Organic phototransistor fluorescent dual-mode glucose sensor and preparation method and application thereof

Abstract

The application provides an organic photoelectric transistor fluorescent dual-mode glucose sensor and a preparation method and application thereof, and the sensor is prepared by the following steps: dispersing inorganic nano powder in a conductive polymer solution to obtain a first mixed solution; immersing a first flexible fiber base material in the first mixed solution to obtain a first conductive fiber; mixing an inorganic quantum dot solution, a rare earth metal salt and an organic ligand to obtain a second mixed solution; placing a second flexible fiber base material in the second mixed solution and performing a hydrothermal reaction to obtain a second conductive fiber; coating conductive silver paste on two ends of the first conductive fiber to serve as a source electrode and a drain electrode; taking the second conductive fiber as a gate electrode; assembling the source electrode, the drain electrode and the gate electrode with a gel electrolyte to obtain an organic photoelectric transistor; and modifying glucose oxidase on a surface of the gate electrode of the organic photoelectric transistor to obtain the organic photoelectric transistor fluorescent dual-mode glucose sensor. The application has fast fluorescence and electrochemical response to glucose, high sensitivity and a good application prospect.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, specifically to an organic phototransistor fluorescent dual-mode glucose sensor, its preparation method, and its applications. Background Technology

[0002] As a key substance in human energy metabolism, the accurate monitoring of glucose concentration is of great significance in disease diagnosis, health management, and biological process analysis. Traditional glucose detection methods, such as enzyme electrode methods and spectroscopic analysis, have been widely used in clinical and laboratory settings. However, with the development of wearable devices, real-time health monitoring, and personalized medicine, higher requirements are placed on glucose sensors, including flexibility, multi-mode signal output, high sensitivity, and good environmental adaptability.

[0003] In recent years, metal-organic frameworks (MOFs) have attracted widespread attention in the field of sensing due to their high porosity, tunable pore structure, and good chemical stability. Lanthanide MOFs (Ln-MOFs), in particular, are widely used in fluorescence sensing due to their wide bandwidth, long fluorescence lifetime, and unique photosensitive optical properties of associated ligands. Meanwhile, phototransistors, as functional devices that convert light signals into electrical signals, exhibit advantages such as high gain, low noise, and ease of integration in biosensing, showing great promise, especially in flexible electronics and wearable sensing systems.

[0004] Current glucose detection methods have the following limitations: First, most sensors rely on a single electrochemical or fluorescence signal, making them susceptible to interference from the detection environment, operational differences, and sample matrix, leading to false positives or signal drift and affecting detection reliability. Second, existing sensors are mostly based on rigid substrates (such as silicon wafers, glass, and rigid polymers), making it difficult to adapt to the curved surfaces or dynamic deformations of the human body, thus limiting their application in wearable devices. Third, some sensors have complex manufacturing processes and use toxic or poorly biocompatible materials, which is not conducive to practical application. Fourth, sensitivity and detection range are often difficult to balance, and the detection capability at low concentrations is insufficient. Summary of the Invention

[0005] In view of the technical problems existing in the background art, this application provides an organic phototransistor fluorescent dual-mode glucose sensor, its preparation method and application, aiming to solve the technical problems of inaccurate detection results of existing sensors with single signal output for detected substances and the inability to achieve wearable technology.

[0006] In a first aspect, this application provides a method for preparing an organic phototransistor fluorescent dual-mode glucose sensor, comprising the following steps: S1. Disperse inorganic nanopowder in a conductive polymer solution to obtain a first mixed solution; immerse a first flexible fiber substrate in the first mixed solution to obtain a first conductive fiber; S2. An inorganic quantum dot solution is mixed with a rare earth metal salt and an organic ligand to obtain a second mixed solution; a second flexible fiber substrate is placed in the second mixed solution and subjected to a hydrothermal reaction to obtain a second conductive fiber; S3. Coat both ends of the first conductive fiber with conductive silver paste to serve as the source and drain; use the second conductive fiber as the gate; assemble the source, drain, and gate with a gel electrolyte to obtain an organic phototransistor; S4. Glucose oxidase is modified on the gate surface of the organic phototransistor to obtain an organic phototransistor fluorescent dual-mode glucose sensor.

[0007] As a further improvement of this application, in step S1, the first flexible fiber substrate is selected from one or more of aramid fiber, nylon fiber, polyester fiber, cotton fiber, polyamide fiber, and silk fiber; the inorganic nanopowder is ZrS3 with a particle size of 5~15nm.

[0008] As a further improvement of this application, in step S1, the concentration of the conductive polymer in the first mixed solution is 1.0~1.3wt%, and the concentration of the inorganic nanopowder is 0.002~0.04wt%.

