Flexible sensor for detecting rutin content, preparation method, and in vivo rutin detection method

Abstract

The present invention relates to the field of electrochemical detection technology, and provides a flexible sensor for detecting rutin content, a preparation method, and a method for detecting rutin in vivo. The flexible sensor includes a flexible substrate and a graphene electrode unit, and the graphene electrode unit is arranged on the flexible substrate; the graphene electrode unit includes a working electrode, a counter electrode, a reference electrode, and a guide rail, and the working electrode is provided with a first modification layer and a second modification layer from the inside to the outside, the first modification layer includes MOF-818 material, and the second modification layer includes HfSe2-COOH-SWCNT-Nafion material. The flexible sensor for detecting rutin content provided by the present invention has excellent conformability, can fit tightly to the surface of plant leaves, and can still maintain stable electrochemical performance under deformation. At the same time, it has faster detection speed, low production cost and simple process flow, and also has strong environmental adaptability, and can be used for detection in a variety of different environments, including field applications, combined with smart agriculture application scenarios.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical detection, and in particular to a flexible sensor for detecting rutin content, a preparation method thereof, and a living body rutin detection method. Background Art

[0002] Rutin is a flavonoid glycoside compound that is widely found in many plants such as buckwheat, sophora japonica, tea, and tomatoes.

[0003] Currently, rutin detection methods primarily include capillary electrophoresis, high-performance liquid chromatography, spectrophotometry, and electrochemical analysis. However, these methods are generally complex and time-consuming, relying on large-scale instrumentation and specialized technicians, resulting in high costs and difficulties in achieving convenient and rapid detection. Furthermore, these methods are typically performed in vitro in a laboratory setting, potentially causing significant damage to the plant during the sampling process, making them difficult to meet the requirements of real-time monitoring. In contrast, electrochemical methods, due to their simplicity, rapid response, high sensitivity, strong selectivity, and low cost, can meet the requirements of in situ plant detection. However, traditional rigid electrodes (such as glassy carbon, platinum, and gold electrodes) are unable to adapt to the soft and curved nature of plant surfaces, thus compromising detection accuracy and stability. Furthermore, in dynamic environments (such as wind-blown plant leaves), rigid electrodes often struggle to maintain stable contact and are prone to mechanical damage or pressure on the plant surface. Consequently, the application of traditional rigid electrode sensors in continuous plant monitoring is limited, making them unable to meet the requirements of plant physiological monitoring in vivo. Summary of the Invention

[0004] The present invention provides a flexible sensor for detecting rutin content, a preparation method and a method for detecting rutin in vivo, which are used to solve the defect that the application of existing rigid electrode sensors in continuous plant monitoring is limited and cannot meet the needs of plant physiological in vivo detection.

[0005] A first aspect of the present invention provides a flexible sensor for detecting rutin content, comprising: a flexible substrate and a graphene electrode unit, wherein the graphene electrode unit is provided on the flexible substrate.

[0006] The graphene electrode unit includes a working electrode, a counter electrode, a reference electrode and a guide rail. The working electrode is provided with a first modification layer and a second modification layer from the inside to the outside. The first modification layer includes MOF-818 material, and the second modification layer includes HfSe2-COOH-SWCNT-Nafion material.

[0007] According to the flexible sensor for detecting rutin content provided by the present invention, an Ag / AgCl ink layer is provided on the reference electrode to form an Ag / AgCl reference electrode.

[0008] According to the flexible sensor for detecting rutin content provided by the present invention, a copolyester insulation layer is provided in the area where the guide rail is located.

[0009] According to the flexible sensor for detecting rutin content provided by the present invention, the flexible substrate is a copolyester flexible substrate.

[0010] A second aspect of the present invention provides a method for preparing a flexible sensor according to any one of the above items, comprising the following steps.

[0011] The PI tape is patterned using a computer-controlled laser direct writer, and a graphene electrode unit body is obtained on the PI tape through induction.

