Polymer coating distance sensor and preparation method and detection method thereof

Abstract

The present invention belongs to the field of microfluidic analysis and detection technology, and relates to a polymer-coated sensor and a preparation method and a detection method thereof. It includes: a functionalized membrane layer, which is formed by a polymer and a filter membrane, the setting of the polymer can prevent a solution without a target from penetrating from one side of the functionalized membrane layer through the filter membrane to the other side of the functionalized membrane layer, and the target can specifically cut off the chain of the polymer; a capillary membrane layer, which is a membrane material with a capillary effect and has an elongated strip structure; the functionalized membrane layer is arranged at one end of the capillary membrane layer, and the functionalized membrane layer is in contact with the capillary membrane layer, so that a part of the capillary membrane layer is covered by the functionalized membrane layer, the functionalized membrane layer serves as a receiving area for the object to be detected, and another part of the capillary membrane layer not covered by the functionalized membrane layer serves as a detection result area. The present invention has the advantages of being simple and portable, rapid and sensitive, and not requiring special instruments and complex preparation steps.

Description

Technical Field

[0001] The invention belongs to the technical field of microfluidic analysis and detection, and relates to a polymer-coated sensor and a preparation method and a detection method thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] The visual quantitative detection method based on distance change can achieve quantitative detection of the target content by simply measuring the change in distance. This method usually requires the stimulus-responsive polymer to change its molecular structure or state after external stimulation, thereby affecting its physical and chemical properties. However, the inventors have found that the materials used in this method usually require repeated washing and labeling of encapsulated molecules or nanoparticles, and have the disadvantages of complex preparation steps, slow response speed, poor stability, low sensitivity, and expensive instruments. Summary of the invention

[0004] In order to solve the deficiencies of the prior art, the purpose of the present invention is to provide a polymer-coated sensor and a preparation method and a detection method thereof, which have the advantages of being simple and portable, rapid and sensitive, and not requiring special instruments and complicated preparation steps.

[0005] In order to achieve the above object, the technical solution of the present invention is:

[0006] In one aspect, a polymer-coated sensor comprises:

[0007] The functionalized membrane layer is formed by a composite of a polymer and a filter membrane. The setting of the polymer can prevent a solution without a target from penetrating from one side of the functionalized membrane layer through the filter membrane to the other side of the functionalized membrane layer. The target can specifically cut the chain of the polymer.

[0008] The capillary film layer is a film layer material with a capillary effect and has a long and thin strip structure;

[0009] The functionalized membrane layer is arranged at one end of the capillary membrane layer, and the functionalized membrane layer contacts the capillary membrane layer, so that a part of the capillary membrane layer is covered by the functionalized membrane layer, and the functionalized membrane layer serves as a receiving area for the object to be detected, and another part of the capillary membrane layer not covered by the functionalized membrane layer serves as a detection result area.

[0010] When the target solution is added to the receiving area of ​​the object to be detected, the target solution contacts the polymer in the functionalized membrane layer, specifically cuts off the polymer chain, increases the permeability of the functionalized membrane layer, and causes the solution to flow longitudinally from top to bottom. Since the functionalized membrane layer contacts the capillary membrane layer, the solution enters the capillary membrane layer. Under the action of the capillary effect, the solution enters the capillary membrane layer and flows horizontally from one end of the capillary membrane layer to the other end, thereby showing a flowing water mark in the detection result area. Due to the different specific cutting efficiencies of the polymer chains in the functionalized membrane layer for the target of different concentrations, the permeability change rate of the functionalized membrane layer is different. The higher the cutting efficiency, the stronger the permeability of the functionalized membrane layer, resulting in different rates of longitudinal seepage of the solution. At the same time, the amount of target solution added to the receiving area of ​​the object to be detected is small (e.g., 1 drop, 2 drops, 3 drops, etc.), and the volatilization rate of the solvent is unchanged, so that the length of the solution flow trace (e.g., flowing water mark) in the detection result area is different. Based on this, according to the different lengths of the flowing water mark, the target solution can be more easily quantitatively analyzed. When there is no target in the solution, the polymer chain cannot be specifically cut off, and the permeability of the functionalized membrane layer remains unchanged, thereby preventing the solution from flowing vertically from top to bottom, and thus no trace of solution flow can be displayed in the test result area, thus achieving qualitative analysis of the target solution.

