Preparation method and application of Tb < 3 + >-coated ZnMOF fluorescence sensor

Abstract

The invention relates to the technical field of MOF-based fluorescent sensors, in particular to a preparation method and application of a Tb < 3 + >-coated ZnMOF fluorescent sensor, and aims to provide an MOF-based fluorescent sensor capable of detecting L-Pyr concentration, namely the preparation method of the Tb < 3 + >-coated ZnMOF fluorescent sensor, which comprises the following steps: 1) completing activation pretreatment of ZnMOF; and 2) immersing the activated and pretreated ZnMOF in a Tb (NO3) 3 aqueous solution, stirring at room temperature for 20-24 hours, and then sequentially filtering, washing and vacuum drying to obtain the Tb < 3 + >-coated ZnMOF fluorescent sensor which can be used for detecting the concentration of L-Pyr and has the advantages of simplicity and convenience in operation, quick response, high detection sensitivity, reusability and low detection cost.

Description

Technical Field

[0001] The present invention relates to the technical field of MOF-based fluorescence sensors, and specifically to a Tb 3+ @Preparation method and application of ZnMOF fluorescence sensor. Background Art

[0002] Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by abnormal activation of the immune system, which leads 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 to improving the prognosis of SLE patients and protecting their health. L-pyroglutamate (L-Pyr), as an important biomarker for SLE, has a significantly increased concentration 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 can also be used to evaluate the activity of the disease and the efficacy of treatment. For example, during the active stage of the disease, the concentration of L-Pyr tends to increase further, while when the treatment is effective, its concentration will gradually decrease. Therefore, monitoring changes in L-Pyr concentration can provide important reference information for clinicians and help patients develop more accurate treatment plans.

[0003] However, traditional detection methods, including electrochemical methods, ninhydrin colorimetry, and high-performance liquid chromatography, have problems such as low efficiency, high cost, and complicated operating procedures. In contrast, fluorescent sensors have the advantages of simple operation, low cost-effectiveness, good selectivity, fast response, and high sensitivity. Currently, reports on the specific detection of L-Pyr are extremely rare. This situation not only highlights the challenges of research in this field, but also emphasizes the importance and value of in-depth exploration.

[0004] Metal-organic frameworks (MOFs) are highly ordered porous crystalline materials formed by self-assembly of metal ions or metal clusters and organic ligands through coordination bonds. Their unique structural features include high porosity, large specific surface area, adjustable pore size and functional properties, and excellent chemical and thermal stability. As an emerging class of porous materials, MOFs have shown great application potential in gas storage and separation, catalysis, sensing, and biomedicine. In recent years, MOFs have also received widespread attention in the field of fluorescence sensing, especially in the identification and detection of small biomolecules, providing new tools and methods for biomedical testing and disease diagnosis. However, no mature MOF-based fluorescence sensors have been discovered and prepared for the detection of L-Pyr concentration. Summary of the invention

[0005] The purpose of the present invention is to provide a rare earth functionalized MOF-based fluorescence sensor that can be used to detect the concentration of L-Pyr, namely a Tb 3+ @Preparation method and application of ZnMOF fluorescence sensor.

[0006] The present invention is achieved by adopting the following technical solutions: A Tb 3+ The preparation method of the @ZnMOF fluorescent sensor comprises the following steps: 1) completing the activation pretreatment of ZnMOF: immersing the ZnMOF (zinc metal organic framework) in anhydrous methanol for 3-4 days, wherein the ZnMOF is ZnMOF rich in uncoordinated carboxylates ((the crystallographic data of ZnMOF rich in uncoordinated carboxylates are stored in the Cambridge Crystallographic Data Center, CCDC reference number is 1884039)), and then immersing it in dichloromethane for 3-4 days, and finally vacuum drying it to complete the activation pretreatment of ZnMOF; 2) immersing the activated pretreated ZnMOF in Tb(NO 3 ) 3 The aqueous solution is stirred at room temperature for 20-24 hours, and then filtered, washed, and vacuum dried in sequence to obtain Tb 3+ @ZnMOF fluorescence sensor.

[0007] Furthermore, in step 1), during the activation pretreatment of ZnMOF, the vacuum drying temperature is 80° C. and the vacuum drying time is 4-8 h.

[0008] Furthermore, Tb(NO 3 ) 3 The concentration of the aqueous solution is 0.1 mol / L.

