A Tb 3+ Method for preparing ZnMOF fluorescent sensor and application thereof

Abstract

The application relates to the technical field of MOF-based fluorescent sensor, in particular to a Tb 3+ @ZnMOF fluorescent sensor and an application thereof, aims to provide an MOF-based fluorescent sensor capable of detecting L-Pyr concentration, namely a Tb 3+ @ZnMOF fluorescent sensor and a preparation method thereof, which comprises the following steps: 1) completing activation pretreatment of ZnMOF; 2) immersing the activated and pretreated ZnMOF into a Tb(NO3)3 aqueous solution, stirring at room temperature for 20-24 hours, and then sequentially filtering, washing and vacuum drying the same, so as to obtain a Tb 3+ @ZnMOF fluorescent sensor, the sensor is capable of detecting L-Pyr concentration, and has the advantages of simple operation, rapid response, high detection sensitivity, reusability and low detection cost.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of MOF-based fluorescent sensors, and particularly relates to a preparation method of a Tb 3+ @ZnMOF fluorescent sensor and application thereof. BACKGROUND

[0002] Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by abnormal activation of the immune system, leading to multi-organ involvement, including the kidneys, skin, joints and other important organs, often causing severe and irreversible damage. Therefore, early diagnosis and intervention are crucial for improving the prognosis of SLE patients and ensuring health. L-pyroglutamic acid (L-Pyr) is an important biomarker for SLE, and its concentration is significantly elevated in SLE patients. Studies have shown that the average concentration of L-Pyr in SLE patients can reach 109.2-111.93 µM, while the average concentration in healthy people is only 50.47-52.66 µM. This significant concentration difference makes the detection of L-Pyr have important application reference value in the clinical monitoring and diagnosis of SLE. The detection of L-Pyr not only helps in the early diagnosis of SLE, but also can be used to evaluate the activity of the disease and the treatment effect. For example, during the active stage of the disease, the concentration of L-Pyr tends to further increase, while in the case of effective treatment, its concentration gradually decreases. Therefore, monitoring the changes in the concentration of L-Pyr can provide important reference information for clinicians, helping patients to develop more precise treatment plans.

[0003] However, traditional detection methods, including electrochemical methods, indantrione colorimetric method and high-performance liquid chromatography, all have problems such as low efficiency, high cost, complex operation procedures, etc. On the contrary, fluorescent sensors have the advantages of simple operation, low cost, good selectivity, fast response and high sensitivity. Currently, there are very few reports on specific detection of L-Pyr. This situation not only highlights the challenges in this field of research, but also emphasizes the importance and value of in-depth exploration.

[0004] Metal-organic frameworks (MOFs) are a class of highly ordered porous crystalline materials formed by self-assembly of metal ions or metal clusters and organic ligands through coordination bonds. Their unique structural characteristics include high porosity, large specific surface area, adjustable pore size and functionalization properties, as well as excellent chemical and thermal stability. As a new type of porous material, MOFs have shown great application potential in gas storage and separation, catalysis, sensing and biomedical fields. In recent years, MOFs have also received widespread attention in the field of fluorescent sensing, especially in the identification and detection of small biomolecules, providing new tools and methods for biomedical detection and disease diagnosis. However, there is currently no mature MOF-based fluorescent sensor that can be used to detect L-Pyr concentration. SUMMARY

[0005] The purpose of the present application is to provide a rare earth functionalized MOF-based fluorescent sensor capable of detecting L-Pyr concentration, i.e., a Tb 3+ Preparation method of ZnMOF fluorescent sensor and application thereof.

[0006] The present application is implemented by adopting the following technical solutions:

[0007] A Tb 3+ The preparation method of the ZnMOF fluorescent sensor comprises the following steps: 1) completing the activation pretreatment of the ZnMOF: soaking the ZnMOF (zinc metal organic framework) in anhydrous methanol for 3-4 days, wherein the ZnMOF is a ZnMOF rich in uncoordinated carboxylate (the crystallographic data of the ZnMOF rich in uncoordinated carboxylate is stored in the Cambridge Crystallographic Data Center, and the CCDC reference number is 1884039), then soaking it in dichloromethane for 3-4 days, and finally vacuum drying it to complete the activation pretreatment of the ZnMOF; 2) immersing the ZnMOF after the activation pretreatment in a Tb(NO3)3 aqueous solution, stirring it at room temperature for 20-24 hours, and then sequentially filtering, washing, and vacuum drying it to obtain a Tb 3+ ZnMOF fluorescent sensor.

[0008] Further, in the activation pretreatment process of the ZnMOF in step 1), the temperature during vacuum drying is 80°C, and the vacuum drying time is 4-8 h.

[0009] Further, the concentration of the Tb(NO3)3 aqueous solution is 0.1 mol / L.