[0009] As a further improvement to this application, the conductive polymer is selected from one of PEDOT:PSS, polyaniline, and polyacetylene.

[0010] As a further improvement of this application, in step S2, the concentration of the inorganic quantum dot solution is 0.9~3.6wt%; the inorganic quantum dots in the inorganic quantum dot solution are WS2 quantum dots or ZnO quantum dots.

[0011] As a further improvement of this application, in step S2, the second flexible fiber substrate is selected from one or more of metal fibers, carbon black fibers, conductive metal compound fibers, and conductive polymer fibers.

[0012] As a further improvement of this application, in step S2, the rare earth metal salt is terbium nitrate hexahydrate or europium nitrate hexahydrate; The organic ligand is 3,3',4,4'-biphenyltetracarboxylic dianhydride or 3,5-dicarboxyphenylboronic acid; The concentration of rare earth metal salts in the second mixed solution is 0.03~0.06 mol / L, and the concentration of organic ligands is 0.01~0.02 mol / L.

[0013] As a further improvement of this application, in step S2, the temperature of the hydrothermal reaction is 120~180℃ and the reaction time is 12~48h.

[0014] Secondly, this application provides an organic phototransistor fluorescent dual-mode glucose sensor, which is prepared by the method described in the first aspect.

[0015] Thirdly, this application provides an application of the organic phototransistor fluorescence dual-mode glucose sensor as described in the second aspect in glucose detection.

[0016] The beneficial effects of this application are as follows: This application provides an organic phototransistor fluorescent dual-mode glucose sensor, its preparation method, and its application. The method involves dispersing inorganic nanoparticles in a conductive polymer solution to obtain a first mixed solution; immersing a first flexible fiber substrate in the first mixed solution to obtain a first conductive fiber; mixing an inorganic quantum dot solution with a rare earth metal salt and an organic ligand to obtain a second mixed solution; placing the second flexible fiber substrate in the second mixed solution and subjecting it to a hydrothermal reaction to obtain a second conductive fiber; coating both ends of the first conductive fiber with conductive silver paste to serve as the source and drain electrodes; using the second conductive fiber as the gate electrode; assembling the source, drain, and gate electrode with a gel electrolyte to obtain an organic phototransistor; and modifying the gate surface of the organic phototransistor with glucose oxidase to obtain the organic phototransistor fluorescent dual-mode glucose sensor. The organic phototransistor fluorescence dual-mode glucose sensor provided in this application utilizes the synergistic effect of inorganic quantum dots and Ln-MOF, as well as the composite of conductive polymers and inorganic nanomaterials, to achieve photoelectrochemical and fluorescence dual-mode sensing. The dual-channel signal output effectively avoids interference from a single signal mode, significantly improving the accuracy and reliability of the detection results. Simultaneously, the sensor has a simple fabrication process, low toxicity, and good repeatability. It exhibits fast fluorescence and electrochemical responses to glucose, high sensitivity, and a low detection limit. Furthermore, due to the use of flexible fibers as the substrate, the device possesses excellent flexibility and wearability, showing promising application prospects in smart wearables, smart anti-counterfeiting, and environmental monitoring.

[0017] This application uses fibers composed of composite conductive polymers and inorganic nanoparticles as the source and drain electrodes of a flexible electrochemical transistor, and inorganic quantum dot / Ln-MOF fibers as the gate electrode modified with glucose oxidase solution. The synergistic effect between the conductive polymer and inorganic nanoparticles is utilized to increase the channel electron transport efficiency, thereby improving the device's biosensing effect. Simultaneously, inorganic quantum dots are used to enhance the device's photoelectric effect and sensing performance, while Ln-MOF is used to improve the device's fluorescence detection performance. Dual-channel signal output improves the accuracy of the detection structure, ultimately resulting in a high-performance organic phototransistor fluorescence dual-mode glucose sensor based on inorganic quantum dots / Ln-MOF.

[0018] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0020] Figure 1 This is a scanning electron microscope image of the pretreated cotton fiber substrate in Example 1 of this application; Figure 2 This is a scanning electron microscope image of the pretreated carbon fiber substrate in Example 1 of this application; Figure 3 This is a scanning electron microscope image of the conductive polymer fiber in Example 1 of this application; Figure 4 This is a scanning electron microscope image of the WS2 / Tb-MOF fibers prepared in Example 1 of this application; Figure 5 This is a photograph of the WS2 / Tb-MOF fiber prepared in Example 1 of this application. Figure 6 This is a graph showing the output characteristics of the organic phototransistor prepared in Example 1 of this application; Figure 7 This is a graph showing the transfer characteristics of the organic phototransistor prepared in Example 1 of this application; Figure 8 This is a switching characteristic curve of the organic phototransistor prepared in Example 1 of this application; Figure 9 This is a graph showing the electrochemical sensing characteristics of the organic phototransistor fluorescent dual-mode glucose sensor prepared in Example 1 of this application. Figure 10 The fluorescence sensing characteristic curve of the organic phototransistor fluorescence dual-mode glucose sensor prepared in Example 1 of this application is shown. Figure 11 This is a graph showing the electrochemical sensing characteristics of the organic phototransistor fluorescent dual-mode glucose sensor prepared using aramid fibers in Example 8 of this application. Detailed Implementation

