Electrochemiluminescence sensor and preparation method thereof and application in detecting glucose

Abstract

The present invention belongs to the technical field of electrochemiluminescence sensing, and relates to an electrochemiluminescence sensor, a preparation method and an application thereof in detecting glucose. The electrochemiluminescence sensor comprises an electrochemiluminescence sensing platform and potassium persulfate, and the preparation method of the electrochemiluminescence sensing platform comprises: coprecipitating poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-thiadiazole)] (PFBT) with polystyrene-maleic anhydride copolymer (PSMA) to obtain carboxyl functionalized CPNs PFBT ‑COOH, using CPNs PFBT The electrochemiluminescence sensor provided by the present invention can simplify the steps of detecting glucose, reduce costs, and realize convenient detection of glucose.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochemiluminescence sensing, and relates to an electrochemiluminescence sensor, a preparation method and application thereof in detecting glucose. 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 inventors have found that the detection of glucose by electrochemiluminescence (ECL) sensing requires that the luminescent material be modified onto the electrode first, and then glucose oxidase (GOD) be modified onto the electrode to catalyze glucose oxidation, and the interaction between the product and the luminescent material or co-reactant affects the ECL signal intensity of the platform, thereby achieving the detection of glucose. However, it is difficult for GOD to exist stably on the electrode, so it is often necessary to introduce additional materials to assist the fixation of GOD on the electrode, which often reduces sensitivity, makes the operation steps cumbersome, and is costly. Summary of the invention

[0004] In order to address the deficiencies of the prior art, the purpose of the present invention is to provide an electrochemiluminescence sensor, a preparation method and its application in detecting glucose. The electrochemiluminescence sensor provided by the present invention can simplify the steps of detecting glucose, reduce costs, and achieve convenient detection of glucose.

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

[0006] On the one hand, a method for preparing an electrochemiluminescent sensing platform is to coprecipitate poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-thiadiazole)] (PFBT) with polystyrene-maleic anhydride copolymer (PSMA) to obtain carboxyl functionalized CPNs. PFBT -COOH, using CPNs PFBT The electrode surface is modified with -COOH.

[0007] On the other hand, an electrochemiluminescent sensor includes an electrochemiluminescent sensing platform and potassium persulfate, wherein the electrochemiluminescent sensing platform is obtained by the above preparation method.

[0008] In a third aspect, a method for preparing an electrochemiluminescent sensor includes the method for preparing the electrochemiluminescent sensing platform described above, wherein the obtained electrochemiluminescent sensing platform is used as a working electrode, and potassium persulfate is added to the working solution.

[0009] A fourth aspect provides an application of the electrochemiluminescence sensor in detecting glucose.

[0010] In a fifth aspect, a glucose detection kit comprises an electrochemiluminescent sensing platform, potassium persulfate and a buffer solution, wherein the electrochemiluminescent sensing platform is obtained by the above-mentioned preparation method.

[0011] When the electrochemiluminescent sensing platform prepared by the present invention is used as the working electrode, potassium persulfate is added to the reaction solution, CPNs PFBT After -COOH was modified on the GCE surface, CPNs PFBT -COOH will produce a stable ECL signal in the presence of potassium persulfate (K2S2O8); when glucose is added to the solution as a reactant, CPNs modified on the electrode surface PFBT -COOH has a dual role similar to GOD and catalase (HRP), catalyzing the decomposition of glucose to produce H2O2, which is then converted into H2O2 by CPNs that mimic the action of HRP enzyme. PFBT -COOH catalyzes the in-situ production of a large amount of O2, which can be used as a co-reactant to catalyze CPNs PFBT -COOH produces ECL signal, and this process is repeated, which greatly enhances the ECL signal and greatly improves the reaction sensitivity.

[0012] The beneficial effects of the present invention are:

[0013] 1. The present invention prepares the ECL material CPNs with excellent performance by co-precipitation of PFBT and PSMA PFBT -COOH.

[0014] 2. CPNs provided by the present invention PFBT -COOH, under the premise of introducing K2S2O8 as a co-reactant, can produce a strong ECL signal, and after the addition of glucose, its ECL signal is enhanced and the signal is stable. At the same time, with the increase of the amount of glucose added, the ECL signal gradually increases, thereby realizing the quantitative detection of glucose.

[0015] 3. Experiments have shown that the electrochemiluminescence sensor provided by the present invention has a -3 mol / L~1.0×10 -6 mol / L, the ECL intensity showed a good linear relationship with the logarithm of glucose concentration, and the detection limit (S / N=3) was 3.4×10 -7 mol / L, and has good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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.

