a volt-level voltage signal. The power amplifier module can be an existing programmable gain instrumentation amplifier, which will not be described in detail here.

[0073] The analog-to-digital converter (ADC) module is connected to the temperature signal output terminals of the power amplifier module and the signal acquisition module. The ADC module digitizes the amplified analog signal and temperature signal from the power amplifier module. An existing 16-bit high-precision ADC chip can be used for the ADC module, which will not be described in detail here. In this embodiment, the sampling rate of the ADC module is 1 kSPS.

[0074] The analog-to-digital converter (ADC) module is connected to the MCU module, which uses a low-power ARM Cortex-M4 core microcontroller. The MCU module processes the received digital signal and outputs the final potassium ion concentration value.

[0075] The MCU module is connected to the display screen 1 located in the housing. The display screen is a 2.4-inch color LCD screen used to display the detection results on the 2.4-inch color LCD screen.

[0076] The housing also has function button 1 (on / off) and function button 2 (history record) for connecting to the MCU module. The top of the housing has a Type-C power supply port 5, which can be used to power the PCB circuit board using a power bank or mobile phone charger.

[0077] The settings for function button 1 (2), function button 2 (3), and Type-C power supply port 5 can be achieved using existing technology and will not be described in detail here.

[0078] Furthermore, the MCU module integrates an additional Bluetooth Low Energy (BLE) chip. The MCU module connects to the user terminal via the Bluetooth chip. The user terminal can be a smartphone, tablet, or dedicated data gateway, etc. The MCU module can transmit the detected blood potassium concentration value, detection timestamp, and other data to the user terminal via the Bluetooth chip.

[0079] The client comes with a corresponding application that has the following functions: Automatic data reception and storage: After the instrument completes the test, the data is automatically synchronized to the application program, forming a long-term, continuous personal blood potassium history database.

[0080] Trend analysis and chart display: The application generates blood potassium concentration change curves on a daily, weekly, and monthly basis, visually displaying the trend of blood potassium levels.

[0081] Abnormal alerts: Users can customize a safe range for blood potassium concentration (e.g., 3.5-5.0 mmol / L). When the test result exceeds this range, the application will immediately send a push notification to the user.

[0082] Report generation and sharing: The test data within a selected time period can be generated into a PDF report, which can be provided to doctors for reference when users consult doctors online or visit doctors.

[0083] Example 4 This embodiment provides a method for detecting blood potassium, which is performed using the blood potassium detection device described in Embodiment 3, and includes the following steps: turning on the power of the blood potassium detector, inserting a blood potassium test strip into the socket of the blood potassium detector, so that the reference electrode, working electrode and thermistor are connected to the signal acquisition module.

[0084] The user uses a lancet to collect a drop of capillary whole blood from the fingertip, and then contacts the fingertip with the side of the hydrophobic layer 601. The blood droplet enters the first capillary channel under the siphon effect of the first capillary channel. The blood flows sequentially through the first capillary channel, the first blood groove, the blood cell filter layer, the second blood groove, the second capillary channel, and the cavity before reaching the surface of the working electrode 604, the reference electrode 605, and the thermistor 603 detection part. The blood cell filter layer 607 filters the blood cells in the blood, so that only plasma reaches the surface of the working electrode 604, the reference electrode 605, and the thermistor 603 detection part.

[0085] At this time, the MCU module receives the potential between the reference electrode 605 and the working electrode 604 acquired by the signal acquisition module, as well as the current blood temperature information acquired by the thermistor 603.

[0086] The actual slope of the Nernst equation at the current blood temperature is obtained by combining the current blood temperature information with a pre-established temperature-Nernst equation slope relationship model.

[0087] The Nernst equation is:

[0088] Where E is the potential information received by the MCU module, E0 is the standard electrode potential, which is a known constant, S is the slope of the Nernst equation, and C is the blood potassium concentration.

[0089] The Nernst equation is corrected by replacing the slope with the actual slope obtained at the current blood temperature.

[0090] Based on the obtained potential information and the Nernst equation, the blood potassium concentration can be calculated and displayed on the screen.

[0091] The method for establishing the temperature-Nernst equation slope relationship model includes the following steps: Step 1: Obtain the response potential of different concentrations of serum potassium standard solutions at the current temperature; In this embodiment, the current temperature and the blood concentration of the potassium standard solution are determined within a certain range, which is determined according to the product's intended use scenario.

[0092] Specifically, the current temperature range is 4°C for refrigerated blood, 25°C for room temperature blood, and 39°C for blood from febrile patients. The potassium concentration range of the blood potassium standard solution is the range commonly used in clinical practice.

[0093] The reference electrode and working electrode used in the experiment are connected to the signal acquisition module, which is then connected to the MCU module via the power amplifier module and the digital-to-analog converter module.

[0094] At the current set temperature, the standard solutions of each blood potassium concentration were experimentally measured sequentially using the reference electrode and the working electrode to obtain the response potential corresponding to each blood potassium concentration.

[0095] Step 2: Fit the concentrations of different serum potassium standard solutions and their corresponding response potentials using the least squares method to obtain the slope of the Nernst equation at the current temperature; Specifically, at the current set temperature, a discrete point plot is obtained by using the logarithm of the concentration of each blood potassium standard solution as the abscissa and the response potential as the ordinate. The least squares method is used to perform linear fitting on the discrete points to obtain the Nernst equation at the current set temperature, and then the slope of the Nernst equation at the current set temperature can be obtained.

[0096] Step 3: Repeat steps 1-2 to obtain the slope of the Nernst equation corresponding to blood potassium standard solutions at different temperatures; In this embodiment, within a defined temperature range, steps 1-2 are repeated with a resolution increment of 0.5°C to obtain the slope of the Nernst equation corresponding to the blood potassium standard solution at different temperatures.

