A method and monitoring system for quantifying body fluid secretion volume by ion concentration

Abstract

The present invention discloses a method and monitoring system for quantitatively measuring the volume of body fluid secretion by ion concentration, which relates to the field of body fluid detection technology, including: covering a hydrogel on a skin area to be detected, wherein the hydrogel can store secreted body fluid; the detection circuit samples through a sensing electrode and measures the open circuit voltage in the hydrogel; based on the Nernst equation, the ion concentration in the body fluid secretion process is calculated according to the open circuit voltage; within a preset time period, the ion concentration is measured; a simplified model of body fluid secretion is established, and a quantitative relationship between the body fluid secretion volume and the ion flux and ion concentration is established; and the body fluid secretion volume is calculated. The present invention can realize non-invasive quantitative monitoring of body fluid secretion volume and promote the application of bioelectronic sensors based on body fluid detection in the field of physiological detection sensing.

Description

Technical Field

[0001] The present invention relates to the technical field of body fluid detection, and more particularly to a method and a monitoring system for quantifying body fluid secretion volume by ion concentration. Background Art

[0002] Body fluids are composed of water in the human body and inorganic salts and organic matter dissolved in the water. They contain extremely rich physiological information. Body fluid testing is a key medical technology that aims to assess an individual's health status and disease risk by analyzing physiological fluids in the human body, such as interstitial fluid, urine, saliva, etc. Body fluids contain a wealth of information, including metabolites, proteins, DNA, etc., which can reflect the physiological state of the human body and changes in diseases.

[0003] Compared with other detection methods, body fluid testing has unique advantages. First, it is relatively simple to collect body fluid samples, without the need for invasive surgery, so it is easier to be accepted and applied. Secondly, the information carried in body fluids is diverse, which can comprehensively evaluate the overall health status of individuals, with high comprehensiveness and accuracy. In addition, with the development of modern biotechnology, body fluid detection technology continues to innovate, providing strong support for early detection of diseases, individualized treatment plans, and health management. At present, body fluid detection technology includes traditional body fluid physiological detection methods and modern biological detection technology. Traditional methods mainly include chemical analysis of blood, urine, saliva, etc., and cytological detection in specific body fluids. Modern biotechnology covers the fields of genomics, proteomics, metabolomics, and microbiomics. Through advanced methods such as high-throughput sequencing and mass spectrometry, the information in body fluids is deeply mined to provide more accurate guidance for disease diagnosis and treatment.

[0004] The implementation process of body fluid testing usually includes sample collection, pretreatment, analysis and result interpretation. Sample collection can be completed by simple blood, urine or sweat collection, followed by pretreatment to remove interfering substances, and then various analytical techniques are used to quantitatively or qualitatively analyze the components in the body fluid sample. Finally, through data analysis and interpretation, an assessment and diagnosis of the individual's health status is obtained.

[0005] At present, portable body fluid detection devices based on sweat, saliva, and interstitial fluid provide a new solution for the next generation of physiological monitoring sensors. However, in the sample collection stage of body fluid detection, existing body fluid monitoring devices have technical barriers that make it difficult to determine the amount of body fluid secretion. In response to this problem, there have been reports that attempt to collect and quantitatively analyze body fluids using microfluidic devices, but they have difficult-to-overcome defects such as extremely small monitorable volumes and complex sample preparation.

[0006] Therefore, how to provide a simple and efficient method for quantifying the volume of body fluid secretion is an urgent problem that technicians in this field need to solve in order to reduce physiological monitoring sensor errors and seek optimal body fluid analysis conditions. Summary of the invention

[0007] In view of this, the present invention provides a method and monitoring system for quantifying the volume of body fluid secretion by ion concentration. Based on the physiological basis that body fluids contain abundant ion components, the quantification of body fluid secretion volume is achieved by ion concentration sensing. This ensures that body fluid detection technology can overcome the differences in body fluid secretion caused by seasonal changes, individual skin stratum corneum thickness, skin water content, etc., and further promote the application of body fluid sampling and analysis in the field of physiological monitoring sensing.

