Metal organic framework material with double ligands and application of metal organic framework material in detection of DPA
Eu-MOF prepared through the dual ligand strategy solves the problems of cross-interference and background interference in the detection of fluorescent probes, and achieves high sensitivity and specific DPA detection, simplifies the process and reduces costs, and provides efficient Detection method.
Patent Information
- Application Number
- CN202411697313.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-25
- Publication Date
- 2025-01-07
AI Technical Summary
Existing fluorescent probes are difficult to avoid cross-interference when detecting different analytes. Especially in the complex context of water environments, it affects the accuracy and authenticity of the detection results, and there is still room for improvement in sensitivity and cost.
Eu-MOF prepared by a dual ligand strategy was synthesized by a simple one-step solvothermal method to form a metal organic frame material with three emission peaks. It is used to develop ratio-type fluorescent probes and use DPA's antenna effect design to achieve the Specific detection of DPA.
The emission peak fluorescence intensity ratio of 450 and 621 nm at 255 nm excitation wavelength increases with DPA concentration, providing high sensitivity and specific detection performance, simplifying the detection process, reducing costs, and improving the visualization effect of detection.
Smart Images
Figure CN119264458A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of ratiometric detection probes, and in particular relates to a metal organic framework material with dual ligands and an application thereof in the detection of DPA. Background Art
[0002] Bacillus anthracis is a Gram-positive, rod-shaped, spore-forming bacterium that can cause anthrax, a very dangerous infectious disease for humans and animals. 4 If not treated in time, it will lead to death. As the main component of anthrax spores, dipicolinic acid (DPA) is considered to be a unique biomarker of Bacillus anthracis. Therefore, it is urgent to develop an effective method for the rapid, sensitive and accurate determination of DPA content.
[0003] At present, people have explored a variety of methods for detecting DPA, such as high performance liquid chromatography, immunoassay, luminescence detection, etc. Luminescence detection has attracted much attention due to its advantages such as high sensitivity, convenient detection, fast response speed and good specificity. On this basis, many fluorescent probes have been developed and proved to be efficient tools for sensing and detection in health care, environmental protection, industrial and agricultural production, security and defense sectors. Fluorescence sensors have the advantages of simple operation, high sensitivity, portability, high efficiency and low cost, and have great application potential. Among the many photoluminescent sensing materials, lanthanide metal organic frameworks (Ln-MOFs) have unique optical properties such as long fluorescence lifetime, high color purity and large Stokes shift. At the same time, the highly coordinated lanthanide central ions in Ln-MOFs can accurately identify DPA and provide coordination sites to form stable complexes. However, most fluorescent probes show the same fluorescence signal for different analytes, and it is difficult to avoid cross-interference between different analytes; the complexity and diversity of the water environment make it have a large background interference in the detection process, affecting the accuracy and authenticity of the results. Therefore, people are committed to developing lanthanide metal-organic frameworks with better detection performance and higher sensitivity. Summary of the invention
[0004] In view of the defects existing in the prior art, the present invention provides a preparation method and application of Eu-MOF with a dual-emission strategy, which not only has a simple synthesis method, but also has the advantages of good specificity, low cost, and visualization of detection. This application can be used for the specific detection of DPA.
[0005] This application is implemented by adopting the following technical solutions:
[0006] The first object of the present application is to protect a metal organic framework material with dual ligands, the raw materials of which include pyromellitic acid (H4betc), 2-aminoterephthalic acid (BDC-NH2), and europium; in some embodiments of the present invention, the molar ratio of pyromellitic acid to 2-aminoterephthalic acid is 2-4:1-3;
[0007] And / or, the europium comprises europium chloride.
[0008] In some preferred embodiments of the present invention, at an excitation wavelength of 255 ± 10 nm, the prepared MOF has three emission peaks at 450, 605, and 621 nm, respectively;
[0009] And / or, the metal organic framework material is a sheet structure with a particle size of 200-300nm.
[0010] The second purpose of the present application is to protect the preparation method of the above-mentioned metal organic framework material with dual ligands, which comprises mixing the raw materials thoroughly, reacting at 35°C-40°C, cooling after the reaction, washing and drying to obtain the material.
[0011] In some embodiments of the present invention, the reaction time is 1 h-4 h;
[0012] And / or, washing is performed by using ethanol or water for multiple times.
[0013] The third purpose of the present application is to protect the use of the above-mentioned metal-organic framework material with a dual-ligand strategy or the metal-organic framework material prepared by the above-mentioned preparation method in the detection of DPA.
[0014] The fourth object of the present application is to protect a ratiometric fluorescent probe, comprising the above-mentioned metal-organic framework material with dual ligands or the metal-organic framework material prepared by the above-mentioned preparation method.