[0021] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0023] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0024] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0026] Existing glucose sensors mostly rely on a single signal output, which is easily affected by environmental factors and other factors, thus affecting their accuracy. In addition, most of them are based on rigid substrates, which limits their application in the wearable field.

[0027] To address the technical problems of inaccurate detection results and the inability to achieve wearable applications caused by existing sensors relying on a single signal output, this application provides an organic phototransistor fluorescent dual-mode glucose sensor, its preparation method, and its application. By utilizing the synergistic effect of inorganic quantum dots and Ln-MOF, as well as the composite of conductive polymers and inorganic nanomaterials, the technical effects of improving detection accuracy, achieving dual-mode photofluorescence response, enhancing device sensitivity, and enabling wearable applications can be achieved.

[0028] In a first aspect, embodiments of this application provide a method for preparing an organic phototransistor fluorescent dual-mode glucose sensor, comprising the following steps: S1. Disperse inorganic nanopowder in a conductive polymer solution to obtain a first mixed solution; immerse a first flexible fiber substrate in the first mixed solution to obtain a first conductive fiber; S2. The inorganic quantum dot solution is mixed with rare earth metal salts and organic ligands to obtain a second mixed solution; the second flexible fiber substrate is placed in the second mixed solution and subjected to a hydrothermal reaction to obtain a second conductive fiber; S3. Coat both ends of the first conductive fiber with conductive silver paste to serve as the source and drain; use the second conductive fiber as the gate; assemble the source, drain, and gate with the gel electrolyte to obtain an organic phototransistor; S4. Glucose oxidase was modified on the gate surface of an organic phototransistor to obtain an organic phototransistor fluorescent dual-mode glucose sensor.

[0029] This application prepares the active layer of an organic phototransistor by liquid-phase immersion in a first flexible fiber substrate, which helps improve the dispersion of conductive polymer materials and enhances the amplification and transfer functions of the transistor. Inorganic quantum dots / Ln-MOFs are hydrothermally grown on a second flexible fiber substrate using a solvothermal method. The photosensitive properties of quantum dots are used to enhance the photoelectric effect, and the fluorescence properties of Ln-MOFs are used to achieve fluorescence detection. Combined with the specific recognition of glucose by glucose oxidase, a sensor with photochemical and fluorescence dual-response channels is constructed on the flexible fiber substrate, effectively solving the problems of single signal output being susceptible to interference and poor wearability.

[0030] Furthermore, in some embodiments, in step S1, the first flexible fiber substrate is selected from one or more of aramid fiber, nylon fiber, polyester fiber, cotton fiber, polyamide fiber, and silk fiber; the inorganic nanopowder is ZrS3 with a particle size of 5~15nm.

[0031] In the technical solution of this application embodiment, hydrophilic fibers such as cotton fibers are selected as the first flexible substrate. Utilizing the abundant polar groups (such as hydroxyl groups) on their surface, a mixed solution containing conductive polymers such as PEDOT:PSS and ZrS3 nanoparticles is uniformly adsorbed and stably loaded through wetting. The incorporation of ZrS3 with a particle size of 5-15 nm serves two purposes: firstly, its nanoscale structure can be effectively dispersed in the polymer matrix, preventing aggregation; secondly, ZrS3 and the conductive polymer PEDOT:PSS can form a heterojunction structure, promoting interfacial charge separation and transport under an electric field, synergistically improving the conductivity and carrier mobility of the channel layer, thereby enhancing the current response and sensing sensitivity of subsequent transistor devices. Specifically, the first flexible fiber substrate is preferably cotton fiber, as the hydrophilicity of cotton allows for better composite bonding of the conductive polymer to the surface. The first flexible fiber substrate is immersed in the first mixed solution 1-5 times, with each immersion lasting 10-20 minutes.

[0032] Furthermore, in some embodiments, in step S1, the concentration of the conductive polymer in the first mixed solution is 1.0~1.3wt%, and the concentration of the inorganic nanopowder is 0.002~0.04wt%. The conductive polymer is selected from PEDOT:PSS, polyaniline, and polyacetylene.