[0012] The graphene electrode unit body on the PI tape is transferred to the flexible substrate.

[0013] A set amount of Ag / AgCl ink is coated on the exposed area of the reference electrode and heated and cured to obtain an Ag / AgCl reference electrode.

[0014] A copolyester insulation layer is prepared in the area where the guide rail is located.

[0015] The working electrode was modified to obtain a HfSe2-COOH-SWCNT-Nafion / MOF-818 / LIG / Ecoflex electrode.

[0016] According to the method for preparing a flexible sensor provided by the present invention, transferring the graphene electrode unit body on the PI tape to the flexible substrate specifically includes the following steps.

[0017] The Ecoflex mixed solution of a set ratio is applied to the graphene electrode unit body located on the PI tape by a spin coater, and then vacuum drying and heating treatment is performed.

[0018] The graphene electrode unit body is peeled off from the PI tape to obtain the graphene electrode unit located on the flexible substrate.

[0019] According to the flexible sensor preparation method provided by the present invention, the working electrode is modified to obtain a HfSe2-COOH-SWCNT-Nafion / MOF-818 / LIG / Ecoflex electrode, which specifically includes the following steps.

[0020] The working electrode was coated with a MOF-818 solution, and after the working electrode was dried, a HfSe2-COOH-SWCNT-Nafion solution was coated thereon. After the working electrode was dried, a HfSe2-COOH-SWCNT-Nafion / MOF-818 / LIG / Ecoflex electrode was obtained.

[0021] The method for preparing a flexible sensor provided by the present invention further includes the following steps.

[0022] A rutin-phosphate buffer solution with a set concentration is configured to perform IT detection on the flexible sensor, and a set of standard curves between the concentration of the rutin-phosphate buffer solution and the logarithm of the current are obtained according to the detection results.

[0023] The method for preparing a flexible sensor provided by the present invention further includes the following steps.

[0024] Prepare multiple rutin solutions of standard concentrations.

[0025] The flexible sensor is electrochemically calibrated using the rutin solution. If the slope deviation between the calculated working curve and the standard curve is within 15%, the flexible sensor is considered to be working properly.

[0026] A third aspect of the present invention provides a method for detecting rutin in vivo based on the flexible sensor as described in any one of the above items, comprising the following steps.

[0027] Punch holes at set locations on the surface of the plant leaves to be tested.

[0028] The flexible sensor is attached to the surface of the plant leaf to be tested, and the working electrode is aligned with the punched position.

[0029] Buffer solution was added dropwise to the punched position, and then the electrochemical workstation was connected to detect the concentration of rutin by chronoamperometry.

[0030] The flexible sensor for detecting rutin content provided by the present invention has better conformability than traditional rigid electrochemical sensors by integrating graphene electrode units on a flexible substrate. The flexible electrode can closely adhere to the surface of plant leaves and maintain stable electrochemical performance under deformation, while having high sensitivity and specificity. By providing a first modification layer (MOF-818 material) and a second modification layer (HfSe2-COOH-SWCNT-Nafion material) on the working electrode, the flexible sensor has faster detection speed, low production cost and simple process flow. It also has strong environmental adaptability and can be used for detection in a variety of different environments, including field applications, combined with smart agriculture application scenarios.

[0031] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 Schematic diagram of a flexible sensor for detecting rutin content provided by an embodiment of the present invention.

[0034] Figure 2 It is a schematic flow chart of a method for preparing a flexible sensor provided by an embodiment of the present invention.

[0035] Figure 3 1 is a diagram of the preparation process of the flexible sensor preparation method provided by an embodiment of the present invention.

[0036] Figure 4 Schematic diagram of modification of the working electrode in the flexible sensor preparation method provided by an embodiment of the present invention.

[0037] Figure 5 The figure is a flow chart of the in vivo rutin detection method provided by an embodiment of the present invention.