[0017] Figure 1 CPNs prepared in Example 1 of the present invention PFBT -COOH observation diagram under sunlight and ultraviolet light, a is sunlight, b is ultraviolet light;

[0018] Figure 2 CPNs prepared in Example 1 of the present invention PFBT Transmission electron microscopy (TEM) images of -COOH, the scale bar in a is 1 μm, and the scale bar in b is 100 nm;

[0019] Figure 3 CPNs prepared in Example 1 of the present invention PFBT -IR spectrum of COOH;

[0020] Figure 4 CPNs constructed for Example 2 of the present invention PFBT -ECL diagram of COOH / GCE process;

[0021] Figure 5 CPNs constructed for Example 3 of the present invention PFBT -ECL performance diagram of COOH / GCE, a is the ECL-time curve, b is the CV curve, and c is the ECL-V curve;

[0022] Figure 6 CPNs constructed for Example 4 of the present invention PFBT -COOH / GCE sensing platform for glucose detection diagram, a is the concentration of glucose added to the platform (10 -2 mol / L、10 -3 mol / L、10 -4 mol / L、10 -5 mol / L、10 -6 mol / L、10 - 7 mol / L、10 -8 mol / L、10 -9 mol / L、10 -10 mol / L、10 -11 mol / L、 10 -12 mol / L、10 -13 mol / L) and CPNs PFBT -COOH / GCE ECL intensity fitting curve, b is the addition of different concentrations of glucose (10 -3 mol / L~10 -6 mol / L) when the corresponding CPNs PFBT -COOH / GCE ECL intensity, c is the glucose added to the platform (10 - 3 mol / L~10 -6 mol / L) concentration logarithm and CPNs PFBT -Linear fitting curve of the ECL intensity relationship of COOH / GCE;

[0023] Figure 7 CPNs constructed for Example 4 of the present invention PFBT -ECL stability diagram of COOH / GCE;

[0024] Figure 8 The CPNs constructed in Example 4 of the present invention PFBT -Mechanism diagram of COOH / GCE for glucose detection. DETAILED DESCRIPTION

[0025] 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.

[0026] 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.

[0027] In view of the fact that GOD is difficult to stably exist on the electrode during the existing ECL detection, which reduces sensitivity, the method used to solve this problem leads to the defects of complicated steps and high cost. The present invention proposes an electrochemiluminescence sensor, a preparation method and its application in detecting glucose.

[0028] A typical embodiment of the present invention provides a method for preparing an electrochemiluminescent sensing platform, wherein poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-thiadiazole)] (PFBT) and polystyrene-maleic anhydride copolymer (PSMA) are coprecipitated to obtain carboxyl-functionalized CPNs. PFBT -COOH, using CPNs PFBT The electrode surface is modified with -COOH.

[0029] The poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzothiadiazole)] (PFBT for short) described in the present invention is a commercial product, and its structural formula is as follows:

[0030]

[0031] In some embodiments, PFBT solution and PSMA solution are prepared respectively using organic solvents, the PFBT solution and PSMA solution are mixed, the mixture is placed in pure water under ultrasonic conditions, the organic solvent in the reaction system is blown out using nitrogen or an inert gas, and the solution is obtained after filtering.

[0032] In one or more embodiments, the organic solvent is tetrahydrofuran (THF).

[0033] In one or more embodiments, the PFBT solution and the PSMA solution are mixed by ultrasonic treatment.

[0034] In one or more embodiments, the volume ratio of the mixed liquid to pure water is 1.5-2.5:10.

[0035] In one or more embodiments, the mixed solution is placed in pure water for ultrasonic treatment for 10 to 20 minutes, and then the organic solvent is blown out.

[0036] In one or more embodiments, filtration is performed using a 0.22 μm filter.

[0037] In some embodiments, the mass ratio of PFBT to PSMA is 1:0.15-0.25.

[0038] Another embodiment of the present invention provides an electrochemiluminescent sensor, comprising an electrochemiluminescent sensing platform and potassium persulfate, wherein the electrochemiluminescent sensing platform is obtained by the above-mentioned preparation method.

[0039] A third embodiment of the present invention provides a method for preparing an electrochemiluminescent sensor, including the method for preparing the electrochemiluminescent sensing platform described above, using the obtained electrochemiluminescent sensing platform as a working electrode, and adding potassium persulfate to the working solution.

[0040] A fourth embodiment of the present invention provides a use of the electrochemiluminescence sensor described above in detecting glucose.

[0041] A fifth embodiment of the present invention provides a glucose detection kit, comprising an electrochemiluminescent sensing platform, potassium persulfate and a buffer solution, wherein the electrochemiluminescent sensing platform is obtained by the above-mentioned preparation method.

[0042] Specifically, the buffer solution is phosphate-buffered saline (PBS) buffer.

[0043] 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.