[0008] In order to achieve the above object, the present invention adopts the following technical solution: A method for quantifying the volume of body fluid secretion by ion concentration, comprising:

[0009] Covering the skin area to be tested with a hydrogel, wherein the hydrogel is capable of storing secreted body fluids;

[0010] The detection circuit samples through the sensing electrode and measures the open circuit voltage in the hydrogel;

[0011] Based on the Nernst equation, the ion concentration in the body fluid secretion process is calculated according to the open circuit voltage;

[0012] Complete the measurement of ion concentration within a preset time period;

[0013] Establish a simplified model of body fluid secretion and establish the quantitative relationship between body fluid secretion volume and ion flux and ion concentration;

[0014] The volume of body fluid secretion was calculated.

[0015] Preferably, the method further comprises: before the detection, initializing the microprocessor through the host computer control terminal, and the microprocessor applies the electrical parameters to the detection circuit by decoding the instruction string sent by the host computer.

[0016] Preferably, the ion concentration is sodium ion concentration.

[0017] Preferably, the sensing electrode comprises a carbon-based working electrode covered with a sodium ion selective membrane and a reference electrode made by silver / silver chloride inkjet printing;

[0018] Ions in body fluids form a double electrical layer on the surface of the sensing electrode covered with a sodium ion selective membrane.

[0019] Preferably, the volume of body fluid secretion is expressed as:

[0020]

[0021] Among them, t 1 Indicates the time period of measurement; C i (t 1 ) indicates t 1 Ion concentration over time; M i Represents the amount of ion i.

[0022] Preferably, the amount of ion i species is expressed as:

[0023]

[0024] Among them, v i represents the rate of body fluid secretion; Q represents the volume flow rate of body fluid, which is obtained from the density of sweat glands in different parts of the human body and their secretion rate;

[0025] J i (t) is the flux of ion i, expressed as the differential of the amount of ion i with respect to time:

[0026]

[0027] Where c(z) represents the ion concentration and R is the radius of the body fluid secretion channel.

[0028] Preferably, when the human body is in a steady state, the ions in the body fluid are evenly distributed in the body fluid. The simplified body fluid secretion model sets the channel of body fluid secretion as a rigid body with a constant cross section, and the volume is expressed as:

[0029] dV=πR 2 dz;

[0030] Where, dz represents the channel height;

[0031] The amount of ion i per unit volume is expressed as:

[0032] dM=c i (z)πR 2 dz;

[0033] Divide both ends by the infinitesimal unit time dt, and we get:

[0034]

[0035] Preferably, a monitoring system for quantifying the volume of body fluid secretion by ion concentration comprises: a lower computer, an upper computer, a sensing electrode and a hydrogel;

[0036] Data transmission is performed between the lower computer and the upper computer;

[0037] The lower computer is connected to the sensing electrode;

[0038] The sensing electrode is connected to the hydrogel;

[0039] The hydrogel covers the skin area to be tested.

[0040] Preferably, the lower computer includes: a power supply module for providing electrical energy;

[0041] An open circuit potential measurement module, used to measure the open circuit voltage in the hydrogel through a sensing electrode;

[0042] Communication module, used for data transmission with the host computer;

[0043] Display module, used to display the measurement results in real time.

[0044] It can be seen from the above technical solutions that compared with the prior art, the present invention discloses a method and monitoring system for quantifying the volume of body fluid secretion by ion concentration, including: covering the skin area to be detected with a hydrogel, the hydrogel being able to store secreted body fluids; the detection circuit sampling through the sensing electrode to measure the open circuit voltage in the hydrogel; based on the Nernst equation, calculating the ion concentration in the body fluid secretion process according to the open circuit voltage; completing the measurement of the ion concentration within a preset time period; establishing a simplified model of body fluid secretion, establishing a quantitative relationship between the body fluid secretion volume and the ion flux and ion concentration; and calculating the body fluid secretion volume. The present invention has the following beneficial effects: 1. Realizing non-invasive body fluid collection and monitoring: The present invention realizes non-invasive quantitative body fluid secretion volume by means of ion concentration sensing, greatly reducing the patient's discomfort and a series of complications.