[0038] Figure 6 It is the IT curve of living body detection of the flexible sensor in the flexible sensor preparation method provided by the embodiment of the present invention.

[0039] Figure 7 The flexible sensor of the comparative example in the rutin living body detection method provided by the embodiment of the present invention is 1mM [Fe (CN) 6] 4− Cyclic voltammogram in solution.

[0040] Reference numerals:

[0041] 10. Flexible substrate; 20. Graphene electrode unit; 210. Working electrode; 220. Counter electrode; 230. Reference electrode; 30. Copolyester insulation layer. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0043] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0044] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on specific circumstances.

[0045] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," or "above" a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," or "below" a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0046] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0047] The following combination Figures 1 to 7 The present invention describes a flexible sensor for detecting rutin content, a preparation method, and a method for detecting rutin in vivo.

[0048] See also Figure 1 As shown, the flexible sensor for detecting rutin content provided by an embodiment of the present invention includes: a flexible substrate 10 and a graphene electrode unit 20 , and the graphene electrode unit 20 is provided on the flexible substrate 10 .

[0049] The graphene electrode unit 20 includes a working electrode 210, a counter electrode 220, a reference electrode 230 and a guide rail 240. The working electrode 210 is provided with a first modification layer and a second modification layer from the inside to the outside. The first modification layer includes MOF-818 material, and the second modification layer includes HfSe2-COOH-SWCNT-Nafion material.

[0050] The flexible sensor for detecting rutin content provided by the present invention integrates a graphene electrode unit 20 on a flexible substrate 10, and thus has better conformability than traditional rigid electrochemical sensors. The flexible electrode can closely adhere to the surface of plant leaves and maintain stable electrochemical performance even under deformation, while also having high sensitivity and specificity. By providing a first modification layer (MOF-818 material) and a second modification layer (HfSe2-COOH-SWCNT-Nafion material) on the working electrode 210, the flexible sensor has faster detection speed, low production cost and simple process flow. It also has strong environmental adaptability and can be used for detection in a variety of different environments, including field applications and combined with smart agriculture application scenarios.

[0051] Among them, the metal-organic framework structure of MOF-818 has an extremely high specific surface area and rich porosity, thereby providing more active sites to improve detection sensitivity. The HfSe2-COOH-SWCNT-Nafion composite material combines the high conductivity and catalytic activity of HfSe2, the high conductivity of COOH-SWCNT, and the ion exchange and anti-pollution capabilities of Nafion. The synergistic effect of multiple materials can enhance the surface activity of the working electrode 210, increase the detection surface area, improve the response signal and selectivity of the working electrode 210, and thus enhance the overall performance of the electrochemical flexible sensor. In addition, this composite structure not only enhances the sensitivity of the sensor, but also extends its service life and improves repeatability and stability.

[0052] Specifically, the flexible substrate 10 is a copolyester flexible substrate 10 (Ecoflex). Copolyester flexible substrate 10 exhibits excellent flexibility, deformability, and good adhesion, remaining stable when bent or stretched, making it suitable for close contact with plant surfaces. Furthermore, it possesses high mechanical strength and durability, capable of withstanding external forces without damage. It also possesses excellent chemical stability, resisting environmental influences such as acid and alkali corrosion and oxidation.

[0053] The graphene electrode unit 20 includes a working electrode 210 , a counter electrode 220 , a reference electrode 230 , and a guide rail 240 .

[0054] The working electrode 210 is the primary electrode for the electrochemical reaction. When voltage is applied, it can transfer electrons and undergo a redox reaction. Rutin, a flavonoid compound with antioxidant properties, can undergo a redox reaction (e.g., electron transfer) with the surface of the working electrode 210 during the electrochemical reaction, thereby generating a current signal. During the electrochemical detection process, rutin is typically oxidized or reduced on the surface of the working electrode 210. The current generated by this redox reaction is proportional to the logarithm of the rutin concentration. By measuring the change in current, the concentration of rutin can be quantitatively analyzed.