[0033] In the technical solution of this application embodiment, the conductive polymer within a suitable concentration range can form a continuous and stable conductive network, ensuring that the fiber substrate has good basic conductivity and film-forming properties. Simultaneously, the appropriately added nanoparticles can be uniformly dispersed in the polymer matrix, avoiding conductive pathway blockage or interface defects caused by excessive agglomeration. Under suitable ratios, the two can form an effective heterojunction interface, promoting charge separation and transport, and synergistically improving the carrier mobility and photoelectric response capability of the composite fiber. Specifically, the ratio of the conductive polymer solution to the inorganic nanoparticles is (5~20mL):(0.5~2mg). The conductive polymer is preferably PEDOT:PSS, which has high conductivity and high compatibility with fibers, making it easy to combine with the fiber substrate and promoting the composite of inorganic nanoparticles on the surface of the fiber substrate.

[0034] Furthermore, in some embodiments, in step S2, the concentration of the inorganic quantum dot solution is 0.9~3.6wt%; the inorganic quantum dots in the inorganic quantum dot solution are WS2 quantum dots or ZnO quantum dots.

[0035] In the technical solution of this application embodiment, the appropriate concentration of the inorganic quantum dot solution ensures its uniform dispersion and effective loading in the Ln-MOF structure in the subsequent hydrothermal system, avoiding aggregation and uneven deposition due to excessive concentration, or insufficient formation of photoactive sites due to insufficient concentration. WS2 quantum dots have a narrow band gap and strong visible light absorption, which can effectively improve the light capture and photoelectric conversion efficiency of the gate; ZnO quantum dots have good electron transport characteristics and chemical stability. Both can form a synergistic interface with Ln-MOF, promoting the separation and transfer of electron-hole pairs under photoexcitation, thereby enhancing the photoresponse performance of the device and providing a material basis for fluorescence signal modulation, ultimately achieving highly sensitive dual-mode glucose detection. Specifically, the inorganic quantum dot solution, rare earth metal salt, and organic ligand can be ultrasonically treated at room temperature for 10-30 minutes to mix uniformly and form a metal-organic framework. The inorganic quantum dots are preferably WS2 quantum dots, which have a good light absorption effect, can improve photoelectric conversion efficiency, and enhance device sensitivity.

[0036] Furthermore, in some embodiments, in step S2, the second flexible fiber substrate is selected from one or more of metal fibers, carbon black fibers, conductive metal compound fibers, and conductive polymer fibers.

[0037] In the technical solution of this application embodiment, the conductive substrate not only possesses excellent conductivity, which is beneficial for the effective application of the gate electric field and the rapid collection and transport of charge, enhancing the overall electrical response performance of the device; at the same time, its surface characteristics are also conducive to the adsorption, nucleation, and directional growth of rare earth metal ions and organic ligands during hydrothermal processes, and to the formation of a uniform and robust load structure with inorganic quantum dots, thereby synergistically improving the photoelectric conversion efficiency and fluorescence signal stability of the gate, laying a structural foundation for constructing a high-performance, integrable flexible glucose dual-mode sensing interface. Specifically, the second flexible fiber substrate is preferably carbon fiber, which allows the deposition of a Tb-MOF structured luminescent metal-organic framework on its surface. Due to the good conductivity of the conductive fiber, the device can perform electrochemical sensing tests on glucose. Before the experiment, the first and second flexible fiber substrates need to be ultrasonically cleaned in water and ethanol solutions for 10-20 minutes, then rinsed with deionized water and dried to obtain a clean fiber substrate, preparing for subsequent immersion in conductive polymer solution and deposition of metal framework particles. The average diameter of the first and second flexible fiber substrates is 3-7 μm.

[0038] Further, in some embodiments, in step S2, the rare earth metal salt is terbium nitrate hexahydrate or europium nitrate hexahydrate; the organic ligand is 3,3',4,4'-biphenyltetracarboxylic dianhydride or 3,5-dicarboxyphenylboronic acid; the concentration of the rare earth metal salt in the second mixed solution is 0.03~0.06 mol / L, and the concentration of the organic ligand is 0.01~0.02 mol / L.

[0039] In the technical solution of this application embodiment, terbium nitrate hexahydrate or europium nitrate hexahydrate is selected as a rare earth metal salt because its ions exhibit characteristic, high-purity fluorescence emission in the coordination environment, providing an ideal signal output unit for specific fluorescence sensing. Meanwhile, multidentate organic ligands such as 3,3',4,4'-biphenyltetracarboxylic dianhydride or 3,5-dicarboxyphenylboronic acid, with their abundant oxygen-containing functional groups (carboxyl, anhydride, or borate groups), can efficiently coordinate with rare earth ions to construct a structurally stable, tunable lanthanide metal-organic framework (Ln-MOF). Controlling the concentrations of rare earth metal salts and organic ligands within an appropriate range helps ensure sufficient contact and coordination equilibrium of the reactants, promoting the in-situ growth of a well-crystallized, uniformly loaded Ln-MOF layer on the conductive fiber surface. This forms a sensitive interface with high fluorescence quantum efficiency and a stable framework, providing a reliable platform for glucose oxidase immobilization and subsequent fluorescence sensing. The molar ratio of rare earth metal salts to organic ligands is (3~6):(1~2).