[0015] In some embodiments of the present invention, the mass concentration of the metal organic framework material is 0.001-0.006 mg / mL.
[0016] The fifth object of the present application is to protect the application of the above-mentioned ratiometric fluorescent probe in the quantitative detection of DPA.
[0017] In some embodiments of the present invention, the ratio of the fluorescence intensity at the 621 nm to 450 nm emission peaks increases with increasing DPA concentration.
[0018] Beneficial effects of the present invention:
[0019] The present invention prepares Eu-MOF by a simple one-step solvothermal method, such as Figure 1The preparation method of the present invention is simple, the materials are easy to obtain, and the prepared MOF has good dispersibility and high stability, showing excellent luminescence properties. 3+ The sensitization mechanism of the MOF was designed with a ratiometric fluorescent probe with a dual ligand strategy. Under an excitation wavelength of 255 nm, the prepared MOF had three emission peaks at 450, 605, and 621 nm. DPA can significantly enhance the fluorescence intensity at 621 nm, while the fluorescence intensity at 450 nm remains basically unchanged. In addition, the ratio of the fluorescence intensity at the emission peaks of 621 nm to 450 nm (I 621 / I 450 ) increases with the increase of DPA concentration. This MOF provides a feasible strategy for the assembly of dual-ligand MOFs with a simple preparation process and excellent sensing performance, opening up a new way to develop sensors for visual detection of DPA. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.
[0021] Figure 1 A schematic diagram of the preparation method and application process of the Eu-MOF ratiometric fluorescent probe with a dual-emission strategy provided by the present invention;
[0022] Figure 2 is the transmission electron microscope (TEM) image of Eu-MOF;
[0023] Figure 3 is the scanning electron microscope (SEM) image of Eu-MOF;
[0024] Figure 4 is the fluorescence excitation (Ex) spectra of Eu-MOF and ligands;
[0025] Figure 5 is the fluorescence emission (Em) spectra of Eu-MOF and ligands;
[0026] Figure 6 It is I under 235-290nm excitation 621 / I 450 The intensity ratio diagram of
[0027] Figure 7 This is the fluorescence intensity graph of the Eu-MOF solution stored at room temperature for five days;
[0028] Figure 8 is the fluorescence intensity of Eu-MOF solution stored at room temperature for five days (I 621 / I 450 ) ratio diagram;
[0029] Fig. 9 is the fluorescence lifetime diagram of Eu-MOF before and after adding DPA;
[0030] Fig.10 It is the ratio diagram of the fluorescence intensity of Eu-MOF to different ions, where the concentration of metal ions is 20 μM;
[0031] Fig.11 are the Fourier transform infrared spectra (FT-IR) of BDC-NH2, H4betc, Eu-MOF and Eu-MOF+DPA;
[0032] Fig.12 X-ray photoelectron spectra of Eu-MOF before and after the addition of DPA;
[0033] Fig.13 is the X-ray photoelectron spectrum of N1s of Eu-MOF before and after adding DPA;
[0034] Fig.14 is the X-ray photoelectron spectrum of Eu 3d of Eu-MOF before and after adding DPA;
[0035] Fig.15 is the X-ray photoelectron spectrum of O1s of Eu-MOF before and after adding DPA;
[0036] Fig.16 is the concentration optimization bar graph of Eu-MOF;
[0037] Fig.17 is the pH condition optimization bar graph of Eu-MOF;
[0038] Fig.18 Eu-MOF fluorescent probe is applied to DPA detection, and the response curve of fluorescence intensity to DPA concentration;
[0039] Fig.19 is the fluorescence intensity ratio (I 621 / I 450 ) and the linear relationship between DPA concentration; wherein, I 450 and I 621 are the fluorescence intensity of Eu-MOF at 450 nm and 621 nm, respectively;
[0040] Fig. 20 It is a linear curve of DPA concentration and R / B value. DETAILED DESCRIPTION
[0041] In order to make the purpose and technical solution of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings. The experimental methods described in the following examples are all conventional methods unless otherwise specified; if no specific techniques or conditions are specified in the examples, they are carried out according to the techniques or conditions described in the literature in the field or according to the product instructions; the reagents and materials, unless otherwise specified, can be obtained from commercial channels.
[0042] Example 1
[0043] Preparation method of visual ratiometric fluorescent probe with dual ligands:
[0044] 1) At room temperature, 84.72 mg of pyromellitic acid (0.33 mmol) and 30.19 mg of 2-aminoterephthalic acid (0.17 mmol) were dissolved in 15 ml of ethanol solution, and 139 μL of triethylamine solution was added.
[0045] 2) Dissolve 91.5 mg of europium chloride hexahydrate (0.25 mmol) in 5 mL of ultrapure water and sonicate for 5 min until fully dissolved.
