Anti-interference materials, anti-interference films, their preparation methods and applications

Abstract

This application relates to the field of biosensing technology, and particularly to anti-interference materials, anti-interference membranes, their preparation methods, and applications. Anti-interference materials include carboxylated materials, specifically at least one of carboxylated materials containing conjugated π bonds and carboxylated molecular sieves. These materials isolate interfering components through electrostatic repulsion and adsorption, preventing anionic and neutral molecular interference components in body fluids from affecting detection results. Anti-interference membranes, including these materials, have simplified preparation processes and can be used in electrochemical sensors and colorimetric test strips. They eliminate the need for interfering substance processing, save detection time, and improve detection accuracy. Their anti-interference effect is more than 30 times that of existing membranes.

Description

Technical Field

[0001] This application belongs to the field of biosensing technology, and in particular relates to anti-interference materials, anti-interference membranes, their preparation methods and applications. Background Technology

[0002] In biosensing technology, besides the target substance, many interfering components can affect the detection results. These interfering components generally need to be pre-treated or anti-interference measures should be taken during detection. For example, when detecting substances such as glucose (a marker for diabetes), creatine (a marker for prostate cancer), and hydrogen peroxide (generated by the reaction of the analyte with an enzyme), other electroactive interfering components will generate interfering signals upon contact with the electrode. Examples include uric acid (UA, anionic), ascorbic acid (AA, anionic), and acetaminophen (AC, an antipyretic, neutral molecule). These electroactive substances are the most prevalent electroactive interfering components in human body fluids (blood, urine, tissue fluid, etc.), and are primarily anionic and neutral molecules. In existing technologies, besides pre-treatment, coatings are generally used to hinder the mass transfer of electroactive interfering components and reduce interference signals. The most commercially effective anti-interference membrane is the Nafion membrane from DuPont, which can exclude anionic interfering components through the electrical repulsion of the membrane layer, but it cannot block neutral molecules. Furthermore, it can only exclude about 95% of anionic interfering molecules, making its anti-interference performance far from sufficient when the target substance content is very low (e.g., 1% of the interfering component). In addition, some studies have reduced the pore size of membrane materials to a few tenths of a nanometer, thereby utilizing volume repulsion to create a interception effect on some electrically active interfering components.

[0003] Therefore, materials or anti-interference films with better anti-interference effects are needed to reduce the impact of electroactive interfering components on the detection results and make the detection results more accurate. Summary of the Invention

[0004] The purpose of this application is to provide anti-interference materials, anti-interference membranes, their preparation methods and applications, in order to solve the problem that electroactive interfering components can affect detection results in existing biosensing technologies.

[0005] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows:

[0006] In a first aspect, this application provides an anti-interference material. The anti-interference material includes a carboxylated material, which includes at least one of a carboxylated material containing conjugated π bonds and a carboxylated molecular sieve.

[0007] The anti-interference material of this application includes these carboxylated materials, which can achieve the isolation effect of interfering components through electrostatic repulsion and adsorption, thereby avoiding the influence of anionic and neutral molecular interfering components in body fluids on the detection results and improving the accuracy of the detection results.

[0008] In some embodiments, the conjugated π-bonded carboxylated material includes at least one of carboxylated graphene, carboxylated carbon nanotubes, and carboxylated metal-organic framework materials.

[0009] In some embodiments, the carboxyl functional groups contained in the carboxylated material account for 0.001% to 30% of the mass of the carboxylated material.

[0010] In some embodiments, the pore size of the carboxylated molecular sieve is 0.3 nm to 50 nm.

[0011] In some embodiments, the anti-interference material also includes a material containing conjugated π bonds, which does not contain carboxyl groups.

[0012] In some embodiments, the conjugated π-bond material includes at least one of carbon nanotubes, graphene, C60, graphite, and metal-organic framework materials.

[0013] In some embodiments, the mass ratio of carboxylated material to material containing conjugated π bonds is (1-95):(5-99).

[0014] Secondly, this application provides an anti-interference film. The materials contained in the anti-interference film include the anti-interference materials of this application.

[0015] The anti-interference membrane of this application exhibits excellent isolation effects against anionic and neutral molecular interference components without affecting the detection signal of the target substance. Using this membrane eliminates the need for pre-detection treatment of interfering components, saving time, increasing detection speed, and providing better anti-interference performance and higher accuracy than existing membrane technologies.

[0016] In some embodiments, the materials contained in the anti-interference film also include an adhesive.

[0017] In some embodiments, the adhesive includes at least one of gum arabic, perfluorosulfonic acid resin, chitosan, polyurethane, and polyethylene.

[0018] In some embodiments, the mass ratio of the anti-interference material to the adhesive is (10-99):(1-90).