[0009] Furthermore, the vacuum drying temperature in step 2) is 80°C, and the vacuum drying time is 4-8 h.

[0010] As mentioned above, a Tb 3+ @ZnMOF fluorescence sensor preparation method prepared a Tb 3+ @ZnMOF fluorescence sensor for detecting L-Pyr concentration.

[0011] The specific detection methods are as follows: 1) Concentration calculation and analysis: Using the Stern-Volmer equation I 407 / I 545 = b+K sv [M]) to obtain the L-Pyr concentration M, where I 407 Tb 3+@ZnMOF and L-Pyr reacted at 407 nm, I 545 Tb 3+ @ZnMOF and L-Pyr reacted with the emission intensity at 545 nm, K sv is the slope constant and is 6.74 × 10 4 M −1 , b is the intercept constant and is 0.2081; 2) Convenient concentration estimation: During the test, the L-Pyr solution to be tested is added dropwise to Tb 3+ @ZnMOF fluorescent sensor surface, and then irradiated with ultraviolet light, and observed Tb 3+ @ZnMOF’s color change 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 application scenarios, if only a quick assessment of the concentration of L-Pyr is required and the detection conditions are limited, this method can be used for estimation.

[0012] The beneficial effects of the present invention are as follows: Tb prepared by the preparation method 3+ @ZnMOF fluorescence sensor can be used to detect L-Pyr concentration, and has the advantages of simple operation, rapid response, high detection sensitivity, reusability and low detection cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0015] Figure 1 The Tb prepared by the present invention 3+ @ZnMOF; Figure 2 The ZnMOF (2a-b) and Tb 3+ @Morphology of ZnMOF (2c-d); Figure 3 This is the test result diagram of Experiment 3; Figure 4 This is the test result diagram of Experiment 4; Figure 5 This is the test result diagram of Experiment 5; Figure 6 This is the test result diagram of Experiment 6; Figure 7 This is the test result diagram of Experiment 6; Figure 8 This is the test result diagram of Experiment 7; Fig. 9 This is the test result diagram of Experiment 7; Fig.10 This is the test effect diagram of Experiment 8; Fig.11 This is the test effect diagram of Experiment 9. DETAILED DESCRIPTION

[0016] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0017] In the description, it should be noted that the terms "first" and "second" are only used for descriptive purposes and should not be understood as indicating or implying relative importance. It should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0018] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0019] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0020] A Tb 3+The preparation method of @ZnMOF fluorescent sensor includes the following steps: 1) completing the activation pretreatment of ZnMOF: soaking ZnMOF (zinc metal organic framework) in anhydrous methanol for 3-4 days, wherein ZnMOF is ZnMOF rich in uncoordinated carboxylates (the crystallographic data of ZnMOF rich in uncoordinated carboxylates are stored in the Cambridge Crystallographic Data Center, CCDC reference number is 1884039), and then soaking it in dichloromethane for 3-4 days, and finally vacuum drying it, the vacuum drying temperature is 80 ° C, and the vacuum drying time is 4-8 h, thereby completing the activation pretreatment of ZnMOF; 2) immersing 100 mg of ZnMOF after activation pretreatment in 30 mL of Tb(NO 3 ) 3 The aqueous solution is stirred at room temperature for 20-24 hours, and then filtered, washed, and vacuum dried in sequence. The vacuum drying temperature is 80 ° C and the vacuum drying time is 4-8 h, thereby obtaining Tb 3+ @ZnMOF fluorescence sensor.

[0021] Tb prepared as above 3+ @ZnMOF fluorescence sensor was used to detect L-Pyr concentration.

[0022] The specific detection methods are as follows: 1) Concentration calculation and analysis: Using the Stern-Volmer equation I 407 / I 545 = b+K sv [M]) to obtain the L-Pyr concentration M, where I 407 Tb 3+ @ZnMOF and L-Pyr reacted at 407 nm, I 545 Tb 3+ @ZnMOF and L-Pyr reacted to emit light at 545 nm, K sv is the slope constant and is 6.74 × 10 4 M −1 , b is the intercept constant and is 0.2081; 2) Convenient concentration estimation: During the test, the L-Pyr solution to be tested is added dropwise to Tb 3+ @ZnMOF fluorescent sensor surface, and then irradiated with ultraviolet light, and observed Tb 3+ @ZnMOF’s color change 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 application scenarios, if only a quick assessment of the concentration of L-Pyr is required and the detection conditions are limited, this method can be used for estimation.