[0046] 3) The solutions obtained in 1) and 2) were mixed evenly in a round-bottom flask, heated in a water bath at 40°C and stirred for 2 hours. The obtained suspension was centrifuged and washed, and the washed precipitate was dried in a vacuum drying oven at 40°C for 12 hours.
[0047] Example 2 Detection and Analysis of Fluorescent Probe Properties
[0048] Morphology analysis:
[0049] Figure 2 This is the transmission electron microscope (TEM) of Eu-MOF. It can be seen from the figure that the prepared Eu-MOF has good dispersibility and uniform size distribution. The average size of Eu-MOF is 268nm.
[0050] Figure 3 This is a scanning electron microscope (SEM) image of the prepared Eu-MOF. It is clearly seen from the image that when the H4betc / BDC-NH2 ratio is 2:1, the MOF presents a regular flake structure with an average diameter of 268nm. This structure increases the specific surface area of the reaction and makes the reaction proceed more thoroughly.
[0051] Excitation and emission analysis
[0052] Figure 4-5 This is the excitation and emission spectrum of the prepared Eu-MOF. It can be clearly seen from the figure that the excitation wavelength of Eu-MOF is about 255nm, with a fluorescence peak at 450nm, and two fluorescence emission peaks at 605nm and 621nm.
[0053] Figure 6 Under 235-290nm excitation, 621 / I 450 It is clear from the figure that when the excitation wavelength is 255nm, I 621 / I 450 The ratio is the smallest.
[0054] Figure 7-8 This is a stability test of Eu-MOF dissolved in HEPES buffer solution and stored at room temperature for five days. It can be clearly seen from the figure that the fluorescence intensity and fluorescence intensity ratio (I 621 / I 450 ) remained basically unchanged, proving that Eu-MOF has good stability.
[0055] Example 3 Detection of DPA by fluorescent probe
[0056] The fluorescence detection of DPA was carried out in a 2 mL centrifuge tube. First, 25 μL (400 μg / mL) of Eu-MOF and 975 μL of HEPES buffer solution were mixed. Then 1000 μL of DPA of different concentrations were added in sequence, mixed evenly and reacted at room temperature for 1 min. Finally, the fluorescence spectrum was recorded with an excitation wavelength of 255 nm. The fluorescence intensity (I 621 / I 450 ) ratio to perform quantitative detection of DPA.
[0057] Fig. 9 is the fluorescence lifetime of Eu-MOF with and without DPA. Before adding DPA, the average fluorescence lifetime of Eu-MOF was 102.70μs, while after adding DPA, the average fluorescence lifetime of Eu-MOF became 411.48μs. The results show that the addition of DPA enhances the fluorescence intensity at 621nm.
[0058] Fig.10 This is the response degree of Eu-MOF to different ions, where the concentration of metal ions is 20 μM. As shown in the figure, Eu-MOF responds to different ions to different degrees, so this fluorescent probe can specifically detect DPA.
[0059] Fig.11 The Fourier transform infrared spectra (FT-IR) of H4betc, BDC-NH2, Eu-MOF and Eu-MOF+DPA are shown in the figure. As shown in the figure, Eu-MOF has a high concentration of 2500-3000 cm -1 The wide band at 1704 cm-1 disappeared, proving that H4betc and BDC-NH2 were deprotonated to synthesize MOF. -1and 1683cm -1 The C=O stretching vibration peak appears at 1542 cm -1 At the same time, H4betc and BDC-NH2 at 1274 cm -1 and 1230cm -1 The CO stretching vibration peak at 100° disappears. These changes reveal that the carboxyl group and Eu 3+ The coordination of ions formed Eu-MOF. The adsorption peak position of Eu-MOF was basically consistent with that of Eu-MOF+DPA, which further proved that the type of functional groups of Eu-MOF did not change significantly during the reaction.
[0060] Figure 12-15 The following are the X-ray photoelectron spectroscopy (XPS) graphs of Eu-MOF and N1s, Eu 3d and O1s. The XPS graph shows that there are four elements, C, N, O and Eu, in Eu-MOF. The binding energy of N 1s changes from 401.3eV of Eu-MOF to 400.9eV, which indicates that the electron cloud density around N has changed due to the formation of NH…O hydrogen bonds. After adding DPA, the two peaks of Eu 3d at 1135.8eV and 1165.5eV shifted to 1135.1eV and 1164.9eV, respectively, and the O 1s peak shifted from 531.7eV to 533eV. The changes in the binding energies of O 1s and Eu 3d indicate that Eu 3+ The coordination with DPA changes the electron cloud density around the coordinated O atoms in the ligand. Based on these conclusions, it is proved that the detection mechanism of Eu-MOF for DPA is the antenna effect of energy transfer.