[0019] Thirdly, this application provides a method for preparing an anti-interference film, comprising the following steps:

[0020] An anti-interference film is obtained by forming an anti-interference material.

[0021] Among them, the anti-interference material is the anti-interference material of this application.

[0022] The anti-interference membrane prepared by the method of this application is used to detect target substances. It has a fast detection speed and better anti-interference effect and higher accuracy than existing membranes.

[0023] In some embodiments, before the film-forming process, the anti-interference material and the binder are mixed to form a mixed slurry, and then the mixed slurry is subjected to film-forming treatment.

[0024] Fourthly, this application provides the application of anti-interference membranes in electrochemical sensors and colorimetric test strips.

[0025] The anti-interference membrane of this application can be used in electrochemical sensors or colorimetric test strips to detect glucose, sarcosine, etc. In these applications, there is no need to pre-treat interfering components before detection, thus resulting in fast detection speed and high accuracy.

[0026] Fifthly, this application provides an electrochemical sensor. The electrochemical sensor includes an anti-interference membrane, which includes the anti-interference membrane of this application or an anti-interference membrane prepared by the preparation method of this application.

[0027] The electrochemical sensor proposed in this application has a fast detection speed, good anti-interference effect, high accuracy, and wide application.

[0028] In some embodiments, an electrode and an enzyme membrane are further included, with an anti-interference membrane disposed between the electrode and the enzyme membrane, and the anti-interference membrane being attached to the electrode and the enzyme membrane; or

[0029] The enzyme membrane is placed between the electrode and the anti-interference membrane, and the enzyme membrane adheres to both the electrode and the anti-interference membrane.

[0030] In some embodiments, the electrode material includes any one of noble metals, glassy carbon, and graphite, and

[0031] The enzyme membrane contains any one of glucose oxidase, sarcosine oxidase, cholesterol oxidase, or pyruvate oxidase; or

[0032] An anti-interference membrane is placed between the electrode and the enzyme membrane, and the anti-interference membrane is attached to the electrode and the enzyme membrane. The enzyme membrane contains urate oxidase or ascorbate oxidase. Attached Figure Description

[0033] 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.

[0034] Figure 1 This is a SEM image of an anti-interference film according to an embodiment of this application;

[0035] Figure 2 This is a time-current graph of H2O2 detection by an electrochemical sensor according to an embodiment of this application, showing interference immunity.

[0036] Figure 3 This is a time-current graph showing the sensitivity of an electrochemical sensor for detecting sarcosine according to an embodiment of this application;

[0037] Figure 4 This is a concentration-current graph showing the sensitivity of an electrochemical sensor for detecting sarcosine according to an embodiment of this application;

[0038] Figure 5 This is a concentration-current graph of sarcosine anti-interference detection by an electrochemical sensor according to an embodiment of this application. Detailed Implementation

[0039] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0040] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0041] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0042] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0043] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0044] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass in the embodiments of this application can be a well-known unit of mass in the chemical industry, such as μg, mg, g, or kg.

[0045] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0046] The first aspect of this application provides an anti-interference material. The anti-interference material includes a carboxylated material, which may include at least one of a carboxylated material containing conjugated π bonds and a carboxylated molecular sieve.

[0047] Through research, the inventors have discovered that carboxylated materials containing conjugated π bonds or carboxylated molecular sieves can effectively isolate electroactive interfering components such as uric acid (UA), ascorbic acid (AA), and acetaminophen (AC). These carboxylated materials achieve this isolation effect through the principles of electrostatic repulsion and adsorption. Specifically: ① At the microscopic level, the carboxyl groups in these carboxylated materials can dissociate protons and carry a negative charge, which is the same as the charge of anionic interfering components such as UA and AA under physiological conditions. Therefore, these interfering components can be electrostatically repelled; ② Carboxylated materials containing conjugated π bonds form π-π chemical bonds with molecules containing benzene rings, such as acetaminophen, through conjugated π bonds, thereby interacting and adsorbing acetaminophen onto the carboxylated material, making it difficult for it to pass through and thus having a blocking effect. The repulsion principle for other neutral molecular interfering components is similar; ③ In carboxylated molecular sieves, due to the strong polarity inside the pores of the molecular sieve crystals, there is a strong physical adsorption capacity for polar and unsaturated molecules, thereby preventing the passage of neutral molecular interfering components. The anti-interference material in this application differs from existing graphene and carbon nanotube films, which require pore sizes below a few tenths of a nanometer to achieve a flow-blocking effect. This material, containing conjugated π-bond carboxyl groups, does not rely on volume repulsion for flow blocking, therefore it does not have specific requirements regarding pore size. The inventors have found that these materials, even with common pore sizes of tens of nanometers, can effectively isolate interfering components. Furthermore, the effectiveness of this anti-interference material is more than 30 times that of existing Nafion films and more than 60 times that of chitosan films.