[0040] Furthermore, in some embodiments, in step S2, the hydrothermal reaction temperature is 120~180℃ and the reaction time is 12~48h.

[0041] In the technical solution of this application embodiment, a suitable hydrothermal reaction temperature can provide sufficient reaction activation energy to promote the formation of coordination bonds and crystal growth, while avoiding excessive temperature leading to ligand decomposition or fiber substrate damage; a suitable reaction time is beneficial for the uniform dispersion and fixation of inorganic quantum dots in the growing MOF structure, achieving close composite of the two.

[0042] Secondly, embodiments of this application provide an organic phototransistor fluorescent dual-mode glucose sensor, which is prepared by the above-described method.

[0043] The sensor's structure comprises: conductive polymer fibers coated with conductive silver paste at both ends serving as the source and drain electrodes; and inorganic quantum dot / Ln-MOF fibers modified with glucose oxidase solution serving as the gate electrode. The source / drain electrodes and the gate electrode are arranged in parallel with a 1-2 mm gap, with a gel electrolyte placed at the gap as an insulating layer. The gel electrolyte completely encapsulates the source / drain electrodes and the gate electrode fibers. The conductive polymer fibers form the channel between the source and drain electrodes. The synergistic effect of inorganic quantum dots and Ln-MOF is utilized to improve the composite performance of the material and the biosensing effect of the device. Inorganic quantum dots enhance the photoelectric effect and sensing performance of the device, while Ln-MOF improves the fluorescence detection performance. Dual-channel signal output improves the accuracy of the detection structure, ultimately resulting in a high-performance organic phototransistor fluorescence dual-mode glucose sensor based on inorganic quantum dots / Ln-MOF.

[0044] Thirdly, embodiments of this application provide an application of an organic phototransistor fluorescence dual-mode glucose sensor in glucose detection.