[0044] Example 1 CPNs PFBT Preparation of -COOH / GCE

[0045] CPNs PFBT Preparation of -COOH: Prepare PFBT and PSMA mother solutions (1 mg / mL) with THF, sonicate each for 15 min, take 1 mL PFBT and 200 μL PSMA, dilute to 2 mL with THF, sonicate for 20 min, and immediately pour 2 mL of the mixed solution into 10 mL ultrapure water while maintaining sonication, sonicate again for 15 min, and slowly pass N2 through a 1000 μL gun tip below the liquid surface of a small beaker at room temperature until all THF is blown out, and then filter with a 0.22 μm filter to obtain CPNs PFBT -COOH.

[0046] Figure 1 CPNs prepared in Example 1 PFBT -COOH under sunlight and UV light. It can be clearly seen from the figure that CPNs PFBT -COOH is a good yellow light emitter.

[0047] Figure 2 CPNs prepared in Example 1 PFBT -COOH morphology under TEM, it can be seen that the prepared CPNs PFBT -COOH is a spherical structure with a size of less than 100 nm that is dispersed relatively evenly.

[0048] Figure 3 CPNs prepared in Example 1 PFBT -COOH infrared spectrum. It can be clearly seen from the figure that CPNs PFBT -COOH has an obvious -COOH peak at 1635, proving the existence of -COOH.

[0049] Example 2 CPNs PFBT -COOH / GCE construction

[0050] Before modifying the electrode, the GCE was pretreated, polished and cleaned. First, the GCE surface was polished in the shape of "8" using three different particle sizes of Al2O3 powder, 1.0μm, 0.3μm and 0.05μm, on the suede. Each particle size of Al2O3 powder was polished 100 times until the surface of the GCE was bright. Then the residual Al2O3 powder on the GCE was rinsed with ultrapure water, and then it was ultrasonically cleaned three times in a centrifuge tube filled with ultrapure water, each time for 3 minutes. After the ultrapure water cleaning was completed, it was transferred to 1:1 HNO3 and anhydrous ethanol for ultrasonic cleaning for 3 minutes. After the acid and alcohol washing was completed, it was ultrasonically cleaned again in a centrifuge tube filled with ultrapure water for three times, each time for 3 minutes. The GCE treated above was like a mirror, and finally the GCE was blown dry with N2 for use. Then take 8μL of the prepared CPNs PFBT -COOH solution was dripped onto the pretreated GCE surface for drop coating. Then the modified GCE surface was allowed to dry naturally at room temperature to obtain CPNs. PFBT -COOH / GCE.

[0051] Figure 4 Construction of CPNs for Example 2 PFBT -COOH / GCE process, it can be clearly seen that in the absence of K2S2O8, CPNs PFBT -COOH / GCE has a weak ECL signal. However, in the presence of K2S2O8, PFBT A strong ECL signal was observed on -COOH / GCE. In addition, in PBS buffer (pH 7.4) containing 0.15 mol / L K2S2O8, the ECL signal observed on bare GCE was much lower than that on CPNs. PFBT -COOH / GCE. This fact suggests that CPNs PFBT -The COOH / GCE sensing platform was completed.

[0052] Example 3 CPNs PFBT -ECL performance analysis of COOH / GCE

[0053] CPNs constructed in Example 2 PFBT -COOH / GCE was used as the working electrode, the platinum wire electrode was used as the counter electrode, and Ag / AgCl was used as the reference electrode. The three-electrode system was immersed in 0.15 mol / L K2S2O8 (0.1 mol / L PBS, pH 7.4) solution, and the CPNs were detected using Xi'an Ruimai MPI-E ECL detector. PFBT -ECL signal of COOH / GCE surface.

[0054] Figure 5 For the CPNs constructed in Example 2 PFBT -COOH / GCE platform to test ECL performance, CPNs PFBT -COOH / GCE can produce obvious ECL phenomenon in K2S2O8. When the low potential is higher than -1.2V, there is only ECL peak corresponding to oxidation, while when the low potential is lower than -1.2V, there is ECL peak corresponding to reduction. When the selected low potential is -1.6V, there is obvious ECL peak during oxidation, and a smaller ECL peak during reduction.

[0055] Example 4 CPNs PFBT -COOH / GCE for ECL detection of glucose

[0056] CPNs constructed in Example 2 PFBT -COOH / GCE was used as the working electrode, platinum wire electrode as the counter electrode, and Ag / AgCl as the reference electrode. In the presence of K2S2O8, different concentrations of glucose were added to the reaction solution to study the response of the ECL signal of the sensing platform to different concentrations of glucose. At the same time, the stability of the ECL signal when testing the glucose concentration was observed.