[0045] 2. Realize rapid body fluid detection: The measurement method based on ion concentration can obtain results quickly, which is of great significance for situations that require real-time monitoring of body fluid status (such as water and electrolyte management during exercise for athletes).

[0046] 3. Simplified body fluid detection process: The present invention estimates the secretion volume of body fluid by detecting the ion concentration in the body fluid without performing complex volume measurement, thereby simplifying the body fluid detection process, reducing the difficulty of operation, and making it easier to implement in clinical or field environments.

[0047] 4. Reducing the cost-effectiveness of body fluid testing technology: Developing a method to measure the volume of body fluid secretion based on ion concentration would reduce the need for expensive equipment, making this method more cost-effective and thus applicable in a wider range of regions and situations.

[0048] 5. Realize continuous monitoring of body fluids: The present invention helps to continuously monitor the body fluid secretion of an individual over a long period of time, especially for patients who need to manage chronic diseases, eliminating the inconvenience caused by frequent replacement of devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0050] Figure 1 A flow chart of a method for quantifying body fluid secretion volume provided in an embodiment of the present invention.

[0051] Figure 2 A schematic diagram of a simplified model of body fluid secretion provided in an embodiment of the present invention.

[0052] Figure 3 A flowchart of a host computer program control provided by an embodiment of the present invention.

[0053] Figure 4 A schematic diagram of open circuit voltage test results during movement provided by an embodiment of the present invention.

[0054] Figure 5 A schematic diagram of changes in sodium ion concentration during isokinetic secretion provided by an embodiment of the present invention.

[0055] Figure 6 A schematic diagram of the measurement results of sweat secretion volume in the collection area during exercise provided by an embodiment of the present invention.

[0056] Figure 7 A schematic diagram of the measurement results of whole body sweat secretion volume during exercise provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] The embodiment of the present invention discloses a method and monitoring system for quantitatively measuring the volume of body fluid secretion by ion concentration. Based on the physiological basis that body fluids contain abundant ion components, the volume of body fluid secretion is quantitatively measured by ion concentration sensing. This ensures that body fluid detection technology can overcome differences in body fluid secretion caused by seasonal changes, individual skin stratum corneum thickness, skin water content, etc., can achieve non-invasive quantitative monitoring of body fluid secretion volume, and promote the application of bioelectronic sensors based on body fluid detection in the field of physiological detection sensing.

[0059] Example 1

[0060] The embodiment of the present invention discloses a method for quantifying the volume of body fluid secretion by ion concentration, comprising:

[0061] Covering the skin area to be tested with a hydrogel, wherein the hydrogel is capable of storing secreted body fluids;

[0062] The detection circuit samples through the sensing electrode and measures the open circuit voltage in the hydrogel;

[0063] Based on the Nernst equation, the ion concentration in the body fluid secretion process is calculated according to the open circuit voltage;

[0064] Complete the measurement of ion concentration within a preset time period;

[0065] Establish a simplified model of body fluid secretion and establish the quantitative relationship between body fluid secretion volume and ion flux and ion concentration;

[0066] The volume of body fluid secretion was calculated.

[0067] like Figure 2 As shown, the embodiment of the present invention establishes a simplified model of body fluid secretion, establishes a quantitative relationship between body fluid secretion and ion flux and ion concentration, and improves the theoretical basis for non-invasive measurement of body fluid secretion volume.

[0068] Specifically, it also includes: before the detection, the microprocessor is initialized by the host computer control terminal, and the microprocessor applies the electrical parameters to the detection circuit by decoding the instruction string sent by the host computer.