[0023] To better verify Tb 3+ @The performance of ZnMOF fluorescence sensor is tested and analyzed through the following experiments: Experiment 1: Tb prepared as above 3+ @ZnMOF fluorescence sensor analysis: Tb 3+ Tb was successfully prepared by precisely anchoring it in ZnMOF rich in uncoordinated carboxylates. 3+ Functionalized ZnMOF fluorescent sensor, namely Tb 3+ @ZnMOF fluorescent sensor, such as Figure 1 shown.

[0024] Experiment 2: Tb prepared as above 3+ @ZnMOF fluorescence sensor morphology and structure analysis: The Tb 3+ @ZnMOF morphology and structure analysis: Figure 2 ab (ZnMOF) and Figure 2 cd (Tb 3+ @ZnMOF) showed that the SEM morphology changes were mainly attributed to the continuous physical stirring during the preparation process of PSM.

[0025] Experiment 3: XPS analysis of Tb 3+ The coordination with ZnMOF was characterized. Figure 3 As shown in a, Tb 3+ The comprehensive XPS spectrum of @ZnMOF clearly shows that Tb 3+ Specifically, the peaks corresponding to the binding energies of 1277.46 eV and 1243.84 eV are attributed to Tb 3+ 3D 3 / 2 and 3D 5 / 2 The spin-orbit splitting energy level confirms that Tb 3+ Successfully incorporated into ZnMOF, such as Figure 3 As shown in b. Figure 3 The detailed O1s spectra of c and 3d show that the CO ranges from 530.86 eV (ZnMOF) to 531.20 eV (Tb 3+ @ZnMOF), C=O ranges from 531.83 eV (ZnMOF) to 532.58 eV (Tb 3+ @ZnMOF). These findings suggest that Tb 3+ The incorporation of Tb 3+ The experiment shows that Tb 3+It was successfully anchored on the uncoordinated carboxyl group of ZnMOF through coordination, and the structure of the ZnMOF framework did not change before and after PSM modification.

[0026] Experiment 4: In order to further verify Tb 3+ @ZnMOF materials in practical application scenarios, the long-term durability and reliability of water stability experiments have been carried out. The core step of this experiment is to convert Tb 3+ @After the ZnMOF fluorescent sensor was immersed in water for different days, its fluorescence intensity was detected, such as Figure 4 The results show that the fluorescent sensor has extraordinary stability, which is undoubtedly the 3+ @This lays a solid foundation for the long-term application of ZnMOF fluorescent sensors in actual clinical settings.

[0027] Experiment 5: Under the condition of 254 nm excitation wavelength, by 3+ Different serum analytes, including potassium chloride (KCl), sodium chloride (NaCl), magnesium chloride (MgCl 2 ), calcium chloride (CaCl 2 ), ammonium chloride (NH 4 Cl), creatinine (Crea), creatine (Cre), sodium sulfate (Na 2 SO 4 ), glutamic acid (Glu), valine (Val), glycine (Gly), urea (Urea), phenylalanine (Phe) and proline (Pro), evaluate Tb 3+ @ZnMOF fluorescence sensor selectivity for L-Pyr. Figure 5 As shown in the experiment, all other analytes tested except L-Pyr failed to induce similar fluorescence effects. The results show that compared with other common components in serum, Tb 3+ @ZnMOF exhibits excellent selective recognition ability for L-Pyr.

[0028] Experiment 6: To evaluate Tb 3+ @ZnMOF's anti-interference ability in actual complex environments is now applied to the detection of serum analytes without L-Pyr and serum analyte solutions containing L-Pyr. Although there are many potential interfering substances in the serum analyte solution, including common electrolytes in serum (such as potassium chloride (KCl), sodium chloride (NaCl), magnesium chloride (MgCl 2 ), calcium chloride (CaCl 2 ), ammonium chloride (NH 4Cl) and metabolites (such as creatinine (Crea), creatine (Cre), sodium sulfate (Na 2 SO 4 ), glutamic acid (Glu), valine (Val), glycine (Gly), urea (Urea), phenylalanine (Phe) and proline (Pro)), but Tb 3+ @ZnMOF fluorescent sensor still showed excellent selective recognition ability for L-Pyr, such as Figure 6 and 7 As shown, the experimental results show that Tb 3+ @ZnMOF can effectively distinguish the target molecule L-Pyr from other interfering substances and maintain stable detection performance in complex biological matrices. This excellent anti-interference performance provides a reliable guarantee for the accurate detection of L-Pyr, further proving that Tb 3+ @The potential of ZnMOF fluorescent sensors in practical clinical applications.