[0057] Figure 6 a indicates that as the concentration of glucose added to the reaction solution increases, CPNs PFBT The ECL signal of -COOH / GCE gradually increased. Figure 6 b indicates that the glucose concentration is 1.0×10 -3 mol / L~1.0×10 -6 mol / L, the ECL intensity and the logarithm of glucose concentration showed a good linear relationship. PFBT The ECL signal of -COOH / GCE was linearly fitted with the logarithm of glucose concentration to obtain the linear equation:

[0058] I=2889.1+414.7lgcGlu(R 2 =0.982)#(1)

[0059] The detection limit (S / N=3) was 3.4×10 -7 mol / L, while the normal fasting glucose concentration is 3.92-6.16mmol / L, and the normal postprandial glucose concentration is 5.1-7.0mmol / L. Obviously, the glucose ECL sensing platform can meet this detection requirement well.

[0060] Figure 7 For CPNs PFBT-COOH / GCE was continuously scanned in glucose solution for 14 cycles and the ECL curve was continuously scanned for 250 s, which remained stable, indicating that the CPNs PFBT -COOH / GCE ECL sensing platform has good stability.

[0061] The present invention finds through the above examples that glucose can enhance CPNs PFBT -ECL signal of COOH / GCE platform and its ECL enhancement mechanism, such as Figure 8 As shown, CPNs PFBT After -COOH was modified on the GCE surface, CPNs PFBT -COOH will produce a stable ECL signal in the presence of K2S2O8, and the reaction formula involved is as follows:

[0062] CPNs PFBT -COOH+e - →CPNs PFBT -COOH ·- #(2)

[0063] S2O8 2- +e - →SO4 2- +SO4 ·- #(3)

[0064] CPNs PFBT -COOH ·- +SO4 ·- →CPNs PFBT -COOH * +SO4 2- #(4)

[0065] CPNs PFBT -COOH * →CPNs PFBT -COOH+hv#(5)

[0066] When glucose is added to the solution as a reactant, the CPNs modified on the electrode surface PFBT -COOH has a dual role similar to GOD and catalase (HRP), catalyzing the decomposition of glucose to produce H2O2, which is then converted into H2O2 by CPNs that mimic the action of HRP enzyme. PFBT -COOH catalyzes the in-situ production of a large amount of O2, which can serve as a co-reactant to catalyze the production of ECL.

[0067]

[0068]

[0069] This process is repeated over and over again, greatly enhancing the ECL signal and greatly improving the reaction sensitivity.

[0070] 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 method for preparing an electrochemiluminescent sensing platform for glucose detection, characterized in that: Carboxyl-functionalized CPNs were obtained by coprecipitation reaction of PFBT and PSMA. PFBT -COOH, using CPNs PFBT -COOH is used to modify the electrode surface; The specific steps are as follows: The PFBT solution and the PSMA solution are prepared respectively by using an organic solvent, the PFBT solution and the PSMA solution are mixed, the mixed solution is placed in pure water under ultrasonic conditions, nitrogen or an inert gas is slowly introduced below the liquid surface of the reaction system, the organic solvent in the reaction system is blown out by using nitrogen or an inert gas, and the mixture is obtained after filtering; The mass ratio of PFBT to PSMA is 1:0.15~0.25; the volume ratio of the mixed solution to pure water is 1.5~2.5:10; the mixed solution is placed in pure water for ultrasonic treatment for 10~20 min and then the organic solvent is blown out; and the solution is filtered using a 0.22 μm filter head.

2. The method for preparing the electrochemiluminescent sensing platform for glucose detection according to claim 1, characterized in that: The organic solvent is tetrahydrofuran.

3. An electrochemiluminescent sensor for glucose detection, characterized in that: It comprises an electrochemiluminescent sensing platform for glucose detection and potassium persulfate, wherein the electrochemiluminescent sensing platform for glucose detection is obtained by the preparation method according to any one of claims 1 to 2.

4. A method for preparing an electrochemiluminescent sensor for glucose detection, characterized in that: The invention comprises a method for preparing an electrochemiluminescent sensing platform for glucose detection according to any one of claims 1 to 2, wherein the obtained electrochemiluminescent sensing platform for glucose detection is used as a working electrode, and potassium persulfate is added to the working solution.

5. Use of the electrochemiluminescence sensor according to claim 3 in detecting glucose.

6. A glucose detection kit, characterized in that: The invention comprises an electrochemiluminescent sensing platform for glucose detection, potassium persulfate and a buffer solution, wherein the electrochemiluminescent sensing platform for glucose detection is obtained by the preparation method according to any one of claims 1 to 2.

7. The glucose detection kit according to claim 6, characterized in that: The buffer solution is a phosphate buffer.

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