[0011] During detection, the solution may flow to the capillary membrane layer, avoiding longitudinal seepage and directly flowing horizontally in the capillary membrane layer, resulting in inaccurate detection. In order to solve this problem, the sensor of the present invention also includes a sample cover, the sample cover is provided with a sample adding groove, the bottom of the sample adding groove is open, and the bottom of the sample adding groove is tightly fitted with the functionalized membrane layer.

[0012] In order to ensure that the bottom of the sample loading groove fits tightly with the functionalized membrane layer, the sensor of the present invention also includes a base, which has a groove, and the groove is used to place the functionalized membrane layer and the capillary membrane layer. After the groove is assembled with the sample cover, the bottom of the sample loading groove fits tightly with the functionalized membrane layer.

[0013] On the other hand, a method for preparing the above polymer coated sensor comprises the following steps:

[0014] Compounding the polymer with the filter membrane to form a functionalized membrane layer;

[0015] Providing a film layer material having an elongated strip structure and a capillary effect as a capillary film layer;

[0016] The functionalized membrane layer is arranged at one end of the capillary membrane layer, and the functionalized membrane layer is closely attached to the capillary membrane layer.

[0017] In a third aspect, a detection method using the above-mentioned polymer coated sensor is provided, wherein a solution of the object to be detected is added to the object to be detected receiving area of ​​the polymer coated sensor, followed by incubation, and then the length or area of ​​the solution flow trace in the detection result area is measured, and a qualitative and / or quantitative analysis is performed on the target object based on the length or area of ​​the solution flow trace.

[0018] Since the above detection method is based on the degradation activity of the target on the polymer, and the inhibitor can reduce the degradation activity of the target on the polymer, the fourth aspect is the use of a sensor coated with the above polymer in detecting the target inhibitor.

[0019] In a fifth aspect, a detection kit comprises the above-mentioned polymer-coated sensor and a buffer solution.

[0020] The beneficial effects of the present invention are:

[0021] 1. The functionalized membrane layer formed by the composite of polymer and filter membrane is assembled to one end of the capillary membrane layer. After the target object specifically degrades the polymer, the permeability of the functionalized membrane layer changes, the longitudinal seepage of the solution is realized, and the solution enters the capillary membrane layer. Through the capillary action of the capillary membrane layer, the solution flows laterally in the capillary membrane layer. The rate of change of the permeability of the functionalized membrane layer is affected by the concentration of the target object. Combined with the volatilization rate of the solution with a smaller volume, the distances of the lateral flow of targets of different concentrations in the capillary membrane layer are different, that is, the flow traces of the solution are different. Therefore, the target object can be qualitatively analyzed by the presence or absence of the solution flow trace, and the target object can be quantitatively analyzed according to the distance of the solution flow trace. The method has the advantages of being simple and convenient, user-friendly, low-cost, rapid and sensitive.

[0022] 2. The integrated, distance-based sensor constructed by the present invention can meet the on-site rapid detection requirements of "sample in, result out", and uses a small number of reagents (only two substances that can produce stimulus responses, such as enzymes and enzymatic substrates), does not require labeling and special instruments, and is not easily interfered by complex sample matrix effects.