[0045] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0046] Example 1 This embodiment provides a method for preparing an organic phototransistor fluorescence dual-mode glucose sensor, including the following steps: S1. Cotton fibers and carbon fibers were ultrasonically cleaned in deionized water and ethanol, respectively, for 15 minutes each. They were then dried and stored for later use. Scanning electron microscopy images are shown below. Figures 1 to 2 As shown in the figure, the fiber surface has a smooth structure after cleaning; 0.01 mol ZrOCl2·8H2O was dissolved in 70 mL of n-hexane, and then 0.05 mol thiourea was added. After stirring the solution for 3 hours, it was transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave and then placed in an oven at 200°C for 72 hours. After the reaction was completed, a reddish-brown precipitate was obtained. The product was filtered and washed three times with carbon sulfide, acetone and deionized water, respectively. After washing, it was dried in an oven at 60°C for 8 hours. After drying, it was ground into a fine powder with a mortar and pestle and calcined at 500°C for 3 hours to obtain white nano ZrS3 powder. Take 10 mL of 1.3 wt% PEDOT:PSS and add it to a 25 mL beaker. Then add 0.1 mL of dimethyl sulfoxide (DMSO) and 0.5 mL of ethylene glycol. Sonicate the mixture to disperse it evenly to obtain a PEDOT:PSS solution. 1 mg of nano-ZrS3 powder was dispersed in 10 ml of PEDOT:PSS solution to obtain a first mixed solution. The pretreated cotton fiber substrate was immersed in the first mixed solution, and this immersion was repeated twice to obtain conductive polymer fibers adsorbed with two layers of conductive polymer. The scanning electron microscope image is shown below. Figure 3 As shown, after soaking in a mixed solution of PEDOT:PSS and ZrS3, the surface of the cotton fibers is coated with a uniformly dispersed conductive polymer, and the gaps between the fibers are also covered by the conductive polymer. Furthermore, it can be seen that spherical ZrS3 particles are piled up on the fiber surface. S2. Dissolve 2g of WS2 powder in 50mL of N,N-dimethylformamide solvent. Stir the solution for 10min and then sonicate it in an ultrasonic machine for 1h. Then transfer the liquid to a 100mL round-bottom flask and heat it in an oil bath at 140℃ for 16h with stirring. After the solution cools to room temperature, centrifuge the upper liquid at 8000rpm for 15min to obtain the WS2 quantum dot solution. Take 20 mL of the prepared WS2 quantum dot solution, add 0.6 mmol of terbium nitrate hexahydrate and 0.2 mmol of 3,3',4,4'-biphenyltetracarboxylic dianhydride, and stir to mix. Sonicate for 30 min to obtain a second mixed solution. Place the pretreated carbon fiber substrate in the second mixed solution and perform a hydrothermal reaction at 150℃ for 12 h to obtain WS2 / Tb-MOF fibers. Its scanning electron microscope image is shown below. Figure 4 As shown in the image, after the hydrothermal reaction, a thick layer of WS2 / Tb-MOF particles with a diameter of 500-800 nm was densely grown on the surface of the carbon fiber; its actual image is shown below. Figure 5 As shown, the fiber appears white under natural light and emits green fluorescence under 254nm excitation light, which is the fluorescence characteristic of Tb-MOF. S3. Take a conductive polymer fiber and coat both ends with conductive silver paste to serve as the source and drain. Take a WS2 / Tb-MOF fiber as the gate, both about 1 cm in length. Place them parallel to each other on a PET plastic plate with a 1 mm spacing. Then drop in an ion gel electrolyte to coat the two fibers to obtain an organic phototransistor. Figure 6 The figure shows the output characteristic curves of the organic phototransistor. As can be seen from the figure, the device exhibits a typical depletion mode. That is, when the gate voltage is constant, the output current gradually increases with the increase of the source-drain voltage, and the curve shows a good linear trend. When the source-drain voltage is constant, the output current gradually decreases with the increase of the gate voltage, indicating that the fabricated organic phototransistor has a good working state. Figure 7 The graph shows the transfer characteristic curves of an organic phototransistor. It can be seen that when the source-drain voltage is constant, the source-drain current gradually decreases as the gate voltage increases, which is consistent with the working principle of a transistor. Figure 6 The output curve is consistent; Figure 8 The graph shows the switching characteristics of an organic phototransistor. As can be seen from the graph, under a constant source-drain voltage, the current changes regularly with the voltage switching on and off, and the cycle stability is good, indicating that the device has good operational stability. S4. Take 20 mg of glucose oxidase powder, dissolve it in 1 mL of phosphate buffer solution (PBS) with a pH of 7.2, mix it evenly by sonication to obtain a 20 mg / mL glucose oxidase solution, and store it in a refrigerator at 4°C. Glucose oxidase was drop-coated onto the gate surface of an organic phototransistor to obtain a fluorescent dual-mode glucose sensor.

[0047] Prepare glucose solutions of different concentrations: Weigh 0.09 g of β-D-glucose powder and dissolve it in 50 mL of PBS solution with pH=7.2 to obtain a 10 mM glucose solution. Then, dilute the 10 mM glucose solution with PBS solution with pH=7.2 at a certain ratio to obtain glucose solutions with concentrations of 1 mM, 100 µM, 10 µM, 1 µM, 100 nM, 10 nM, and 1 nM, respectively. Use the organic phototransistor fluorescence dual-mode glucose sensor prepared in Example 1 to detect the above glucose solutions of different concentrations. Figure 9 The figure shows the electrochemical sensing characteristic curves. As can be seen from the figure, the organic phototransistor fluorescence dual-mode glucose sensor prepared in this application has a step-type current response to different concentrations of glucose, indicating that the sensor can sensitively detect glucose. Figure 10The graph shows the fluorescence sensing characteristics. As can be seen from the graph, the fluorescence intensity gradually decreases with the increase of glucose concentration, showing a regular change. This indicates that the prepared glucose sensor has a regular decreasing response to glucose solutions of different concentrations and can sensitively detect glucose.

[0048] Comparative Example 1 Comparative Example 1 provides a method for preparing an organic phototransistor fluorescent dual-mode glucose sensor. The only difference from Example 1 is that nano ZrS3 powder was not added in step S1. Other experimental parameters and conditions are basically the same as in Example 1, and will not be repeated here.

[0049] Comparative Example 2 Comparative Example 2 provides a method for preparing an organic phototransistor fluorescent dual-mode glucose sensor. The only difference from Example 1 is that WS2 quantum dots are not added in step S2. Other experimental parameters and conditions are basically the same as in Example 1, and will not be repeated here.

[0050] The organic phototransistor fluorescent dual-mode glucose sensors obtained in Example 1 and Comparative Examples 1-2 were tested for their electrical performance, and the results are shown in the table below.