[0029] Experiment 7: To further explore Tb 3+ @ZnMOF's sensitivity to L-Pyr was tested by concentration gradient titration. Figure 8 As shown, Tb 3+ @ZnMOF fluorescence sensor showed extraordinary ability to detect L-Pyr. With the gradual increase of L-Pyr concentration, from 0-85 µM, the emission peak intensity at 407 nm showed an upward trend, and the emission peak intensity at 545 nm showed 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 fitted, as shown in Figure 2. Fig. 9 As shown, through fitting, the relationship between the emission intensity ratio and the L-Pyr concentration was obtained: 407 / I 545 = 67440 × [L-Pyr] + 0.2081, where I 407 with I 545 represent the luminescence intensity at 407 nm and 545 nm respectively, while K sv = 6.74 × 10 4 M −1 represents the slope constant, and b = 0.2081 represents the intercept constant.

[0030] According to K sv The value and standard error σ (σ = 1.0667 × 10 -3 ) It can be seen that Tb 3+ @The detection limit LOD (LOD = 3σ / K) of ZnMOF fluorescence sensor for L-Pyr is 47.48 nM.

[0031] In addition, an interesting phenomenon occurred during the experiment: as the concentration of L-Pyr increased, Tb 3+ @ZnMOF's fluorescence color gradually changes from green to blue under 254 nm ultraviolet light, which can be used as a basis for estimating the concentration of L-Pyr.

[0032] Experiment 8: Experimental exploration of detection response time, such as Fig.10 As shown, the response time can be as low as 1 minute. 3+ @ZnMOF fluorescence sensor is a fast and convenient fluorescence detection platform.

[0033] Experiment 9: Tb 3+ The reusability of @ZnMOF fluorescence sensor was explored by multiple cycles: after each detection cycle, Tb 3+ @ZnMOF fluorescent sensor is cleaned, air-dried, and then used in the next cycle. After five consecutive rigorous cycle tests, it was found that Tb 3+ The rapid response of ZnMOF fluorescence sensor to L-Pyr did not show any significant weakening. Fig.11 This series of experimental data not only firmly proves that Tb 3+ The excellent stability of @ZnMOF fluorescent sensor after repeated use also fully demonstrates its excellent recovery ability and huge reuse potential.

[0034] The above is only a specific implementation of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions are given with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein 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 all be covered by the protection scope of the claims.

Claims

1. A Tb 3+ @The preparation method of ZnMOF fluorescent sensor is characterized in that: The method comprises the following steps: 1) completing the activation pretreatment of ZnMOF: soaking the ZnMOF in anhydrous methanol for 3-4 days, wherein the ZnMOF is ZnMOF rich in uncoordinated carboxylate, and then soaking it in dichloromethane for 3-4 days, and finally vacuum drying it to complete the activation pretreatment of ZnMOF; 2) immersing the activated pretreated ZnMOF in a Tb(NO3)3 aqueous solution, stirring it at room temperature for 20-24 hours, and then filtering, washing, and vacuum drying it in sequence, thereby obtaining Tb 3+ @ZnMOF fluorescence sensor.

2. A Tb according to claim 1 3+ @The preparation method of ZnMOF fluorescent sensor is characterized in that: In step 1), during the activation pretreatment of ZnMOF, the vacuum drying temperature is 80 °C and the vacuum drying time is 4-8 h.

3. A Tb according to claim 2 3+ @The preparation method of ZnMOF fluorescent sensor is characterized in that: The concentration of Tb(NO3)3 aqueous solution is 0.1 mol / L.

4. A Tb according to claim 3 3+ @The preparation method of ZnMOF fluorescent sensor is characterized in that: The vacuum drying temperature in step 2) is 80°C and the vacuum drying time is 4-8 h.

5. A Tb as claimed in any one of claims 1 to 4 3+ @ZnMOF fluorescent sensor preparation method prepared by Tb 3+ @The application of ZnMOF fluorescence sensor is characterized by: The Tb 3+ @ZnMOF fluorescence sensor was used to detect L-Pyr concentration.

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