[0023] 3. The present invention proposes to construct a distance-based sensor and use it for rapid and sensitive detection of target objects. This method can avoid the use of expensive instruments, large amounts of reagent consumption, and repeated flushing and calibration, and has the advantages of low cost, recyclability, and disposable use. The distance-based measurement method can be used to detect biomarkers, quickly diagnose the condition, and has broad application prospects in emergency treatment and home care. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0025] Figure 1 It is a schematic diagram of the structure of a sensor with a polymer coating according to a typical embodiment of the present invention;

[0026] Figure 2 It is a schematic diagram of a top view of a polymer-coated sensor according to a typical embodiment of the present invention;

[0027] Figure 3 It is a schematic diagram of the structure of the sample cover in a specific embodiment of the present invention;

[0028] Figure 4 A cross-sectional view of a sample cover in a specific embodiment of the present invention

[0029] Figure 5 It is a structural schematic diagram of a base in a specific implementation manner of the present invention;

[0030] Figure 6 A cross-sectional view of a base in a specific embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the principle of using a sensor for detection according to Embodiment 1 of the present invention;

[0032] Figure 8 This is a screening diagram of the microporous filter membrane of Example 1 of the present invention;

[0033] Fig. 9 This is a diagram of the assembly of the sensor according to Example 1 of the present invention;

[0034] Fig.10 This is a graph showing the results of detecting α-amylase in Example 1;

[0035] Among them, 1. functionalized membrane layer, 2. capillary membrane layer, 3. sample cover, 4. sample loading slot, 5. base, 6. groove, 7. starch coating membrane, 8. pH test strip. DETAILED DESCRIPTION

[0036] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0037] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0038] In view of the disadvantages of the sensors used in the existing distance change-based visual quantitative detection methods, such as complex preparation, slow response speed, low stability and sensitivity, and expensive instruments, the present invention provides a polymer-coated sensor and a preparation method and detection method thereof.

[0039] A typical embodiment of the present invention provides a polymer-coated sensor, such as Figures 1-2 As shown, including:

[0040] The functionalized membrane layer 1 is formed by a composite of a polymer and a filter membrane. The setting of the polymer can prevent a solution without a target from penetrating from one side of the functionalized membrane layer through the filter membrane to the other side of the functionalized membrane layer. The target can specifically cut the chain of the polymer.

[0041] The capillary film layer 2 is a film layer material with a capillary effect and has a long and thin strip structure;

[0042] The functionalized membrane layer 1 is arranged at one end of the capillary membrane layer 2, and the functionalized membrane layer 1 is in contact with the capillary membrane layer 2, so that a portion of the capillary membrane layer 2 is covered by the functionalized membrane layer 1, and the functionalized membrane layer 1 serves as a receiving area for the object to be detected, and another portion of the capillary membrane layer 2 not covered by the functionalized membrane layer 1 serves as a detection result area.

[0043] In the sensor provided by the present invention, the target solution first flows longitudinally from the functionalized membrane layer into the capillary membrane layer, and then flows transversely in the capillary membrane layer, thereby leaving a solution flow trace in the capillary membrane layer. At the same time, the concentration of the target solution affects the change rate of the permeability of the functionalized membrane layer, and combined with the volatilization of the lower target solution, the length or distance of the solution flow trace left by target solutions of different concentrations on the capillary membrane layer can be different, thereby achieving qualitative and quantitative analysis of the target.

[0044] The capillary membrane layer with a slender strip structure can ensure a more stable directional movement of the solution, thereby ensuring the accuracy and stability of the detection.

[0045] In some embodiments of this embodiment, a sample cover 3 is also included, such as Figures 3-4 As shown, the sample cover 3 is provided with a sample adding slot 4, the bottom of which is open and closely fits the functionalized membrane layer, so that the solution can firstly flow longitudinally and then flow transversely, further ensuring the detection accuracy.