[0061] Fig.16 is the concentration optimization curve of Eu-MOF of the embodiment of the present invention. As can be seen from the figure, when DPA is added to 5 μg / mL Eu-MOF solution, the fluorescence intensity (I 621 / I 450 ) changes most obviously, and the detection effect is the best.
[0062] Fig.17 The fluorescence response of Eu-MOF and Eu-MOF after adding DPA in various pH environments (pH 5.0-pH 10.0) is shown. The ratio of the fluorescence intensity of Eu-MOF (I 621 / I 450 ) gradually increased in the pH range of 5.0 to 7.4, but as the pH value increased from 7.4 to 10.0, the ratio of fluorescence intensity (I 621 / I 450 ) gradually decreased. Since 7.4 is the physiological pH value, we selected pH 7.4 as the optimal pH value for detecting DPA.
[0063] Figure 18-19 The response curve and linear curve of the Eu-MOF with dual emission strategy implemented in the present invention to DPA in the concentration range of 0-30 μM. Under the optimal conditions, the quantitative detection of DPA was carried out. As the concentration of DPA increased, the fluorescence intensity of Eu-MOF at 621 nm gradually increased, while the fluorescence intensity at 450 nm remained basically unchanged. Correspondingly, I 621 / I 450 It gradually increases with the increase of DPA concentration, which shows that the proposed method is feasible for the fluorescence detection of DPA. Fig.19 is the relationship between DPA concentration and I 621 / I 450 The linear curve of (the ratio of fluorescence intensity at 621nm and 450nm emission peak) is Fig.19 It can be seen that the Eu-MOF has good linearity for DPA, and the linear range is 0 to 30 μM. This shows that the Eu-MOF with a dual emission strategy in the embodiment of the present invention can be successfully applied to ratiometric fluorescence detection of DPA.
[0064] Fig. 20 The fluorescence color change photos obtained under UV light were processed in the RGB color space through a smartphone application (swatches) to obtain the R / B value, and a linear curve of DPA concentration and R / B value was obtained. As can be seen from the figure, R / B and DPA have good linearity, and the linear range is 0 to 15μM, indicating that the Eu-MOF ratio fluorescence probe with a dual-emission strategy can be successfully used with a smartphone platform, making detection easier and faster.
[0065] Table 1. Results of recovery of DPA in actual samples
[0066]
[0067] Table 1 shows that the recoveries of DPA in real water samples range from 97.30% to 104.0%, and the relative standard deviation (RSD) is less than 4.40%. The results show that the Eu-MOF ratiometric fluorescent probe with dual emission strategy has great potential for visual quantitative detection of DPA in real samples.
[0068] Of course, the above are only preferred embodiments of the present method and are not intended to limit the present method. Although the present method is described in detail with reference to the above method, those skilled in the art can still modify the above-described technical solutions or replace some of the technical features with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present method shall be included in the protection scope of the present invention.
Claims
1. A metal organic framework material with dual ligands, characterized in that: The raw materials include pyromellitic acid, 2-aminoterephthalic acid and europium.
2. The metal organic framework material with a dual ligand strategy according to claim 1, characterized in that: The molar ratio of pyromellitic acid to 2-aminoterephthalic acid is 2:1; And / or, the europium comprises europium chloride.
3. The metal organic framework material with dual ligands according to claim 1, characterized in that: At an excitation wavelength of 255 ± 10 nm, the prepared MOF has three emission peaks at 450, 605, and 621 nm; And / or, the metal organic framework material is a sheet structure with a particle size of 200-300nm.
4. A method for preparing a metal organic framework material with dual ligands, characterized in that: The raw materials described in any one of claims 1 to 3 are fully mixed; reacted at 35° C.-40° C., cooled after the reaction, washed and dried to obtain the product.
5. The preparation method according to claim 4, characterized in that: The reaction time is 1h-4h; And / or, washing is performed by using ethanol and / or water for multiple times.
6. Use of the metal organic framework material with a dual ligand strategy as described in any one of claims 1 to 3 or the metal organic framework material prepared by the preparation method as described in claim 4 or 5 in the detection of DPA.
7. A ratiometric fluorescent probe, characterized in that The invention comprises the metal organic framework material with dual ligands as described in any one of claims 1 to 3 or the metal organic framework material prepared by the preparation method as described in claim 4 or 5.
8. The ratiometric fluorescent probe according to claim 7, characterized in that: The mass concentration of the metal organic framework material is 0.001-0.006 mg / mL.
9. Use of the ratiometric fluorescent probe according to claim 7 or 8 for quantitative detection of DPA.
10. The use according to claim 9, characterized in that: The concentration of DPA can be quantitatively calculated from the ratio of the fluorescence intensity at the emission peaks at 621 nm and 450 nm.