[0069] like Figure 1 The flowchart shown shows the technical solution process of the method of the embodiment of the present invention. The embodiment of the present invention first initializes the microprocessor through the host computer mobile terminal, and the microprocessor applies the electrical parameters to the hardware detection circuit by decoding the instruction string sent by the host computer. As the body fluid secretion process proceeds, the secreted body fluid will be stored in the hydrogel covering the detection area on the skin surface, and the detection circuit obtains the volume of body fluid secretion in the process by sampling and analyzing through the sensing electrode.

[0070] Specifically, the ion concentration is sodium ion concentration.

[0071] Specifically, the sensing electrode includes a carbon-based working electrode covered with a sodium ion selective membrane and a reference electrode made by silver / silver chloride inkjet printing;

[0072] Ions in body fluids form a double electrical layer on the surface of the sensing electrode covered with a sodium ion selective membrane.

[0073] In a specific embodiment of the present invention, as shown in the attached Figure 2As shown in the figure, the simplified model of body fluid secretion uses a cylindrical container to represent the channel of body fluid secretion. When the human body is in a steady state, the ions in the body fluid are evenly distributed in the body fluid, and it is assumed that the channel of body fluid secretion is a rigid body with a uniform cross section:

[0074] dV=πR 2 dz#(1-1)

[0075] Where, dz represents the channel height;

[0076] The amount of ion i per unit volume can be expressed as:

[0077] dM=c i (z)dV#(1-2)

[0078] Substituting equation 1-1 into equation 1-2 yields:

[0079] dM=c i (z)πR 2 dz#(1-3)

[0080] Divide both ends of equation 1-3 by the infinitesimal unit time dt:

[0081]

[0082] The differential of the amount of ion i with respect to time can be expressed as the flux of ion i:

[0083]

[0084] Where c(z) represents the ion concentration and R is the radius of the body fluid secretion channel.

[0085] According to the hypothesis of isometric secretion of body fluids, v i is a constant, that is, the flux of ion i is directly proportional to the sodium ion concentration. According to the definition of the amount of substance, the amount of ion i can be expressed as:

[0086]

[0087] Among them, v i represents the secretion rate of body fluid; Q represents the volume flow rate of body fluid, v i is a constant. According to the setting of isokinetic secretion of body fluids, the flux of ion i is directly proportional to the concentration of sodium ions.

[0088] Among them, the body fluid volume flow rate Q can be obtained from the density of sweat glands in different parts of the human body and their secretion rate. Then, t can be calculated through the definition of molar concentration. 1 The volume of the solution system where the sodium ions are distributed at time 0-t 1 The volume of body fluid secreted during a period of time.

[0089] The volume of body fluid secretion is expressed as:

[0090]

[0091] Among them, t 1 Indicates the time period of measurement; C i (t 1 ) indicates t 1 Ion concentration over time; M i Represents the amount of ion i.

[0092] In the embodiment of the present invention, the specific detection method of the amount of ion substances and ion concentration is as follows: the secreted ions will form a double electric layer on the surface of the sensing electrode covered with the ion selective membrane. According to the Nernst equation, the open circuit potential of the sensing electrode is linearly related to the logarithm of the ion concentration. The ion concentration on the sensing electrode at this time can be converted by measuring the open circuit voltage at both ends of the ion selective electrode.

[0093] In the embodiment of the present invention, the body fluid may be sweat.

[0094] The embodiment of the present invention measures the quantitative volume of sweat secretion in the test area on the outer side of the forearm during 15 minutes of uniform exercise at a constant temperature (20° C.).