[0051] Table 1 Performance test results of Example 1 and Comparative Examples 1-2 Comparing Example 1 and Comparative Example 1, it can be seen that the current of the organic phototransistor prepared in Comparative Example 1 is smaller than that of the transistor in Example 1. The reason is that the addition of nano-zirconium sulfide can form a heterojunction with PEDOT:PSS, which generates more electron-hole pairs when voltage is applied, thus improving electron mobility. However, when cotton fibers soaked in PEDOT:PSS solution are used as the source and drain electrodes of the transistor, without the addition of nano-zirconium sulfide, there is no composite effect of conductive polymer and inorganic nanoparticles, hence the current is reduced.

[0052] Comparing Example 1 and Comparative Example 2, it can be seen that the photocurrent of the organic phototransistor prepared in Comparative Example 2 is smaller than that of the transistor in Example 1. The reason is that MOF alone is not a photosensitive material and does not have photoelectric conversion function, while WS2 is a photosensitive material that responds to light. Since there is no addition of WS2, only the fiber with MOF grown on it is used as the gate, which leads to a weakening of the photoelectric effect of the transistor and a decrease in photocurrent.

[0053] Examples 2-3 and Comparative Examples 3-4 Examples 2-3 and Comparative Examples 3-4 respectively provide a method for preparing an organic phototransistor fluorescent dual-mode glucose sensor. Compared with Example 1, the only difference is that in step S1, the concentrations of the conductive polymer and inorganic nanopowder in the first mixed solution are different, as shown in Table 2. Other experimental parameters and conditions are basically the same as in Example 1, and will not be repeated here.

[0054] Table 2 Comparison of parameters in Examples 1-3 and Comparative Examples 3-4 The obtained organic phototransistor fluorescence dual-mode glucose sensor was tested for its electrical performance, and the results are shown in Table 3.

[0055] Table 3 Performance test results of Examples 1-5 and Comparative Examples 3-6 Comparing Examples 1-5 and Comparative Examples 3-6, it can be seen that when the content of nano-zirconium sulfide and the amount of PEDOT:PSS solution are controlled within a certain range, the current and transconductance of the fiber-based transistor are both large, and the current regulation effect is good. However, when the content of nano-zirconium sulfide is too high, the overall conductivity of the polymer fiber decreases due to the non-conductive nature of zirconium sulfide, resulting in a decrease in current. When the content of nano-zirconium sulfide is too low, its degree of composite with the conductive polymer PEDOT:PSS decreases, resulting in a decrease in electron transfer rate and a decrease in current.

[0056] Examples 6-7 and Comparative Examples 7-8 Examples 6-7 and Comparative Examples 7-8 respectively provide a method for preparing an organic phototransistor fluorescent dual-mode glucose sensor. Compared with Example 1, the only difference is that the concentration of the inorganic quantum dot solution is different in step S2, as shown in Table 4. Other experimental parameters and conditions are basically the same as those in Example 1, and will not be repeated here.

[0057] Table 4 Comparison of parameters in Examples 6-7 and Comparative Examples 7-8 The obtained organic phototransistor fluorescence dual-mode glucose sensor was tested for its electrical performance, and the results are shown in Table 5.

[0058] Table 5 Performance test results of Examples 1, 6-7 and Comparative Examples 7-8 Comparing Examples 1, 6-7 and Comparative Examples 7-8, it can be seen that when the concentration of the inorganic quantum dot solution is within a reasonable range, the photocurrent of the transistor does not change significantly. When the quantum dot concentration is too low or too high, the photocurrent of the transistor will decrease. This is because when the quantum dot concentration decreases, the absorption effect of the gate on light will be weakened accordingly. When the quantum dot concentration is too high, its adsorption on the gate surface will be uneven, resulting in a decrease in photocurrent.

[0059] Examples 8-12 Examples 8-12 provide methods for preparing organic phototransistor fluorescent dual-mode glucose sensors. Compared to Example 1, the only difference is that the cotton fiber substrate is replaced with aramid fiber, nylon fiber, polyester fiber, polyamide fiber, and silk fiber, respectively. Other experimental parameters and conditions are basically the same as in Example 1 and will not be repeated here. The obtained organic phototransistor fluorescent dual-mode glucose sensors still exhibit sensitive glucose detection performance. The detection results of Example 8 are as follows: Figure 11 As shown.

[0060] Examples 13-14 and Comparative Examples 9-10 Examples 13-14 and Comparative Examples 9-10 respectively provide a method for preparing an organic phototransistor fluorescent dual-mode glucose sensor. Compared with Example 1, the only difference is the molar amount of terbium nitrate hexahydrate and 3,3ˈ,4,4ˈ-biphenyltetracarboxylic dianhydride. Other experimental parameters and conditions are basically the same as in Example 1, and will not be repeated here. The performance of the obtained organic phototransistor fluorescent dual-mode glucose sensor was tested, and the results are shown in Table 6.