[0055] MOF-818 material specifically refers to MOF-818 (Metal-Organic Framework), and HfSe2-COOH-SWCNT-Nafion material specifically refers to a mixture of HfSe2 (hafnium diselenide), COOH-SWCNT (carboxylated multi-walled carbon nanotubes), and Nafion. These nanomaterials can catalyze the conversion of rutin to quercetin. When the flexible sensor is attached to the surface of a plant leaf, the real-time response signal of rutin can be recorded using chronoamperometry (IT), which can be used to determine the rutin content.

[0056] According to some embodiments of the present invention, an Ag / AgCl ink layer is disposed on the reference electrode 230 to form an Ag / AgCl reference electrode 230 .

[0057] By disposing an Ag / AgCl ink layer on the reference electrode 230 and forming the Ag / AgCl reference electrode 230 , a stable potential is provided and can be kept consistent for a long time, thereby ensuring the reliability and high repeatability of the electrochemical experiment results.

[0058] See also Figure 1 As shown, according to some embodiments of the present invention, a copolyester insulation layer 30 is provided in the area where the guide rail 240 is located.

[0059] By providing the copolyester insulating layer 30 in the area where the guide rail 240 is located, the guide rail area of the graphene electrode unit 20 can be insulated.

[0060] According to some embodiments of the present invention, conductive silver paste is applied, which mainly plays the role of conduction and adhesion in the connection between the electrode and the copper wire.

[0061] The following describes a method for preparing a flexible sensor provided by the present invention. The flexible sensor preparation method described below and the flexible sensor for detecting rutin content described above can be referenced to each other.

[0062] See also Figure 2 As shown, the method for preparing a flexible sensor provided by an embodiment of the present invention is used to prepare the flexible sensor described in the above embodiment, and includes the following steps.

[0063] S210, using a computer-controlled laser direct writer to pattern the PI (Polyimide) tape, and obtaining the main body of the graphene electrode unit 20 on the PI tape through induction.

[0064] S220 , transferring the main body of the graphene electrode unit 20 on the PI tape to the flexible substrate 10 .

[0065] S230 , coating a set amount of Ag / AgCl ink on the exposed area of the reference electrode 230 and heating and curing the ink to obtain the Ag / AgCl reference electrode 230 .

[0066] S240 , preparing a copolyester insulation layer 30 in the area where the guide rail 240 is located.

[0067] S250, modifying the working electrode 210 to obtain a HfSe2-COOH-SWCNT-Nafion / MOF-818 / LIG / Ecoflex electrode.

[0068] Specifically, in step S210, PI tape is attached to a polytetrafluoroethylene mold. The PI tape is then cleaned with distilled water and then ethanol. A computer-controlled laser writer then patterns the PI tape, producing a graphene electrode unit 20 (LIG electrode) with excellent conductivity.

[0069] It should be noted that the main body of the graphene electrode unit 20 at this time only includes the working electrode 210, the reference electrode 230, the counter electrode 220 and the guide rail 240, and does not include the packaging layer on the above-mentioned electrodes, and the material layers (first modification layer and second modification layer) modified on the working electrode 210.

[0070] In step S220, an Ecoflex mixture (composed of a main agent A and a curing agent B, mixed and stirred at a ratio of 10:1 for 5 to 10 minutes (preferably 10 minutes)) is spin-coated at a speed of 100 to 120 rpm (preferably 100 rpm) for 60 to 90 seconds (preferably 90 seconds) onto the PI tape with the main body of the graphene electrode unit 20. The mixture is then heated in a vacuum drying oven at 80 to 120°C (preferably 100°C) for 4 to 6 hours (preferably 4 hours). The main body of the graphene electrode unit 20 (LIG) is then peeled from the PI tape, yielding the graphene electrode unit 20 (LIG / Ecoflex electrode) on the flexible substrate 10.

[0071] That is, the graphene electrode unit 20 is prepared by laser printing a design pattern on a flexible PI tape and then transferring it to the copolyester Ecoflex.