[0010] Further, the vacuum drying temperature in step 2) is 80°C, and the vacuum drying time is 4-8 h.

[0011] A Tb 3+ ZnMOF fluorescent sensor prepared by the preparation method of the ZnMOF fluorescent sensor 3+ ZnMOF fluorescent sensor for detecting L-Pyr concentration.

[0012] The specific detection method is as follows: 1) concentration calculation and analysis detection: using the Stern-Volmer equation I 407 / I 545 = b+K sv [M]) to obtain the L-Pyr concentration M, wherein I 407 is the emission intensity of the Tb 3+ ZnMOF at 407 nm when reacting with L-Pyr, I 545 is the emission intensity of the Tb 3+The emission intensity at 545 nm when the ZnMOF reacts with L-Pyr, K sv is a slope constant and is 6.74 x 10 4 M −1 is an intercept constant and is 0.2081; 2) Convenient concentration estimation: when detecting, the L-Pyr solution to be detected is added to the Tb 3+ @ZnMOF fluorescent sensor surface, and then irradiated by a UV lamp, and the concentration range of L-Pyr can be quickly estimated by observing the color change of the Tb 3+ @ZnMOF under the irradiation of the UV lamp, that is, the fluorescence color gradually changes from green to blue with the increase of the concentration of L-Pyr. In some actual application scenarios, if only the concentration of L-Pyr needs to be quickly evaluated, and the detection conditions are limited, this method can be used for estimation.

[0013] The beneficial effects produced by the present application are as follows: the Tb 3+ @ZnMOF fluorescent sensor can be used for detecting the concentration of L-Pyr, and has the advantages of simple operation, rapid response, high detection sensitivity, reusability, and low detection cost. BRIEF DESCRIPTION OF DRAWINGS

[0014] The drawings incorporated into the specification and constituting a part of the specification, show embodiments consistent with the present application, and together with the specification, serve to explain the principles of the present application.

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows, and obviously, other drawings can also be obtained by those skilled in the art without creative labor.

[0016] Figure 1 The Tb 3+ @ZnMOF prepared by the present application;

[0017] Figure 2 The morphology diagram of the ZnMOF (2a-b) and Tb 3+ @ZnMOF (2c-d) described by the present application;

[0018] Figure 3 The test result diagram of experiment three;

[0019] Figure 4 The test result diagram of experiment four;

[0020] Figure 5 The test result diagram of experiment five;

[0021] Figure 6 Figure for test results of Experiment Six;

[0022] Figure 7 Figure for test results of Experiment Six;

[0023] Figure 8 Figure for test results of Experiment Seven;

[0024] Figure 9 Figure for test results of Experiment Seven;

[0025] Figure 10 Figure for test results of Experiment Eight;

[0026] Figure 11 Figure for test results of Experiment Nine. DETAILED DESCRIPTION

[0027] In order to enable every aspect of the present application to be clearer, the following will further describe the solutions of the present application. It should be explained that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0028] In the description, it should be explained that the terms “first”, “second” are only for the purpose of description, and cannot be understood as indicating or implying relative importance. It should be explained that, unless otherwise explicitly specified and limited, the terms “mounting”, “connecting”, “connection” should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0029] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein; obviously, the examples in the specification are only some of the embodiments of the present application, not all the embodiments.

[0030] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0031] A Tb 3+The preparation method of the ZnMOF fluorescence sensor includes the following steps: 1) Activation pretreatment of ZnMOF: ZnMOF (zinc metal-organic framework) is immersed in anhydrous methanol for 3-4 days, wherein the ZnMOF is rich in uncoordinated carboxylates (crystallographic data of ZnMOF rich in uncoordinated carboxylates are stored in the Cambridge Crystallographic Data Centre, CCDC reference number 1884039), and then immersed in dichloromethane for 3-4 days. Finally, it is vacuum dried at 80 ℃ for 4-8 h to complete the activation pretreatment of ZnMOF; 2) 100 mg of the activated pretreated ZnMOF is immersed in 30 mL of 0.1 mol / L Tb(NO3)3 aqueous solution and stirred at room temperature for 20-24 hours. Then, it is filtered, washed, and vacuum dried sequentially at 80 ℃ for 4-8 h to obtain Tb 3+ @ZnMOF fluorescence sensor.

[0032] Tb prepared as above 3+ The ZnMOF fluorescence sensor is used to detect L-Pyr concentration.