[0061] Table 6 Performance test results of Examples 13-14 and Comparative Examples 9-10 It can be seen that when the molar ratio of terbium nitrate hexahydrate to 3,3´,4,4´-biphenyltetracarboxylic dianhydride is (3~6):(1~2), the generated MOF particles have a suitable particle size and good deposition uniformity on the fiber substrate. Too much or too little terbium nitrate hexahydrate will cause the particle size of MOF particles to change, thereby affecting the deposition uniformity on the fiber substrate, and thus weakening the fluorescence sensing and electrosensing performance.

[0062] Examples 15-16 and Comparative Examples 11-12 Examples 15-16 and Comparative Examples 11-12 respectively provide a method for preparing an organic phototransistor fluorescent dual-mode glucose sensor. Compared with Example 1, the only difference is the temperature and time of the hydrothermal reaction. Other experimental parameters and conditions are basically the same as in Example 1, and will not be repeated here. The performance of the obtained organic phototransistor fluorescent dual-mode glucose sensor was tested, and the results are shown in Table 7.

[0063] Table 7 Performance test results of Examples 15-16 and Comparative Examples 11-12 It can be seen that excessively high hydrothermal reaction temperature and excessively long hydrothermal reaction time will result in excessively large MOF particle size and reduced adhesion of particles to the fiber substrate; while excessively low hydrothermal reaction temperature and excessively short hydrothermal reaction time will result in MOF particles not forming properly or fewer particles being synthesized, which will affect the fluorescence sensing and electrosensing effects and reduce sensor performance.

[0064] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for preparing an organic phototransistor fluorescence dual-mode glucose sensor, characterized in that, Includes the following steps: S1. Disperse inorganic nanopowder in a conductive polymer solution to obtain a first mixed solution; immerse a first flexible fiber substrate in the first mixed solution to obtain a first conductive fiber; S2. An inorganic quantum dot solution is mixed with a rare earth metal salt and an organic ligand to obtain a second mixed solution; a second flexible fiber substrate is placed in the second mixed solution and subjected to a hydrothermal reaction to obtain a second conductive fiber; S3. Coat both ends of the first conductive fiber with conductive silver paste to serve as the source and drain electrodes; The second conductive fiber is used as the gate electrode; the source electrode, drain electrode, and gate electrode are assembled with a gel electrolyte to obtain an organic phototransistor; S4. Glucose oxidase is modified on the gate surface of the organic phototransistor to obtain an organic phototransistor fluorescent dual-mode glucose sensor.

2. The method for preparing the organic phototransistor fluorescence dual-mode glucose sensor according to claim 1, characterized in that, In step S1, the first flexible fiber substrate is selected from one or more of aramid fiber, nylon fiber, polyester fiber, cotton fiber, polyamide fiber, and silk fiber; the inorganic nanopowder is ZrS3 with a particle size of 5~15nm.

3. The method for preparing the organic phototransistor fluorescent dual-mode glucose sensor according to claim 1, characterized in that, In step S1, the concentration of the conductive polymer in the first mixed solution is 1.0~1.3wt%, and the concentration of the inorganic nanopowder is 0.002~0.04wt%.

4. The method for preparing the organic phototransistor fluorescence dual-mode glucose sensor according to claim 3, characterized in that, The conductive polymer is selected from one of PEDOT:PSS, polyaniline, and polyacetylene.

5. The method for preparing the organic phototransistor fluorescence dual-mode glucose sensor according to claim 1, characterized in that, In step S2, the concentration of the inorganic quantum dot solution is 0.9~3.6wt%; the inorganic quantum dots in the inorganic quantum dot solution are WS2 quantum dots or ZnO quantum dots.

6. The method for preparing the organic phototransistor fluorescence dual-mode glucose sensor according to claim 1, characterized in that, In step S2, the second flexible fiber substrate is selected from one or more of metal fibers, carbon black fibers, conductive metal compound fibers, and conductive polymer fibers.

7. The method for preparing the organic phototransistor fluorescence dual-mode glucose sensor according to claim 1, characterized in that, In step S2, the rare earth metal salt is terbium nitrate hexahydrate or europium nitrate hexahydrate; The organic ligand is 3,3',4,4'-biphenyltetracarboxylic dianhydride or 3,5-dicarboxyphenylboronic acid; The concentration of rare earth metal salt in the second mixed solution is 0.03~0.06 mol / L, and the concentration of organic ligand is 0.01~0.02 mol / L.

8. The method for preparing the organic phototransistor fluorescent dual-mode glucose sensor according to claim 1, characterized in that, In step S2, the temperature of the hydrothermal reaction is 120~180℃, and the reaction time is 12~48h.

9. An organic phototransistor fluorescence dual-mode glucose sensor, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

10. The application of the organic phototransistor fluorescence dual-mode glucose sensor as described in claim 9 in glucose detection.

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