[0072] In step S230 , a certain amount of Ag / AgCl ink is evenly applied to the exposed area of the reference electrode 230 , and then heated and cured at 80° C. to 120° C. (preferably 100° C.) for 30 min to 60 min (preferably 30 min) to obtain the Ag / AgCl reference electrode 230 .

[0073] In step S240 , a predetermined amount of Ecoflex is applied to the area where the guide rail 240 is located and then heated and cured to form a copolyester insulation layer, thereby insulating the area where the guide rail 240 is located. At this point, the LIG / Ecoflex three-electrode structure is complete.

[0074] Then, the electrode can be placed in a 0.01M to 0.1M (preferably 0.1M) dilute sulfuric acid solution and subjected to a cyclic voltammetry scan in the range of 0 to 1.5V to clean and activate the electrode surface.

[0075] In step S250, a MOF-818 solution and a COOH-SWCNT solution at concentrations of 0.5 to 2 mg / mL (preferably 1 mg / mL) are prepared in ultrapure water, and a HfSe2 solution at concentrations of 0.5 to 2 mg / mL (preferably 2 mg / mL) is prepared in anhydrous ethanol. The COOH-SWCNT and HfSe2 solutions are mixed, and a 0.05 to 0.1 wt% (preferably 0.1 wt%) Nafion solution is added. The mixed solution is then ultrasonically dispersed in ice water for 1 to 3 hours (preferably 2 hours) to obtain a uniformly dispersed HfSe2-COOH-SWCNT-Nafion mixed solution.

[0076] After the HfSe2-COOH-SWCNT-Nafion mixed solution is prepared, 4 μL to 8 μL (preferably 4 μL) of MOF-818 solution is first drop-coated on the working electrode 210. After drying, 4 μL to 8 μL (preferably 6 μL) of the HfSe2-COOH-SWCNT-Nafion mixed solution is drop-coated on the working electrode 210. After drying, the HfSe2-COOH-SWCNT-Nafion / MOF-818 / LIG / Ecoflex electrode is obtained.

[0077] According to some embodiments of the present invention, the method for preparing a flexible sensor further includes the following steps.

[0078] A rutin-phosphate buffer solution with a set concentration was configured to perform IT detection on the flexible sensor, and a set of relationship curves between the logarithm of the rutin-phosphate buffer solution concentration and the current were drawn based on the detection results.

[0079] Specifically, rutin-phosphate buffer solutions (pH = 7.4) with concentrations of 0, 1, 10, 50, 100, 300, 500, 700, and 1000 μM were prepared, respectively, and the flexible sensor prepared as above was used for IT detection (potential of 0.16 V to 0.18 V (preferably 0.18 V), sampling interval of 0.1 s, and detection time of 180 s to 300 s). As the concentration of the rutin solution increased, the current gradually increased, and a set of relationship curves between the logarithm of the concentration of the rutin-phosphate buffer solution and the current were obtained. Based on the relationship curves between the logarithm of the concentration of the rutin-phosphate buffer solution and the current, a standard curve of the flexible sensor was drawn. The linear equation was I = 0.477 lgC + 0.105 (μM), and the linear range could reach 1 μM to 1000 μM.

[0080] According to some embodiments of the present invention, the method for preparing a flexible sensor further includes the following steps.

[0081] Prepare multiple rutin solutions of standard concentrations.

[0082] The flexible sensor was electrochemically calibrated using a rutin solution. If the slope deviation between the calculated working curve and the standard curve was within 15%, the flexible sensor was considered to be working properly.

[0083] Specifically, after the electrode of the flexible sensor is cleaned, three standard rutin solutions with concentrations of 10 μM, 100 μM, and 500 μM are first tested for electrochemical calibration. If the slope deviation between the working curve and the standard curve is within 15%, the electrode is considered to be working normally.