[0048] The carboxylated materials mentioned above refer to materials containing carboxyl functional groups. These are materials generated through carboxylation reactions, such as hydrolysis and oxidation. For example, a substrate, concentrated acid, and oxidant can be mixed and the solvent removed to obtain a carboxylated material. This carboxylated material can be obtained by carboxylation using existing methods. Conjugated π bonds, also known as delocalized π bonds, large conjugated π bonds, or large π bonds, generally refer to covalent bonds formed when the p orbitals of atoms approach each other perpendicular to the internuclear connection line of the bonding atoms, resulting in electron cloud overlap. These overlapping p orbitals are not completely filled; electrons are not confined to the movement between adjacent atoms but can move within all of these p orbitals, meaning they can move within the molecule and are distributed among several atoms. Examples include carbon nanotubes and some polycyclic aromatic hydrocarbons, which contain conjugated π bonds. Carboxylated materials containing conjugated π bonds refer to carboxylated materials containing conjugated π bonds. These conjugated π bonds can be present in the substrate before carboxylation and retained after carboxylation, or they can be formed during the carboxylation process, as long as the carboxylated material contains conjugated π bonds. Carboxylated molecular sieves refer to molecular sieves with pore sizes within a certain range, containing carboxyl functional groups, such as some hydrated aluminosilicate materials containing carboxyl functional groups. When the anti-interference material includes carboxylated molecular sieves, since the adsorption properties of the molecular sieve are mainly related to the pore size, in some embodiments, the pore size of the carboxylated molecular sieve can be 0.3 nm to 50 nm. In exemplary examples, the pore size can include, but is not limited to, 0.3 nm, 1 nm, 3 nm, 5 nm, 10 nm, 20 nm, 30 nm, and 50 nm.

[0049] In some embodiments, the conjugated π-bonded carboxylated material may include at least one of carboxylated graphene, carboxylated carbon nanotubes, and carboxylated metal-organic framework materials.

[0050] Through research, the inventors have found that using carboxylated materials containing conjugated π bonds as anti-interference materials significantly isolates interfering components. Even if the concentration of interfering components is much higher than the concentration of the target substance, it will not cause interference and affect the detection results. Furthermore, even if the target substance is only a few micromoles per liter (hereinafter referred to as μM), there is still a relatively obvious electrical signal. The carboxylated graphene mentioned above can include carboxylated graphene, carboxylated graphene oxide, and carboxylated reduced graphene oxide; carboxylated carbon nanotubes can include carboxylated single-walled carbon nanotubes and carboxylated multi-walled carbon nanotubes; carboxylated metal-organic framework materials can include carboxylated zinc-based, iron-based, nickel-based, cadmium-based, zirconium-based, cobalt-based, and other metal-organic framework materials. The π-bond-containing carboxylated materials mentioned above can include any one of carboxylated graphene, carboxylated carbon nanotubes, and carboxylated metal-organic framework materials, or more than two. For example, a mass ratio of 8:2 of carboxylated graphene and carboxylated carbon nanotubes can be used as anti-interference materials.

[0051] In some embodiments, the carboxyl functional groups in the carboxylated material account for 0.001% to 30% of the mass of the carboxylated material. The inventors have found that the content of carboxyl functional groups in these carboxylated materials within these ranges can achieve a relatively reliable anti-interference effect, meeting the requirements of commercial applications. In exemplary examples, the mass ratio of carboxyl functional groups to the carboxylated material may include, but is not limited to, 0.001%, 0.01%, 0.1%, 1%, 5%, 10%, 20%, and 30%.

[0052] In some embodiments, the anti-interference material also includes a material containing conjugated π bonds, which does not contain carboxyl functional groups.

[0053] Through research, the inventors have discovered that, in addition to the carboxylated materials mentioned above as anti-interference materials, other materials containing conjugated π bonds can also be included to further enhance the isolation effect on neutral molecular interference components. In the example, these carboxyl-free materials containing conjugated π bonds can include, but are not limited to, at least one of carbon nanotubes (including single-walled carbon nanotubes and multi-walled carbon nanotubes), graphene (including graphene, graphene oxide, and reduced graphene oxide), C60, graphite, and metal-organic framework materials. The mass ratio of the carboxylated materials mentioned above to these materials containing conjugated π bonds can be (1–95):(5–99) to balance the isolation effect of the anti-interference material on anionic and neutral molecular interference components, enabling the entire anti-interference material to achieve the desired effect of isolating interference components and accurately measuring the target substance. In the example, the mass ratio of the carboxylated material to the conjugated π-bonded material may include, but is not limited to, (1:99), (5:95), (10:90), (30:70), (50:50), (65:35), (80:20), and (95:5).