[0095] The open circuit voltage sensing results during the entire movement are shown in the attached figure. Figure 4 As shown. Figure 4 It can be seen that within about 4 minutes of the beginning of exercise, the open circuit voltage response basically remains at 0, and sweat has not yet begun to be secreted. 4 minutes after the start of exercise, the open circuit voltage response appears to be lower than the baseline value. At this time, it is in the early stage of sweat secretion. The sweat secreted by the sweat glands is almost entirely water and has few ion components, so a response lower than the baseline value appears. About 2 minutes after the initial secretion, the increase in body fluid ion concentration caused by the loss of body water activates the body's electrolyte balance homeostasis regulation mechanism, the ion channels in the body open, and sodium ions flow out of the body with the secretion of sweat and are stored in the hydrogel. At this time, the open circuit voltage response rises and is maintained in a dynamic equilibrium range (7-15min), which corresponds to the isokinetic secretion state of sweat.

[0096] As attached Figure 5 As shown, for the analysis of the isokinetic secretion state, the sweat gland density of the outer side of the forearm of the human body is about 150 / cm 2 The typical sweat secretion rate of human sweat glands is about 10nL / min / piece. The radius of the working electrode in the collection area of ​​the system is 2mm. Substituting the calculation formula obtained in the embodiment of the present invention into the calculation formula, the change of the sweat collected in the working electrode area with the exercise time in the process can be obtained as shown in the attached figure. Figure 6 Finally, according to physiological theory, the human body has about 3×10 6According to this calculation, the results of the whole body sweat secretion volume measurement during exercise are shown in the attached figure. Figure 7 As shown in the figure, during this intensity of exercise, the average human body secretes about 20.8 mL of sweat per minute. The measurement results are consistent with the physiological range of sweat secretion volume of adults under normal exercise conditions.

[0097] Example 2

[0098] The embodiment of the present invention discloses a monitoring system for quantitatively measuring the volume of body fluid secretion by ion concentration, comprising: a lower computer, an upper computer, a sensing electrode and a hydrogel;

[0099] Data transmission is performed between the lower computer and the upper computer;

[0100] The lower computer is connected to the sensing electrode;

[0101] The sensing electrode is connected to the hydrogel;

[0102] The hydrogel covers the skin area to be tested.

[0103] Specifically, the lower computer includes: a power supply module for providing electric energy;

[0104] An open circuit potential measurement module, used to measure the open circuit voltage in the hydrogel through a sensing electrode;

[0105] Communication module, used for data transmission with the host computer;

[0106] Display module, used to display the measurement results in real time.

[0107] Example 3

[0108] The embodiment of the present invention discloses a wearable non-invasive sweat monitoring system. The embodiment of the present invention can monitor the sodium ion concentration in the sweat of the user in real time during the sweating process, thereby realizing the quantitative measurement of the sweat secretion volume.

[0109] The whole system consists of three parts: the hardware lower computer, the mobile upper computer and the electrode front end. The lower computer is a wearable sweat monitoring device with data display function. The size of the whole system is 34mm*34mm. The hardware circuit of the device is mainly divided into four parts: a power supply system composed of a 3.7V, 500mAh lithium-ion battery, which can achieve continuous measurement for more than 6 hours; an open circuit potential measurement module based on a constant potential instrument chip, which can achieve accurate measurement of open circuit potential within a 1mV error range; a low-power Bluetooth communication module with an operating current as low as 270uA; and a color LCD display module that can display the measurement results in real time.

[0110] The program flow design of the host computer is as follows Figure 3As shown, the subject first initializes the system parameters through the upper computer human-computer interaction interface, and then starts the active sweating process under exercise stimulation. During the active sweating process, the sodium ion concentration of sweat in the hydrogel attached to the sweat collection area is measured every 1 minute. After completing the sweat collection cycle, the lower computer calculates the subject's sweat secretion volume within the exercise time range based on the measured sodium ion concentration and exercise time, and synchronously displays the measurement results on the LCD display module and the display interface of the Android APP.

[0111] The electrode front end in the embodiment of the present invention is a two-electrode measurement system made of polyethylene terephthalate (PET) as a substrate. Among them, the sodium ion sensing electrode is composed of a carbon-based working electrode covered with a sodium ion selective membrane and a reference electrode made by silver / silver chloride inkjet printing. Structurally, the total size of the electrode is 12mm*34mm, and the working electrode area is a circular area with a radius of 2mm. Before actual measurement, the electrode sensing front end must be covered with a layer of hydrogel with good water storage performance to preserve the secreted sweat.