[0033] The specific detection methods are as follows: 1) Concentration calculation and analysis detection: using the Stern-Volmer equation I 407 / I 545 = b+K sv [M]) yields the L-Pyr concentration M, where I 407 For Tb 3+ The emission intensity at 407 nm during the reaction of ZnMOF with L-Pyr, I 545 For Tb 3+ The emission intensity at 545 nm during the reaction of ZnMOF with L-Pyr, K sv It is a slope constant and is 6.74 × 10⁻⁶. 4 M −1 1) b is the intercept constant and is 0.2081; 2) Convenient concentration estimation: During detection, the L-Pyr solution to be tested is added dropwise to Tb. 3+ @ZnMOF fluorescent sensor surface, then illuminated with ultraviolet light, and Tb was observed. 3+ The color change of @ZnMOF can quickly estimate the concentration range of L-Pyr; that is, as the concentration of L-Pyr increases, the fluorescence color under ultraviolet light gradually changes from green to blue. In some practical applications, when only a rapid assessment of the L-Pyr concentration is needed and detection conditions are limited, this method can be used for estimation.

[0034] To better verify Tb 3+Performance of ZnMOF fluorescent sensor, the following performance tests, analysis by the following experiments:

[0035] Experiment one: the Tb 3+ @ZnMOF fluorescent sensor obtained by the method prepared as above was analyzed: the Tb 3+ @ZnMOF fluorescent sensor was prepared by the preparation method as above. 3+ Functionalized ZnMOF fluorescent sensor, namely Tb 3+ @ZnMOF fluorescent sensor, such as Figure 1 as shown.

[0036] Experiment two: the Tb 3+ @ZnMOF fluorescent sensor obtained by the method prepared as above was analyzed: the Tb 3+ @ZnMOF was analyzed for morphology and structure: Figure 2 a-b (ZnMOF) and Figure 2 c-d (Tb 3+ @ZnMOF) SEM morphology analysis showed that the SEM morphology change was mainly due to the continuous physical stirring in the PSM preparation process.

[0037] Experiment three: the coordination of Tb 3+ @ZnMOF was characterized by XPS. As shown in Figure 3 a, the Tb 3+ @ZnMOF composite XPS spectrum showed the characteristic peaks of Tb 3+ . Specifically, the peaks corresponding to the binding energies of 1277.46 eV and 1243.84 eV were attributed to the 3d 3+ and 3d 3 / 2 spin-orbit splitting energy levels of Tb 5 / 2 , respectively. This confirmed that Tb 3+ was successfully incorporated into ZnMOF, as shown in Figure 3 b. Figure 3 The fine O1s spectrum of 3d showed that the range of C-O was from 530.86 eV (ZnMOF) to 531.20 eV (Tb 3+ @ZnMOF), and the range of C=O was from 531.83 eV (ZnMOF) to 532.58 eV (Tb 3+ @ZnMOF). These findings indicated that the incorporation of Tb 3+ was caused by the coordination interaction between Tb 3+ and the uncoordinated carboxyl group. This experiment showed that Tb 3+The PSM was successfully anchored on the uncoordinated carboxyl groups of ZnMOF through coordination, and the structure of ZnMOF framework did not change before and after PSM modification.

[0038] Experiment four: In order to further verify the Tb 3+ @ZnMOF material in the actual application scene and reliability, the water stability experiment is carried out. The core step of the experiment is to immerse the Tb 3+ @ZnMOF fluorescent sensor in water for different days, and detect its fluorescence intensity, as shown in Figure 4 The results show that the fluorescent sensor has extraordinary stability, which undoubtedly lays a solid foundation for the long-term application of Tb 3+ @ZnMOF fluorescent sensor in the actual clinical environment.

[0039] Experiment five: under the excitation wavelength of 254 nm, by adding different serum analytes on the Tb 3+ @ZnMOF fluorescent sensor, including potassium chloride (KCl), sodium chloride (NaCl), magnesium chloride (MgCl2), calcium chloride (CaCl2), ammonium chloride (NH4Cl), creatinine (Crea), creatine (Cre), sodium sulfate (Na2SO4), glutamic acid (Glu), valine (Val), glycine (Gly), urea (Urea), phenylalanine (Phe) and proline (Pro), the selectivity of Tb 3+ @ZnMOF fluorescent sensor to L-Pyr is evaluated. As shown in Figure 5 , the experiment shows that all the tested analytes except L-Pyr cannot trigger similar fluorescence effect. The results show that Tb 3+ @ZnMOF exhibits excellent selective recognition ability to L-Pyr.