[0084] The following describes the in vivo rutin detection method provided by the present invention. The in vivo rutin detection method described below and the flexible sensor for detecting rutin content described above can be used for reference in correspondence with each other.

[0085] See also Figure 5 As shown, the in vivo rutin detection method provided in this embodiment includes the following steps.

[0086] S510 , drilling holes at set positions on the surface of the plant leaf to be tested.

[0087] S520 , attaching the flexible sensor to the surface of the plant leaf to be tested, with the working electrode 210 facing the punched position.

[0088] S530, adding buffer solution to the punched position, then connecting to an electrochemical workstation, and detecting the concentration of rutin by chronoamperometry.

[0089] Experimental example

[0090] Taking tomatoes as an example, tomato juice was extracted and centrifuged at 8,000 to 10,000 rpm (preferably 10,000 rpm) for 5 to 10 minutes (preferably 10 rpm). The supernatant was collected and subjected to a recovery test. Simultaneously, the rutin content in the supernatant was measured using liquid chromatography-tandem mass spectrometry (LC-MS / MS) and compared with the real-time detection results using the electrochemical method of the present invention.

[0091] The results are shown in Table 1. The recoveries of rutin were between 98.22% and 102.05%, and the response current values at the same concentration were relatively consistent (n=3).

[0092] The results show that the detection results of this flexible electrode sensing method are reliable.

[0093] Table 1 Determination of sensor spike recovery (n=3)

[0094]

[0095] Real-time detection of living plants: Connect the flexible sensor to the electrochemical workstation and perform an IT scan (potential of 0.16 V to 0.20 V (preferably 0.18 V), sampling interval of 0.1 s). After stabilization in PBS (Phosphate Buffered Saline) for 10 min to 15 min (preferably 10 min), the living plant is tested (see Figure 6 Several small holes were punched into the leaves of living plants to release rutin. Due to its adhesive properties, the flexible sensor was fixed to the lower surface of the leaf, with the working electrode 210 of the flexible sensor facing the holes. 20 μL of PBS was dripped onto the holes to facilitate chemical connection between the working electrode 210 and the leaf. The current signal obtained was used to calculate the instantaneous concentration of the sample being tested using a calibrated working curve.

[0096] Comparative Example 1

[0097] Comparative Example 1 provides a flexible sensor for detecting rutin. The only difference in its preparation method from the above experimental example is that in Comparative Example 1, HfSe2 is replaced with an equal amount of NbSe2 to prepare the flexible sensor NbSe2-COOH-SWCNT-Nafion / MOF-818 / LIG / Ecoflex. The sensor was characterized by cyclic voltammetry (CV). The CV scan was performed at 1 mM [Fe(CN)6] 3- / 4- The current response of CV scan is shown in Figure 7 It can be seen that the flexible sensor prepared in Comparative Example 1 has a relatively small current and its detection effect is not as good as that of the above experimental examples.

[0098] Comparative Example 2

[0099] Comparative Example 2 provides a flexible sensor for detecting rutin. Its preparation method differs only from the above experimental examples in that the drop-coating modification of MOF-818 (the first modification layer) is omitted, and only HfSe2-COOH-SWCNT-Nafion (the second modification layer) is drop-coated. This yields a flexible sensor: HfSe2-COOH-SWCNT-Nafion / LIG / Ecoflex. As can be seen, the flexible sensor prepared in Comparative Example 2 exhibits a relatively low current flow, and its detection performance is inferior to that of the above experimental examples.

[0100] See also Figure 7 As shown, the flexible sensors of Comparative Examples 1 and 2 were 3- / 4− Cyclic voltammetry curves in solution. This figure shows that the current values of Comparative Examples 1 and 2 are significantly lower, indicating slower reaction rates. The flexible sensor of the experimental example exhibits better electrochemical performance. Therefore, the HfSe2-COOH-SWCNT-Nafion / MOF-818 / LIG / Ecoflex flexible sensor was used for rutin detection.