[0054] A second aspect of this application provides an anti-interference film. The anti-interference film comprises materials including the anti-interference materials described in the preceding embodiments.

[0055] The anti-interference membrane of this application contains the anti-interference materials described in the preceding embodiments, thus exhibiting excellent isolation effects against anionic and neutral molecular interference components without affecting the detection signal of the target substance. The thickness of the anti-interference membrane is not specifically required; common thicknesses ranging from a few micrometers to a few millimeters can be designed according to actual application. Using this membrane eliminates the need for pre-detection treatment of interfering components, saving time, increasing detection speed, and providing better anti-interference performance and higher accuracy than existing membranes. The inventors have found that the anti-interference effect of the membrane made from these materials is more than 30 times that of existing Nafion membranes and more than 60 times that of chitosan membranes.

[0056] In some embodiments, the materials contained in the anti-interference film may also include an adhesive.

[0057] Through research, the inventors have found that, in order to improve the film-forming quality, strength, toughness, and other properties of the anti-interference film, the film may also include an adhesive. In exemplary cases, the adhesive includes, but is not limited to, at least one of gum arabic, perfluorosulfonic acid resin, chitosan, polyurethane, and polyethylene. To ensure the anti-interference effect of the anti-interference film while also considering the physical properties of the film, the mass ratio of the anti-interference material to the adhesive can be (10–99):(1–90). In exemplary cases, the mass ratio of the anti-interference material to the adhesive can include, but is not limited to, 10:90, 30:70, 50:50, 70:30, 80:20, and 99:1.

[0058] A third aspect of this application provides a method for preparing an anti-interference film. The preparation method may include the following steps:

[0059] S01: The anti-interference materials, including those in the embodiments described above, are subjected to film-forming treatment to obtain an anti-interference film.

[0060] The anti-interference material here can be the anti-interference material of the above-described embodiments. Therefore, the anti-interference material contains at least one of conjugated π-bond carboxylated materials and carboxylated molecular sieves. It can also further include the conjugated π-bond material (without carboxyl groups) contained in the anti-interference material of the above-described embodiments. The film formation method needs to be adapted accordingly. For example, when two carboxylated materials are included, a mixed solution can be prepared by stirring, ultrasonic mixing, etc. Since carboxylated materials generally have good water dispersibility, the mixed solution can be drop-coated, sprayed, or spin-coated onto the substrate surface, and then dried or heated to form a film, which is the desired anti-interference film. Another example: when the above-described conjugated π-bond material is also included, the anti-interference material is graphene and carboxylated carbon nanotubes, or carbon nanotubes and carboxylated graphene. Since graphene and carbon nanotubes generally have poor water dispersibility and are prone to precipitation, volatile organic solvents, dispersants, etc., can be added appropriately to improve the dispersion effect of the mixed solution. The mixed solution is then coated onto the substrate surface and dried to form a film. For example, carbon nanotubes, graphene, and molecular sieves can be mixed, and then subjected to a carboxylation reaction with concentrated acid and an oxidant. The resulting mixture can then be used to prepare a membrane. The membrane material can be fully carboxylated, or the amounts of concentrated acid and oxidant can be controlled so that the membrane material is not fully carboxylated, including both carboxylated materials and materials containing conjugated π bonds as mentioned above. The anti-interference membrane prepared by the method described in this application is used to detect target substances. It has a fast detection speed and better anti-interference effect and higher accuracy than existing membranes.

[0061] In some embodiments, before film formation, the anti-interference material and binder can be mixed to form a slurry, and then the slurry is subjected to film formation. Adding a binder further improves the film-forming effect of the slurry, enhancing the strength and toughness of the anti-interference film. The mass ratio of the anti-interference material to the binder can be referenced above as (10–99):(1–90).

[0062] The fourth aspect of this application provides the application of the anti-interference films described in the above embodiments in electrochemical sensors and colorimetric test strips.

[0063] This application describes an anti-interference membrane used in electrochemical sensors or colorimetric test strips for the detection of glucose, sarcosine, and other substances. In application, the anti-interference membrane can be placed between the original sensor / test strip and the sample to isolate interfering components. For example, a glucose colorimetric test strip includes, from bottom to top, a bonded hydrogen peroxide colorimetric agent membrane, a glucose oxidase membrane, and an anti-interference membrane. Placing the sample on the anti-interference membrane allows for glucose detection without interference. Alternatively, the anti-interference membrane can be placed inside the electrochemical sensor or test strip, between the active material and the responder. For example, a uric acid colorimetric test strip includes, from bottom to top, a bonded hydrogen peroxide colorimetric agent membrane, an anti-interference membrane, and a uric acid oxidase membrane. Placing the sample on the uric acid oxidase membrane allows uric acid detection because the generated hydrogen peroxide can pass through the anti-interference membrane. After applying the anti-interference membrane, pre-treatment of interfering components is unnecessary, resulting in faster detection speeds and higher accuracy.