[0046] In some embodiments of this embodiment, a base 5 is also included, such as Figures 5-6As shown, the base 5 is provided with a groove 6, and the groove 6 is used to place the functionalized membrane layer and the capillary membrane layer. After the groove 6 is assembled and matched with the sample cover 3, the bottom of the sample loading groove 4 is closely fitted with the functionalized membrane layer. The groove 6 and the sample cover can be plugged in by interference fit to ensure that the bottom of the sample loading groove 4 is closely fitted with the functionalized membrane layer, or can be threaded to ensure that the bottom of the sample loading groove 4 is closely fitted with the functionalized membrane layer, and a snap-fit ​​structure can also be provided to ensure that the bottom of the sample loading groove 4 is closely fitted with the functionalized membrane layer. In order to more intuitively display the length of the solution flow trace, specifically, the base 5 is provided with a scale, and the scale is matched with the capillary membrane layer.

[0047] Since the target object to be detected basically needs to be dissolved in water or an aqueous solution. Therefore, the capillary membrane layer is generally absorbent paper, which usually has excellent water absorption performance. Common absorbent materials for preparing paper bases can be: cotton pulp product paper, wood pulp product paper, bamboo pulp product paper, straw pulp product paper, fiber paper, natural polymer (starch, cellulose) grafted modified absorbent paper, polyacrylic acid series absorbent paper, polypropylene resin series absorbent paper, polyvinyl alcohol series absorbent paper, polyethylene oxide absorbent paper, etc. In order to facilitate manufacturing, the present invention uses pH test paper as the capillary membrane layer, and the processing process is simpler.

[0048] In some embodiments of this embodiment, the material of the filter membrane includes but is not limited to polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), mixed cellulose ester (MCE), polyethersulfone (PES), and polypropylene (PP). Since the functionalized membrane layer is formed by a composite of a polymer and a filter membrane, the composite process is to form a polymer solution from the polymer and then composite it with the filter membrane. It is necessary to add or drip the target solution during detection. Therefore, the actual detection requires secondary humidification (or secondary use) of the filter membrane, and the properties of the secondary use filter membrane affect the performance of the sensor. The present invention preferably uses a polytetrafluoroethylene filter membrane, and the performance of the sensor formed using the polytetrafluoroethylene filter membrane is better.

[0049] The polymer and the filter membrane can be combined to form a functionalized membrane layer by forming a polymer membrane layer on one side of the filter membrane or on both sides of the filter membrane. The filter membrane can also be immersed in a polymer solution or coated with a polymer solution to allow the polymer to block the micropores in the filter membrane. When the immersion method is adopted, the pore size of the filter membrane can be 0.1 to 1.0 μm; the pore size of the filter membrane affects the blocking efficiency of the polymer. Studies have shown that the filter membrane with a pore size of 0.3 to 0.6 μm can be blocked more tightly by the polymer.

[0050] When a polymer membrane layer is formed on one side of the filter membrane, after the functionalized membrane layer and the capillary membrane layer are assembled, the layered structure can be polymer membrane layer, filter membrane, capillary membrane layer, or filter membrane, polymer membrane layer, capillary membrane layer.

[0051] Different polymers can detect different targets. For example, when the detection target is amylase, the polymer is starch; when the detection target is hyaluronidase, the polymer is hyaluronic acid; when the detection target is trypsin, the polymer is gelatin; when the detection target is DNA shearing enzyme, the polymer is DNA hydrogel; when the detection target is glucose oxidase, the polymer is glucose hydrogel; when the detection target is glutathione, the polymer is thiol hydrogel; when the detection target is β-glucuronidase, the polymer is β-glucuronic acid hydrogel; when the detection target is Ca 2+ When the polymer is sodium alginate.

[0052] Another embodiment of the present invention provides a method for preparing the above-mentioned polymer coating sensor, comprising the following steps:

[0053] Compounding the polymer with the filter membrane to form a functionalized membrane layer;

[0054] Providing a film layer material having an elongated strip structure and a capillary effect as a capillary film layer;

[0055] The functionalized membrane layer is arranged at one end of the capillary membrane layer, and the functionalized membrane layer is closely attached to the capillary membrane layer.