[0101] From the description of the above embodiments, it can be seen that the flexible sensor for detecting rutin content provided by the present invention can detect and analyze the rutin content in living plants (such as flowers, vegetables, trees, etc.) in real time, and the detection part is mainly the flat leaves of the plant. During detection, the flexible electrode can fit tightly to the surface of the plant leaves and maintain stable electrochemical properties under deformation, while having high sensitivity and specificity. It can quickly and accurately obtain the rutin content in the plant body, and realize long-term, stable and reliable monitoring of rutin in living plants. Through this technology, it provides an important theoretical basis and technical support for the cultivation of high-quality crops with high rutin content, and promotes the innovation and development of the field of crop breeding.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A flexible sensor for detecting rutin content, characterized in that: include: A flexible substrate and a graphene electrode unit, wherein the graphene electrode unit is provided on the flexible substrate; The graphene electrode unit includes a working electrode, a counter electrode, a reference electrode and a guide rail. The working electrode is provided with a first modification layer and a second modification layer from the inside to the outside. The first modification layer includes MOF-818 material, and the second modification layer includes HfSe2-COOH-SWCNT-Nafion material. The reference electrode is provided with an Ag / AgCl ink layer to form an Ag / AgCl reference electrode; The area where the guide rail is located is provided with a copolyester insulation layer; The flexible substrate is a copolyester flexible substrate.

2. A method for preparing the flexible sensor according to claim 1, characterized in that: include: The PI tape is patterned using a computer-controlled laser direct writer, and a graphene electrode unit body is obtained on the PI tape through induction; Transferring the graphene electrode unit body on the PI tape to the flexible substrate; Coating a set amount of Ag / AgCl ink on the exposed area of the reference electrode and heating and curing the ink to obtain an Ag / AgCl reference electrode; preparing a copolyester insulation layer in the area where the guide rail is located; The working electrode was modified to obtain a HfSe2-COOH-SWCNT-Nafion / MOF-818 / LIG / Ecoflex electrode.

3. The method for preparing a flexible sensor according to claim 2, wherein: The step of transferring the graphene electrode unit body on the PI tape to the flexible substrate comprises: Applying the Ecoflex mixed solution of a set ratio to the graphene electrode unit body on the PI tape by a spin coater, and then performing a vacuum drying and heating treatment; The graphene electrode unit body is peeled off from the PI tape to obtain the graphene electrode unit located on the flexible substrate.

4. The method for preparing a flexible sensor according to claim 2, wherein: The working electrode is modified to obtain a HfSe2-COOH-SWCNT-Nafion / MOF-818 / LIG / Ecoflex electrode, comprising: The working electrode was coated with a MOF-818 solution, and after the working electrode was dried, a HfSe2-COOH-SWCNT-Nafion solution was coated thereon. After the working electrode was dried, a HfSe2-COOH-SWCNT-Nafion / MOF-818 / LIG / Ecoflex electrode was obtained.

5. The method for preparing a flexible sensor according to any one of claims 2 to 4, characterized in that: Also includes: A rutin-phosphate buffer solution with a set concentration is configured to perform IT detection on the flexible sensor, and a set of standard curves between the concentration of the rutin-phosphate buffer solution and the logarithm of the current are obtained according to the detection results.

6. The method for preparing a flexible sensor according to claim 5, wherein: Also includes: Prepare multiple portions of rutin solution with standard concentration; The flexible sensor is electrochemically calibrated using the rutin solution. If the slope deviation between the calculated working curve and the standard curve is within 15%, the flexible sensor is considered to be working properly.

7. A method for detecting living rutin based on the flexible sensor according to claim 1, characterized in that: include: Punching holes at set positions on the surface of the plant leaves to be tested; The flexible sensor is attached to the surface of the plant leaf to be tested, and the working electrode is aligned with the punched position; Buffer solution was added dropwise to the punched position, and then the electrochemical workstation was connected to detect the concentration of rutin by chronoamperometry.

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