[0064] This application provides an electrochemical sensor in a fifth aspect. The electrochemical sensor includes an anti-interference membrane, which may include the anti-interference membranes described in the preceding embodiments or the anti-interference membranes prepared by the methods described in the preceding embodiments. Because the embodiments of this application include the anti-interference membranes described in the preceding embodiments, the electrochemical sensor has a fast detection speed, good anti-interference effect, high accuracy, and wide application.

[0065] In some embodiments, the device may further include an electrode and an enzyme membrane, with an anti-interference membrane disposed between the electrode and the enzyme membrane, and the anti-interference membrane being attached to the electrode and the enzyme membrane; or

[0066] The enzyme membrane is placed between the electrode and the anti-interference membrane, and the enzyme membrane adheres to both the electrode and the anti-interference membrane.

[0067] The inventors have researched and developed an electrochemical sensor that includes an anti-interference membrane, which can have two structures. ① One type involves the anti-interference membrane being positioned between the electrode and the enzyme membrane. This structure is universal and can detect target substances such as glucose, sarcosine, hydrogen peroxide, cholesterol, and pyruvate while isolating interfering components. The enzyme membrane simply needs to contain oxidases such as glucose oxidase and sarcosine oxidase. It can also detect interfering components such as uric acid and ascorbic acid. The enzyme membrane simply needs to contain oxidases such as urate oxidase and ascorbic acid oxidase. When the sample is coated onto the enzyme membrane surface, the hydrogen peroxide generated by the enzyme membrane and these substances can pass through the anti-interference membrane. Therefore, both target substances and interfering components can be detected, and the interfering components will not come into contact with the electrode and affect the detection results. ② The other structure involves the enzyme membrane being positioned between the electrode and the anti-interference membrane. This is limited to detecting target substances such as glucose, sarcosine, cholesterol, pyruvate, and hydrogen peroxide. The target substances can pass through the anti-interference membrane, and a corresponding enzyme membrane is placed for detection. The anti-interference membrane isolates interfering components.

[0068] In some embodiments, the electrode material can include any one of noble metals, glassy carbon, and graphite. Noble metals can include gold, silver, platinum, palladium, iridium, etc., and can also be noble metal alloys. The electrode structure can be sheet-like, mesh-like, rod-like, etc. Hydrogen peroxide, after the enzyme membrane reacts with the target substance or interfering component, can rapidly generate a current signal on the electrode, thereby achieving the detection effect of electrochemical sensing. Therefore, the electrochemical sensor in this application embodiment saves detection time, has a fast detection speed, good anti-interference effect, high accuracy, and wide application. It should be noted that electrochemical sensors are not limited to common electronic device forms. As long as they rely on the electrochemical sensing principle, they belong to electrochemical sensors. They can be in other structural forms such as electrochemical sensor test strips. For example, attaching an anti-interference film to the surface of a sheet or mesh electrode, and then attaching a layer of uric acid oxidase membrane, forming a test strip, also belongs to uric acid electrochemical sensors.

[0069] The following description is based on specific embodiments.

[0070] 1. Case Studies of Anti-interference Materials

[0071] Example A1

[0072] This embodiment provides an anti-interference material, including carboxylated graphene.

[0073] This carboxylated graphene was prepared according to the following method:

[0074] The graphene is pretreated with ultrasound for 30 min to 1 h, then acidified with a mixture of concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 3:1 for 3 hours, and then the solvent is removed to obtain the product.

[0075] Example A2

[0076] This embodiment provides an anti-interference material, including carboxylated carbon nanotubes.

[0077] Example A3

[0078] This embodiment provides an anti-interference material, comprising a carboxylated graphene:carboxylated carbon nanotube in a mass ratio of 8:2.

[0079] Example A4

[0080] This embodiment provides an anti-interference material, including a carboxylated zinc-based organic framework material, wherein the organic ligand is ethylenediamine.

[0081] Example A5

[0082] This embodiment provides an anti-interference material, including a carboxylated molecular sieve, the original molecular sieve model being 13X.

[0083] Example A6

[0084] This embodiment provides an anti-interference material comprising a carboxylated graphene:carbon nanotube in a mass ratio of 9:1.

[0085] 2. Case Study on Anti-interference Films and Their Preparation Methods

[0086] Example B1

[0087] This embodiment provides an anti-interference film with a thickness of 20 μm. The materials contained include the anti-interference material of Example A1 and gum arabic (adhesive), and the mass ratio of the anti-interference material to the adhesive is 9:1.