[0056] In some examples of this embodiment, a polymer solution is coated on the surface of the filter membrane and dried to form a functionalized membrane layer. Studies have shown that the concentration and volume of the polymer solution affect the detection performance during the coating process. When the concentration of the polymer solution is higher than 4wt%, the detection performance of the sensor is better, for example, 4 to 6wt%. When the volume of the polymer solution is not less than 15μL, the detection performance of the sensor is better, for example, 15 to 20μL.

[0057] A third embodiment of the present invention provides a detection method using the above-mentioned polymer coated sensor, wherein a solution of the object to be detected is added to the object to be detected receiving area of ​​the polymer coated sensor, and then incubated, and then the length or area of ​​the solution flow trace in the detection result area is measured, and a qualitative analysis and / or quantitative analysis of the target object is performed based on the length or area of ​​the solution flow trace.

[0058] When the length of the solution flow trace cannot be determined, for example, the capillary membrane layer is wide, and the solution flow trace is not a straight line in the width direction, but a curved line, then the area can be used for quantitative analysis. The area can be calculated through photos and PS software.

[0059] When the target to be detected is an enzyme, its optimal enzyme activity temperature is 30-40° C., so in some examples of this embodiment, the incubation temperature is 30-40° C. At this time, the evaporation rate of water in the test solution can better match the rate of polymer degradation by the target, thereby further improving the detection performance.

[0060] When the target substance to be detected is an inorganic ion, the incubation temperature is not restricted.

[0061] Since the above detection method is based on the degradation activity of the target on the polymer, and the inhibitor can reduce the degradation activity of the target on the polymer, the fourth embodiment of the present invention provides an application of the above polymer coated sensor in detecting the target inhibitor.

[0062] A fifth embodiment of the present invention provides a detection kit, comprising the above-mentioned polymer-coated sensor and a buffer solution.

[0063] Specifically, the buffer solution includes but is not limited to phosphate buffered saline (PBS Buffer), phosphate buffered saline (Tween-20) (PBST Buffer), tris (hydroxymethyl) aminomethane buffer (Tris Buffer), tris (hydroxymethyl) methylglycine buffer (Tricine Buffer), 3-morpholinepropanesulfonic acid (MOPS Buffer), 4-hydroxyethylpiperazineethanesulfonic acid buffer (HEPES Buffer), 2-(N-morpholine)ethanesulfonic acid buffer (MES Buffer), piperazine-1,4-diethanesulfonic acid buffer (PIPES Buffer), tris (hydroxymethyl) aminomethane / acetic acid / ethylenediaminetetraacetic acid (TEABuffer).

[0064] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0065] Example 1

[0066] This embodiment uses starch gelatinized liquid as the coating layer of the polymer coating film. Figure 7 The detection principle shown in the figure successfully realizes the detection of α-amylase. The specific operation steps are as follows:

[0067] Step 1: Optimal selection of microporous membrane:

[0068] like Figure 8As shown, a 5 cm diameter microporous filter membrane with different pore sizes (0.1, 0.2, 0.45, 0.8 μm) and different materials (polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), mixed cellulose ester (MCE), polyethersulfone (PES), polypropylene (PP)) was selected, 20 μL of pure aqueous solution was dripped on the central area of ​​the above different microporous filter membranes, the diffusion of the aqueous solution on the microporous filter membrane was observed, and the microporous filter membrane with the largest diffusion area was selected; after the above microporous filter membrane was dried, the appearance of the microporous filter membrane was observed, and a microporous filter membrane with stable morphology, no curling, and not easy to break was selected; 20 μL of pure aqueous solution was continued to be dripped into the central area of ​​the dried microporous filter membrane, and the effect of the microporous filter membrane on the diffusion of the aqueous solution during the second wetting was observed, and a microporous filter membrane with the same diffusion phenomenon as the first time and unchanged hydrophilic and hydrophobic properties was selected for the next step of detection. The diffusion area of ​​aqueous solution on microporous filter membranes made of polyvinylidene fluoride (PVDF), mixed cellulose ester (MCE), polyethersulfone (PES), polypropylene (PP) and other materials is small, and some of the above microporous filter membranes cannot maintain a good morphology after drying, which affects the secondary use; in the secondary wetting test, the hydrophilicity of some of the above microporous filter membranes changes. After the above screening, the microporous filter membrane made of polytetrafluoroethylene (PTFE) was finally selected. Among the polytetrafluoroethylene (PTFE) microporous filter membranes with different pore sizes, the microporous filter membranes with pore sizes of 0.1 and 0.2μm are more tightly blocked by polymers, which reduces the efficiency of target decomposition and penetration; the microporous filter membrane with a pore size of 0.8μm is not easily blocked by polymers, which affects the preparation of polymer coated membranes. In summary, a microporous filter membrane made of polytetrafluoroethylene (PTFE) with a pore size of 0.45μm was selected as the material for preparing polymer coated membranes.