[0097] Step 4: Fit the blood potassium standard solutions at different temperatures and their corresponding slopes from Step 3 to obtain the temperature-Nernst equation slope relationship model.

[0098] By plotting temperature on the x-axis and the slope of the Nernst equation at different temperatures on the y-axis, a discrete point plot is created. The least squares method is then used for fitting to obtain the temperature-Nernst equation slope relationship model.

[0099] Using the method of this embodiment, the thermistor can directly collect the temperature value of the blood, instead of collecting the ambient temperature and assuming that the ambient temperature and blood temperature are instantly balanced. This ensures that the temperature collected during detection matches the actual reaction temperature, thus ensuring the accuracy of the detection results.

[0100] After the test is completed, remove the test strip. The test strip in this embodiment is a disposable item. After the test strip is removed, it can be centrally processed, which will not be described in detail here.

[0101] The blood potassium testing device of this embodiment eliminates complex steps such as centrifugation, making it convenient for families to test blood potassium levels in real time.

[0102] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A blood potassium test strip, characterized in that, The device comprises a substrate, an intermediate layer, a blood cell filtration layer, and a hydrophobic layer stacked sequentially. It also includes a working electrode, a reference electrode, and a thermistor. The working electrode, reference electrode, and thermistor are mounted on the substrate via a first groove in the substrate, and a first flexible pad is provided between the working electrode, reference electrode, and thermistor and the bottom surface of the first groove. A second flexible pad is provided between the working electrode, reference electrode, and thermistor and the intermediate layer, exposing the detection portion of the working electrode, reference electrode, and thermistor. A cavity is formed on the bottom surface of the intermediate layer above the detection portion of the working electrode, reference electrode, and thermistor. Blood channels are formed in the intermediate layer and the hydrophobic layer, communicating with the cavity. The blood channels pass through the blood cell filtration layer to filter blood cells.

2. The blood potassium test strip as described in claim 1, characterized in that, The bottom surface of the intermediate layer has a second groove, and the second flexible pad is located inside the second groove.

3. The blood potassium test strip as described in claim 1, characterized in that, The hydrophobic layer is provided with a plurality of first capillary channels, one end of which extends to the side of the hydrophobic layer and the other end is connected to a first blood groove provided on the bottom surface of the hydrophobic layer. The top surface of the intermediate layer is provided with a second blood groove corresponding to the first blood groove. The second blood groove is connected to one end of a plurality of second capillary channels, and the other end of the second capillary channels is connected to the cavity. The first capillary channel, the first blood groove, the second blood groove, and the third capillary channel constitute the blood flow channel. A blood cell filtration layer is provided between the first blood groove and the second blood groove.

4. The blood potassium test strip as described in claim 1, characterized in that, Both the hydrophobic layer and the intermediate layer are made of hydrophobic plastic film.

5. The blood potassium test strip as described in claim 1, characterized in that, The blood cell filtration layer is made of a polymer fiber membrane, which allows plasma to pass through but prevents blood cells from passing through.

6. The blood potassium test strip as described in claim 1, characterized in that, Both the first flexible pad and the second flexible pad are made of Teflon film.

7. A method for preparing a blood potassium test strip according to any one of claims 1-6, characterized in that, Includes the following steps: After preparing a first flexible pad on the bottom surface of the first groove of the substrate, a working electrode, a reference electrode and a thermistor are prepared inside the first groove. A sensitive film is fabricated on the surface of the detection portion of the working electrode; The intermediate layer and the blood cell filtration layer are bonded and fixed, and a second flexible pad is prepared in the region of the intermediate layer corresponding to the working electrode, the reference electrode and the thermistor to form an intermediate layer-blood cell filtration layer composite membrane. The intermediate layer-blood cell filtration layer composite membrane is stacked on the upper surface of the substrate, and the hydrophobic layer is stacked on the upper surface of the intermediate layer-blood cell filtration layer composite membrane. The hydrophobic layer, the intermediate layer-blood cell filtration layer composite membrane and the substrate are fixed by hot pressing.

8. A blood potassium detection device, characterized in that, The invention includes a potassium analyzer and a potassium test strip as described in any one of claims 1-6. The potassium analyzer includes a housing with a socket that matches the potassium test strip. The socket has an interface corresponding to the working electrode, the reference electrode, and the thermistor. The interface is connected to a data acquisition module installed inside the housing. The data acquisition module is connected to a data processing module.

9. A method for detecting blood potassium, characterized in that, The potassium testing device according to claim 8 is used, comprising the following steps: The potential information and current blood temperature information are obtained after the blood to be tested passes through the blood cell filter layer, falls through the cavity to the working electrode, reference electrode and the thermistor detection part. The actual slope of the Nernst equation at the current blood temperature is obtained by combining the current blood temperature information with a pre-established temperature-Nernst equation slope relationship model. The Nernst equations were corrected using the actual slopes obtained. The blood potassium concentration is obtained based on the acquired potential information and the modified Nernst equation.

10. The method for detecting blood potassium as described in claim 9, characterized in that, The method for establishing the temperature-Nernst equation slope relationship model includes the following steps: Step 1: Obtain the response potential of different concentrations of serum potassium standard solutions at the current temperature; Step 2: Fit the concentrations of different serum potassium standard solutions and their corresponding response potentials using the least squares method to obtain the slope of the Nernst equation at the current temperature; Step 3: Repeat steps 1-2 to obtain the slope of the Nernst equation corresponding to blood potassium standard solutions at different temperatures; Step 4: Fit the blood potassium standard solutions at different temperatures and their corresponding slopes from Step 3 to obtain the temperature-Nernst equation slope relationship model.

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