[0088] The preparation method of the anti-interference film includes the following steps:

[0089] S1. Mix and disperse the anti-interference material and the binder in water at a mass ratio of 9:1 to obtain a mixed solution;

[0090] S2. Coat the mixed solution onto a glass substrate, let it dry at room temperature to form a film, and peel it off to obtain the anti-interference film.

[0091] Example B2

[0092] This embodiment provides an anti-interference film and a method for preparing the anti-interference film. The only difference from Embodiment B1 is that the anti-interference material is adjusted to the anti-interference material of Embodiment A2.

[0093] Example B3

[0094] This embodiment provides an anti-interference film and a method for preparing the anti-interference film. The only difference from Embodiment B1 is that the anti-interference material is adjusted to the anti-interference material of Embodiment A3.

[0095] Example B4

[0096] This embodiment provides an anti-interference film and a method for preparing the anti-interference film. The only difference from Embodiment B1 is that the anti-interference material is adjusted to the anti-interference material of Embodiment A4.

[0097] Example B5

[0098] This embodiment provides an anti-interference film and a method for preparing the anti-interference film. The only difference from Embodiment B1 is that the anti-interference material is adjusted to the anti-interference material of Embodiment A5.

[0099] Example B6

[0100] This embodiment provides an anti-interference film and a method for preparing the anti-interference film. The only difference from Embodiment B1 is that the anti-interference material is adjusted to the anti-interference material of Embodiment A6.

[0101] Comparative Example B1

[0102] This comparative example provides an anti-interference film and a method for preparing the anti-interference film. The only difference from Example B1 is that the anti-interference material is changed to chitosan.

[0103] Comparative Example B2

[0104] This comparative example provides an anti-interference film and a method for preparing the anti-interference film. The only difference from Example B1 is that the anti-interference material is changed to the material contained in commercial Nafion films (perfluorosulfonic acid resin and polytetrafluoroethylene).

[0105] The preparation method of the anti-interference film includes the following steps:

[0106] S1. Mix the Nafion membrane and the binder at a mass ratio of 9:1, and then mix and disperse them with acetic acid solution to obtain a mixed solution;

[0107] S2. Coat the mixed solution onto a glass substrate, let it dry at room temperature to form a film, and peel it off to obtain the anti-interference film.

[0108] The acetic acid solution here is mainly used to dissolve the original commercial Nafion membrane.

[0109] 3. Case Studies of Electrochemical Sensors

[0110] Example C1

[0111] This embodiment provides an electrochemical sensor, including a screen-printed platinum electrode, an anti-interference membrane as described in Example B1, and an enzyme membrane. The anti-interference membrane is disposed between the electrode and the enzyme membrane and is attached to both.

[0112] Example C2

[0113] This embodiment provides an electrochemical sensor, which differs from Embodiment C1 in that the anti-interference membrane is the same as that in Embodiment B2.

[0114] Example C3

[0115] This embodiment provides an electrochemical sensor, which differs from Embodiment C1 in that the anti-interference membrane is the same as that in Embodiment B3.

[0116] Example C4

[0117] This embodiment provides an electrochemical sensor, which differs from Embodiment C1 in that the anti-interference membrane is the same as that in Embodiment B4.

[0118] Example C5

[0119] This embodiment provides an electrochemical sensor, which differs from Embodiment C1 in that the anti-interference membrane is the same as that in Embodiment B5.

[0120] Example C6

[0121] This embodiment provides an electrochemical sensor, which differs from Embodiment C1 in that the anti-interference membrane is the same as that in Embodiment B6.

[0122] Example C7

[0123] This embodiment provides an electrochemical sensor, which differs from Embodiment C1 in that the anti-interference membrane is the same as that in Embodiment B7.

[0124] Example C8

[0125] This embodiment provides an electrochemical sensor, which differs from Embodiment C3 only in that the enzyme membrane is disposed between the electrode and the anti-interference membrane.

[0126] Comparative Example C1

[0127] This comparative example provides an electrochemical sensor, which differs from Example C1 in that the anti-interference film is the same as that of Comparative Example B1.

[0128] Comparative Example C2

[0129] This comparative example provides an electrochemical sensor, which differs from Example C1 in that the anti-interference film is the same as that of Comparative Example B2.

[0130] Comparative Example C3

[0131] This comparative example provides an electrochemical sensor, which differs from Example C1 in that it does not include an anti-interference membrane.

[0132] In the examples C1 to C7 and comparative examples C1 to C3, the enzyme membranes may contain any one of glucose oxidase, sarcosine oxidase, cholesterol oxidase, pyruvate oxidase, urate oxidase, and ascorbic acid oxidase. The corresponding electrochemical sensor is obtained by selecting whichever enzyme is used.

[0133] The enzyme membrane in Example C8 may contain any one of glucose oxidase, sarcosine oxidase, cholesterol oxidase, or pyruvate oxidase. The choice of enzyme determines the corresponding electrochemical sensor.