[0040] Experiment six: in order to evaluate the anti-interference ability of Tb 3+ @ZnMOF in the actual complex environment, it is applied to the serum analyte solution without L-Pyr and the serum analyte solution containing L-Pyr for detection. Although there are many potential interference substances in the serum analyte solution, including common electrolytes in serum (such as potassium chloride (KCl), sodium chloride (NaCl), magnesium chloride (MgCl2), calcium chloride (CaCl2), ammonium chloride (NH4Cl)) and metabolites (such as creatinine (Crea), creatine (Cre), sodium sulfate (Na2SO4), glutamic acid (Glu), valine (Val), glycine (Gly), urea (Urea), phenylalanine (Phe) and proline (Pro)), but Tb 3+The ZnMOF fluorescent sensor still exhibits excellent selective recognition ability for L-Pyr, as shown in Figure 6 and 7 The experimental results show that the Tb 3+ @ZnMOF can effectively distinguish the target molecule L-Pyr from other interfering substances and maintain stable detection performance in complex biological matrix. This excellent anti-interference performance provides reliable guarantee for the accurate detection of L-Pyr, further proving the potential of the Tb 3+ @ZnMOF fluorescent sensor in actual clinical application.

[0041] Experiment seven: In order to further explore the sensitivity of the Tb 3+ @ZnMOF to L-Pyr, a concentration gradient titration experiment was carried out. As shown in Figure 8 , the Tb 3+ @ZnMOF fluorescent sensor exhibits extraordinary ability for L-Pyr detection. With the gradual increase of L-Pyr concentration from 0-85 µM, the emission peak intensity at 407 nm shows an upward trend, and the emission peak intensity at 545 nm shows a downward trend. The linear relationship between the emission intensity ratio at 407 nm and 545 nm and the molar concentration of L-Pyr was used for fitting, as shown in Figure 9 Through fitting, the relationship between the emission intensity ratio and the concentration of L-Pyr was obtained: I 407 / I 545 = 67440 ×[L-Pyr] + 0.2081, where I 407 and I 545 represent the luminescence intensity at 407 nm and 545 nm, respectively, and K sv = 6.74 ×10 4 M −1 represents the slope constant, and b = 0.2081 represents the intercept constant.

[0042] According to the K sv value and the standard error σ (σ = 1.0667 × 10 -3 ), the detection limit LOD (LOD = 3σ / K) of the Tb 3+ @ZnMOF fluorescent sensor for L-Pyr is 47.48 nM.

[0043] In addition, an interesting phenomenon appeared during the experiment: with the increase of L-Pyr concentration, the fluorescence color of the Tb 3+ @ZnMOF under 254 nm ultraviolet light gradually changed from green to blue, which can be used as a basis for estimating the concentration of L-Pyr.

[0044] Experiment eight: experimental exploration on detection response time, as shown in Figure 10 Figure 8, the response time can be as low as 1 minute. The results show that the Tb 3+ @ZnMOF fluorescent sensor is a kind of fast and convenient fluorescent detection platform.

[0045] Experiment nine: multiple cycle experiments to explore the reusability of Tb 3+ @ZnMOF fluorescent sensor when applied: after each detection cycle, Tb 3+ @ZnMOF fluorescent sensor is cleaned with distilled water, naturally air dried, and then used in the next cycle. After five consecutive and rigorous cycle tests, it was found that the rapid response ability of Tb 3+ @ZnMOF fluorescent sensor to L-Pyr did not weaken significantly, as shown in Figure 11 Figure 9. This series of experimental data not only solidly proves the excellent stability of Tb 3+ @ZnMOF fluorescent sensor after repeated use, but also fully demonstrates its excellent recovery ability and great potential for reuse.

[0046] The above is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Although detailed description is made with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions described in the foregoing embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments, and they should be covered in the protection scope of the claims.

Claims

1. A type of Tb 3+ The application of the ZnMOF fluorescence sensor is characterized by... The Tb 3+ @ZnMOF fluorescence sensor is used to detect L-Pyr concentration, Tb 3+ The preparation method of the ZnMOF fluorescence sensor includes the following steps: 1) Activation pretreatment of ZnMOF: ZnMOF is immersed in anhydrous methanol for 3-4 days, wherein the ZnMOF is rich in uncoordinated carboxylate, and then immersed in dichloromethane for 3-4 days. Finally, it is vacuum dried to complete the activation pretreatment of ZnMOF; 2) The activated ZnMOF is immersed in Tb(NO3)3 aqueous solution and stirred at room temperature for 20-24 hours, and then filtered, washed, and vacuum dried sequentially to obtain Tb 3+ @ZnMOF fluorescence sensor.

2. A Tb according to claim 1 3+ The application of the ZnMOF fluorescence sensor is characterized by... In step 1), during the activation pretreatment of ZnMOF, the temperature during vacuum drying is 80 ℃ and the vacuum drying time is 4-8 h.

3. A Tb according to claim 2 3+ The application of the ZnMOF fluorescence sensor is characterized by... The concentration of the Tb(NO3)3 aqueous solution is 0.1 mol / L.

4. A Tb according to claim 3 3+ The application of the ZnMOF fluorescence sensor is characterized by... The vacuum drying temperature in step 2) is 80 ℃, and the vacuum drying time is 4-8 h.

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