[0069] Step 2: Assembly of test strips

[0070] Use a circular cutter to cut the microporous filter membrane into a 1cm diameter disc, and use a paper cutter to cut the pH test strip into a size of 5mm×60mm. Place the cut pH test strip on the lower layer, and place the microporous filter membrane in the center of the pH test strip, keeping one end aligned, and the test strip is assembled.

[0071] Step 3: Design and assembly of paper-based sensors:

[0072] The sample cover and base were drawn using 3D MAX drawing software, and the sample cover and base were printed using 3D printing technology. The sample cover, base and test paper were assembled to construct a paper-based α-amylase sensor with a specific distance. The groove on the base is the placement area for the test paper and the flow area for the liquid. The sample cover is completely embedded with one end of the base, so that the polymer coating film and the pH test paper strip are tightly combined.

[0073] Step 4: Optimization of starch concentration and drop volume

[0074] Starch solutions of different concentrations (2wt%, 4wt%, 6wt%, 8wt%, 10wt%) were prepared using 10mM, pH=7.0 phosphate buffer (PBS), incubated at 95°C for 5min, and after sufficient gelatinization, a certain volume (10μL, 11μL, 12μL, 13μL, 14μL, 15μL) of the above starch gelatinized solution was uniformly coated on a microporous filter membrane with a diameter of 1cm, and dried in an oven at 50°C for 10min to completely dry the starch gelatinized solution on the microporous filter membrane to obtain a starch coated film.

[0075] The starch coating film prepared above is assembled into the paper-based sensor described in step 3, 40 μL PBS solution is added to the sample loading groove, and the sensor is placed on a 37°C heating plate for thermal incubation for 15 minutes to observe whether PBS can penetrate through, and a group of preparation parameters that completely block PBS penetration are selected. Then, based on this condition, 40 μL, 100 U / mL α-amylase solution is added to the sample loading groove, and the sensor is placed on a 37°C heating plate for thermal incubation to observe whether the α-amylase solution can penetrate through. If penetration occurs, the degree of penetration of the solution on the polymer coating film can be judged by the lateral flow of the solution on the test paper, and then the solution outflow time is compared to select the preparation parameters of the group with the longest solution flow distance and the earliest outflow time. After screening, on the coating film prepared with different concentrations of starch, the coating concentrations of 2wt% and 4wt% cannot prevent the penetration of PBS, and the concentrations between 4wt% and 6wt% are continuously optimized, and finally the coating concentration of 5wt% is selected, which can not only prevent the penetration of PBS, but also help to reduce the detection limit of α-amylase. Similarly, the coating volumes of 10 μL, 11 μL, 12 μL, 13 μL, and 14 μL were too small to fully block the micropores and cause PBS penetration, so 15 μL was finally selected as the coating volume.

[0076] Step 5: Sample testing:

[0077] A 5 wt% starch solution was prepared using 10 mM PBS, pH = 7.0, and incubated at 95°C for 5 min. After sufficient gelatinization, 15 μL was evenly coated on a microporous filter membrane with a diameter of 1 cm, and dried in an oven at 50°C for 10 min.