[0134] 4. Characterization of anti-interference materials and anti-interference films

[0135] The anti-interference materials of Examples A1 to A6 and the anti-interference films of Examples B1 to B6 were photographed using an electron microscope. The SEM image of the anti-interference film of Example B3 is shown below. Figure 1 .

[0136] 5. Detection results of anti-interference membrane and electrochemical sensor

[0137] 5.1 Qualitative Measurement

[0138] The enzyme membranes in Examples C1 to C7 and Comparative Examples C1 to C3 all contained only glucose oxidase. When glucose-containing body fluid was dropped onto the glucose oxidase of the electrochemical sensor, the sensor readings in Examples C1 to C7 and Comparative Examples C1 to C3 all changed, indicating that glucose could be detected in all of them.

[0139] When glucose-free bodily fluid was dropped onto the glucose oxidase of the electrochemical sensor, it was found that the sensor readings of Examples C1 to C7 did not change, while the sensor readings of Comparative Examples C1 to C3 all changed. This indicates that Comparative Examples C1 to C3 were interfered with, while the anti-interference membrane of this application can isolate interfering components in the bodily fluid and has high detection accuracy.

[0140] 5.2 Quantitative Measurement

[0141] Electrochemical sensors, including Examples C3 and Comparative Examples C1 to C3, are provided to detect 10 μM hydrogen peroxide (H2O2), 10 μM uric acid (UA), 10 μM ascorbic acid (AA), and acetaminophen (AC) sequentially. The enzymes contained in the enzyme membranes should be compatible. In Comparative Example C1, the anti-interference membranes were prepared in step S1 of Comparative Example B1 by using chitosan (CS) at mass ratios of 0.25%, 0.5%, and 1% in the mixed solution, resulting in three types of CS membranes. Similarly, in Comparative Example C2, the anti-interference membranes were prepared in step S1 of Comparative Example B2 by using Nafion at mass ratios of 0.25%, 0.5%, and 0.1% in the mixed solution, resulting in three types of anti-interference membranes. Since the solvent evaporates after drying, the final anti-interference membranes of Comparative Examples C1 and C2 do not contain solvent. The test results are shown in Table 1. The SIR in Table 1 is the ratio of the measured H2O2 current to the measured current of the interfering components, which can reflect the anti-interference effect on these interfering components.

[0142] Table 1

[0143]

[0144] As can be seen from Table 1, compared with the test results of chitosan membrane, Nafion membrane and no membrane, the current of UA, AA and AC of the anti-interference membrane of Example C3 are significantly reduced, indicating that the anti-interference membrane of Example C3 can effectively isolate the UA, AA and AC interfering components in human body fluids and improve the accuracy. Combining the current data with the SIR data, it can be seen that the anti-interference effect of the anti-interference membrane of this application is more than 30 times that of Nafion membrane and more than 60 times that of chitosan membrane.

[0145] 5.3 Testing the anti-interference effect of H2O2

[0146] The electrochemical sensor of Example C3 was subjected to an anti-interference test for detecting H2O2. The steps included: turning on the electrochemical sensor and continuously recording the time; placing the sensor's detection end in a 10 μM H2O2 solution and recording the current; then, adding common interfering components found in bodily fluids to the solution sequentially, resulting in the following concentrations: 100 μM ascorbic acid (AA), 100 μM citric acid (CA, anionic), 100 μM fructose-lactose or galactose (Fru, neutral molecule), 100 μM microalbumin (Mal, neutral molecule), 100 μM CaCl2, 10 μM acetaminophen (AC, neutral molecule), and 100 μM uric acid (UA, anionic); finally, adding H2O2 to bring the H2O2 concentration to 20 μM. The time and current results were then recorded. Figure 2 In the figure, 10 μM and 100 μM are the changes in solution concentration, i.e., the variable delta Δ.

[0147] according to Figure 2 As can be seen, the electrochemical sensor with the anti-interference membrane of this application can detect hydrogen peroxide with high sensitivity. Only hydrogen peroxide produces a signal, while other substances do not. Moreover, the concentration of interfering components is much higher than that of H2O2, but this does not affect the detection results. Therefore, the interference of various substances such as AA, CA, and Fru in body fluids can be eliminated during detection, which meets the requirements of commercial applications.

[0148] 5.4 Sensitivity for creatine detection

[0149] The sensitivity of the electrochemical sensor C3 in Example C3 for detecting sarcosine (Sar) was tested. The enzyme in the enzyme membrane was sarcosine oxidase. The steps included: turning on the electrochemical sensor and continuously recording the time; placing the sensor's detection end in a 1 μM Sar solution and recording the current; then adding Sar multiple times, increasing the solution concentration by 5 μM each time (the variable delta Δ). Finally, the time and current results were recorded as follows. Figure 3 Note that the current unit in the diagram is μA, not nA. Here, 1 μA = 10 nA. 3nA.