[0112] Using this device, an experiment was conducted in an embodiment of the present invention: in a 20°C space, the subject wore the sweat detection system and exercised for 20 minutes, and the open circuit voltage response of the sodium ions in the hydrogel was measured every 1 minute during the exercise. According to the Nernst equation, the size of the sodium ion concentration during exercise is obtained through the linear relationship between the open circuit voltage and the logarithm of the sodium ion concentration. After the entire sweat cycle is measured, the integral of the sodium ion concentration over time during the isokinetic secretion of sweat is multiplied by the sweat flow rate in the area, and the volume of sweat secretion during exercise can be quantified using ion concentration sensing.

[0113] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0114] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for quantifying the volume of body fluid secretion by ion concentration, characterized in that: include: Covering the skin area to be tested with a hydrogel, wherein the hydrogel is capable of storing secreted body fluids; The detection circuit samples through the sensing electrode and measures the open circuit voltage in the hydrogel; Based on the Nernst equation, the ion concentration in the body fluid secretion process is calculated according to the open circuit voltage; Complete the measurement of ion concentration within a preset time period; Establish a simplified model of body fluid secretion and establish the quantitative relationship between body fluid secretion volume and ion flux and ion concentration; The volume of body fluid secretion was calculated; The volume of body fluid secretion is expressed as: Where t1 represents the measurement time period; C i (t1) represents the ion concentration during time t1; M i Indicates the amount of ion i. The amount of ion i is expressed as: Among them, v i represents the rate of body fluid secretion; Q represents the volume flow rate of body fluid, which is obtained from the density of sweat glands in different parts of the human body and their secretion rate; J i (t) is the flux of ion i, expressed as the differential of the amount of ion i with respect to time: Where c(z) represents the ion concentration and R is the radius of the body fluid secretion channel. When the human body is in a steady state, the ions in the body fluid are evenly distributed in the body fluid. The simplified model of body fluid secretion sets the channel of body fluid secretion as a rigid body with equal cross-section, and the volume is expressed as: dV=πR 2 dz; Where, dz represents the channel height; The amount of ion i per unit volume is expressed as: dM=c i (of)πR 2 d; Divide both ends by the infinitesimal unit time dt, and we get:

2. A method for quantifying body fluid secretion volume by ion concentration according to claim 1, characterized in that: Also includes: Before the detection, the microprocessor is initialized through the host computer control terminal, and the microprocessor applies the electrical parameters to the detection circuit by decoding the instruction string sent by the host computer.

3. The method for quantifying the volume of body fluid secretion by ion concentration according to claim 1, characterized in that: The ion concentration is the sodium ion concentration.

4. The method for quantifying the volume of body fluid secretion by ion concentration according to claim 1, characterized in that: The sensing electrode comprises a carbon-based working electrode covered with a sodium ion selective membrane and a reference electrode made by silver / silver chloride inkjet printing; Ions in body fluids form a double electrical layer on the surface of the sensing electrode covered with a sodium ion selective membrane.

5. A monitoring system for quantifying the volume of body fluid secretion by ion concentration, using the method for quantifying the volume of body fluid secretion by ion concentration as claimed in any one of claims 1 to 4, characterized in that: include: Lower computer, upper computer, sensing electrodes and hydrogel; Data transmission is performed between the lower computer and the upper computer; The lower computer is connected to the sensing electrode; The sensing electrode is connected to the hydrogel; The hydrogel covers the skin area to be tested.

6. A monitoring system for quantifying body fluid secretion volume by ion concentration according to claim 5, characterized in that: The lower computer includes: a power supply module for providing electric energy; An open circuit potential measurement module, used to measure the open circuit voltage in the hydrogel through a sensing electrode; Communication module, used for data transmission with the host computer; Display module, used to display the measurement results in real time.

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