[0078] Assemble the α-amylase paper-based sensor using the sample cover 3, the base 5, the starch coating film 7, and the pH test paper strip 8, as shown in FIG. Fig. 9 shown.

[0079] A series of different concentrations (10 2 , 10, 10 -1 , 10 -2 , 10 -3 , 10-4 U / mL) of α-amylase solution.

[0080] Take 40 μL of amylase solution and add it to the sample cap; as a control group, add an equal volume of aqueous solution. Place the sensor on a 37°C heating plate for thermal incubation for 15 minutes.

[0081] After waiting for 15 minutes, take a photo with your mobile phone to record the flow of the solution on the paper-based α-amylase sensor. Fig.10 shown.

[0082] Use Photoshop and other software to perform pixel analysis on images and accurately count the length of water marks.

[0083] The principle of this embodiment is that the degree to which α-amylase dissolves the starch coating layer is positively correlated with the content of α-amylase. The greater the concentration of α-amylase, the more pores are generated in the starch coating layer, and the more liquid in the sample loading slot penetrates through these pores to the bottom pH test strip, thereby leaving a longer water mark on the pH test strip. When amylase is not present or the content is extremely low, the polymer coating film remains intact, and the liquid in the sample loading slot cannot penetrate to the bottom layer, and no water mark is generated on the pH test strip.

[0084] Embodiment 2:

[0085] Based on the same device and principle as in Example 1, enzyme inhibitors can be added to the enzyme solution to detect the enzyme inhibitors. For example, when acarbose and α-amylase are present at the same time, the activity of α-amylase is inhibited, the starch coating film is not destroyed or is destroyed to a low degree, and the solution does not flow on the test paper or flows a short distance.

[0086] Embodiment 3:

[0087] Based on the same device and principle as in Example 1, the detection object is replaced with hyaluronidase, and the polymer coating film is replaced with a hyaluronic acid coating film, and a paper-based hyaluronidase sensor is constructed to detect hyaluronidase.

[0088] Embodiment 4:

[0089] Based on the same device and principle as in Example 1, the detection object is replaced by trypsin, and the polymer coating membrane is replaced by a gelatin coating membrane, and a paper-based trypsin sensor is constructed to detect trypsin.

[0090] Embodiment 5:

[0091] Based on the same device and principle as in Example 1, the detection object is replaced with DNA shearing enzyme, and the polymer coating membrane is replaced with DNA hydrogel, so as to construct a paper-based DNA shearing enzyme sensor to realize the detection of DNA shearing enzyme.

[0092] Embodiment 6:

[0093] Based on the same device and principle as in Example 1, the detection object is replaced by glucose oxidase, and the polymer coating film is replaced by glucose hydrogel, and a paper-based glucose oxidase sensor is constructed to detect glucose oxidase.

[0094] Embodiment 7:

[0095] Based on the same device and principle as in Example 1, the detection object is replaced with glutathione, and the polymer coating membrane is replaced with thiol hydrogel, so as to construct a paper-based glutathione sensor to realize the detection of glutathione.

[0096] Embodiment 8:

[0097] Based on the same device and principle as in Example 1, the detection object is replaced with β-glucuronidase, and the polymer coating membrane is replaced with β-glucuronic acid hydrogel. A paper-based β-glucuronidase sensor is constructed to detect β-glucuronidase and further detect Escherichia coli.

[0098] Embodiment 9:

[0099] Based on the same device and principle as in Example 1, the detection substance was replaced with Ca 2+ , the coating membrane was replaced with sodium alginate, in the presence of Ca 2+ In the presence of Ca, sodium alginate undergoes cross-linking to form a hydrogel. 2+ The higher the content of the hydrogel, the tighter the cross-linking structure of the hydrogel, which leads to the blocking of the filter membrane, forming the opposite flow law to the above-mentioned Examples 1-8, and constructing the paper-based Ca 2+ The sensor can detect Ca 2 + Detection.