[0150] according to Figure 3 The sarcosine electrochemical sensor prepared using this membrane already showed a relatively strong current signal for 1 μM sarcosine. Each time the sarcosine concentration was increased, the current signal changed abruptly, thus enabling highly sensitive detection of sarcosine.

[0151] Plotting the solution concentration against the current yields... Figure 4 Note that the current unit in the diagram is μA, and R in the diagram... 2 The figure represents the variance of the linear fit. This figure illustrates the linear relationship between the solution and the current, further demonstrating the sensitivity and accuracy of the sensor.

[0152] 5.5 Anti-interference effect of creatine detection

[0153] An anti-interference test was conducted on the electrochemical sensor of Example C3 for detecting sarcosine (Sar). The enzyme membrane contained only sarcosine oxidase. The steps included: turning on the electrochemical sensor and continuously recording the time; placing the sensor's detection end in a Sar solution and recording the current; then sequentially adding common interfering components found in body fluids to the solution, making the solution concentrations 100 μM AA, 100 μM CA, 100 μM Fru, 100 μM Mal, 100 μM CaCl2, 100 μM AC, and 100 μM UA, respectively; finally, Sar was added to make the Sar concentration 20 μM. The time and current results were then recorded. Figure 5 In the figure, 10 μM and 100 μM are the changes in solution concentration, i.e., the variable delta Δ.

[0154] according to Figure 5 As can be seen, the electrochemical sensor with the anti-interference membrane of this application can detect sarcosine with high sensitivity. Only sarcosine has a signal, and other substances do not generate signals. Moreover, the concentration of interfering components is much higher than that of sarcosine, but this does not affect the detection results. Therefore, the interference of various substances such as AA, CA, and Fru in body fluids can be eliminated during detection, which meets the requirements of commercial applications.

[0155] In summary, the anti-interference materials and anti-interference films of the embodiments of this application, and their application in electrochemical sensing technology, can effectively isolate interfering components, improve the detection accuracy of target substances, reduce detection time, and increase detection sensitivity.

[0156] 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. An electrochemical sensor, characterized in that, It includes an anti-interference membrane, an electrode, and an enzyme membrane, wherein the anti-interference membrane is disposed between the electrode and the enzyme membrane, and the anti-interference membrane is attached to the electrode and the enzyme membrane; or The enzyme membrane is disposed between the electrode and the anti-interference membrane, and the enzyme membrane is attached to the electrode and the anti-interference membrane; The anti-interference membrane is used to isolate anionic and neutral molecular interference components, and the materials contained in the anti-interference membrane include anti-interference materials and adhesives; The anti-interference material includes carboxylated materials, and the carboxylated materials include at least one of carboxylated materials containing conjugated π bonds and carboxylated molecular sieves; The carboxylated material containing conjugated π bonds includes at least one of carboxylated graphene, carboxylated carbon nanotubes, and carboxylated metal-organic framework materials. The method for preparing the anti-interference film includes the following steps: First, the anti-interference material and the binder are mixed to form a mixed slurry, and then the mixed slurry is subjected to film formation treatment.

2. The electrochemical sensor according to claim 1, characterized in that, The carboxyl functional groups contained in the carboxylated material account for 0.001% to 30% of the mass of the carboxylated material; and / or The pore size of the carboxylated molecular sieve is 0.3 nm to 50 nm.

3. The electrochemical sensor according to claim 1 or 2, characterized in that, The anti-interference material also includes materials containing conjugated π bonds, wherein the materials containing conjugated π bonds do not contain carboxyl groups.

4. The electrochemical sensor according to claim 3, characterized in that, The material containing conjugated π bonds includes at least one of carbon nanotubes, graphene, C60, graphite, and metal-organic framework materials; and / or The mass ratio of the carboxylated material to the material containing conjugated π bonds is (1-95):(5-99).

5. The electrochemical sensor according to claim 1, characterized in that, The adhesive comprises at least one of gum arabic, perfluorosulfonic acid resin, chitosan, polyurethane, and polyethylene; and / or The mass ratio of the anti-interference material to the adhesive is (10-99):(1-90).

6. The electrochemical sensor according to claim 1, characterized in that, The electrode material includes any one of noble metals, glassy carbon, and graphite, and The enzyme membrane contains any one of glucose oxidase, sarcosine oxidase, cholesterol oxidase, and pyruvate oxidase; or The anti-interference membrane is disposed between the electrode and the enzyme membrane, and the anti-interference membrane is attached to the electrode and the enzyme membrane. The enzyme membrane contains urate oxidase or ascorbate oxidase.

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