[0100] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A polymer-coated sensor, characterized in that: include: The functionalized membrane layer is formed by a composite of a polymer and a filter membrane. The setting of the polymer can prevent a solution without a target from penetrating from one side of the functionalized membrane layer through the filter membrane to the other side of the functionalized membrane layer. The target can specifically cut the chain of the polymer. The capillary film layer is a film layer material with a capillary effect and has a long and thin strip structure; The functionalized membrane layer is arranged at one end of the capillary membrane layer, and the functionalized membrane layer contacts the capillary membrane layer, so that a part of the capillary membrane layer is covered by the functionalized membrane layer, the functionalized membrane layer serves as a receiving area for the object to be detected, and another part of the capillary membrane layer not covered by the functionalized membrane layer serves as a detection result area; The material of the filter membrane is selected from polytetrafluoroethylene, polyvinylidene fluoride, mixed cellulose ester, polyether sulfone or polypropylene; The polymer and the filter membrane are composited to form a functionalized membrane layer by immersing the filter membrane in a polymer solution or coating the filter membrane with a polymer solution, and the filter membrane has a pore size of 0.3-0.6 μm.

2. The polymer-coated sensor according to claim 1, characterized in that: It also includes a sample cover, wherein the sample cover is provided with a sample adding groove, the groove bottom of the sample adding groove is open, and the groove bottom of the sample adding groove is closely fitted with the functionalized film layer; It also includes a base, which has a groove for placing the functionalized membrane layer and the capillary membrane layer. After the groove is assembled with the sample cover, the bottom of the sample loading groove fits tightly with the functionalized membrane layer. The base is provided with a scale, which matches the capillary membrane layer.

3. A method for preparing a polymer-coated sensor according to claim 1 or 2, characterized in that: The steps include: Compounding the polymer with the filter membrane to form a functionalized membrane layer; Providing a film layer material having an elongated strip structure and a capillary effect as a capillary film layer; The functionalized membrane layer is arranged at one end of the capillary membrane layer, and the functionalized membrane layer is closely attached to the capillary membrane layer.

4. The method for preparing a polymer-coated sensor according to claim 3, characterized in that: The polymer solution is coated on the surface of the filter membrane and formed into a functionalized membrane layer after drying; the concentration of the polymer solution is higher than 4wt%; and the volume of the polymer solution is not less than 15 μL.

5. The method for preparing a polymer-coated sensor according to claim 3, characterized in that: The concentration of the polymer solution is 4~6 wt%; the volume of the polymer solution is 15~20 μL.

6. A detection method using a sensor having a polymer coating according to claim 1 or 2, characterized in that: The analyte solution is added to the analyte receiving area of ​​the polymer-coated sensor, incubated, and then the length or area of ​​the solution flow trace in the detection result area is measured, and the target is qualitatively and / or quantitatively analyzed based on the length or area of ​​the solution flow trace.

7. The detection method according to claim 6, characterized in that: The incubation temperature is 30~40 ℃.

8. Use of a polymer-coated sensor according to claim 1 or 2 in detecting a target inhibitor.

9. The use according to claim 8, characterized in that: The target inhibitor is an enzyme inhibitor.

10. A detection kit, characterized in that: A sensor comprising the polymer coating according to claim 1 or 2 and a buffer solution.

11. The detection kit according to claim 10, characterized in that: The buffer solution is a phosphate buffer, a phosphate buffer of Tween-20, a tris(hydroxymethyl)aminomethane buffer, a tris(hydroxymethyl)methylglycine buffer, a 3-morpholinepropanesulfonic acid, a 4-hydroxyethylpiperazineethanesulfonic acid buffer, a 2-(N-morpholine)ethanesulfonic acid buffer, a piperazine-1,4-diethanesulfonic acid buffer or a tris(hydroxymethyl)aminomethane-acetic acid-ethylenediaminetetraacetic acid buffer.

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