CN104759242B - A kind of method utilizing yeast synthesis metallic organic framework hollow structure capsule - Google Patents

Abstract

The invention discloses a kind of method utilizing yeast synthesis metallic organic framework hollow structure capsule, described method is: slaine or organic ligand are made an addition in cell wall suspension, 50 140 DEG C of stirring 6 24h, it is thus achieved that the cell wall containing metal ion or the cell wall containing organic ligand；Being scattered in organic ligand saline solution by cell wall containing metal ion, or be scattered in metal salt solution by the cell wall containing organic ligand, 50 140 DEG C are slowly stirred crystallization, i.e. obtain metallic organic framework cell wall capsule；The structure of the metallic organic framework cell wall capsule synthesized by the present invention can be controlled according to the condition of synthesis and process, a size of tens nanometer is to hundreds of nanometers, can be to be grown in cell wall inner surface and outer surface by controlling to soak the sequential control metallic organic framework layer of part and metal salt solution, the metallic organic framework cell wall capsule of synthesis has good solvent resistance and good mechanical strength.

Description

A method for synthesizing metal-organic framework hollow structure capsules by using yeast

(1) Technical field

The invention relates to the preparation of a metal-organic framework, in particular to a method for synthesizing a metal-organic framework-cell wall capsule by using yeast as a support.

(2) Background technology

Capsules generally refer to semi-permeable spherical solids with a hollow interior. It can usually be used in encapsulation, catalysis, microreactors, detectors, drug sustained release, etc. At the same time, the semipermeability of the capsule can be adjusted by changing the characteristics of the capsule wall. However, the traditional synthesis methods of capsules usually encounter problems such as low efficiency, difficulty in scaling up, and poor controllability. These problems limit the research and development of capsules to a large extent. The materials for preparing capsules are also various. Such as polymers, molecular sieves, metal organic compounds, etc. can be used in the preparation of capsules. As a kind of coordination compound, metal organic framework material is composed of metal nodes and organic ligands through coordination bonds. It has good chemical stability and thermal stability, and also has the following characteristics: huge specific surface area, Microporous or mesopore-level pore structure, diversity of chemical modification, gas selective adsorption, etc. Therefore, it is widely used in adsorption/separation, catalysis, detector, drug sustained release, fuel cell ion membrane and so on.

Metal-organic frameworks have also been used in the preparation of capsules in recent years. De Vos et al. obtained Cu-BTC (a metal-organic framework) capsule by interfacial synthesis, and proved that the capsule has selective permeability. Maspoch et al. synthesized a series of metal-organic framework capsules by spray-drying method and applied them in encapsulation and catalysis. Wang et al. synthesized nanoscale MOF capsules by adding povidone to the synthesis solution. These capsules are however unsupported. Due to the poor flexibility of MOFs and not very stable mechanical properties, unsupported MOF capsules may be disadvantageous in terms of sustained use.

Most metal-organic framework membranes are obtained by growing metal-organic frameworks on the base membrane. Therefore, if the metal-organic framework can be grown on the hollow spherical substrate, a supported metal-organic framework capsule can be obtained, and the stability of the capsule can be improved. At the same time, according to the preparation conditions of the metal-organic framework membrane, it can be seen that the hollow spherical substrate should have the following characteristics: 1) The substrate should have good mechanical stability. 2) The substrate should be permeable. 3) The substrate should have a large number of heterogeneous nucleation sites. Yeast cell wall, as a natural hollow material, can perfectly meet the above characteristics. As the outermost protective structure of cells, it has excellent mechanical and chemical stability. At the same time, the cell wall is almost completely permeable. Furthermore, as a structure composed of organic biomacromolecules, it has a large number of polar groups, so it can adsorb ligands or metal ions of metal-organic bone precursors to form heterogeneous crystal nuclei when synthesizing organometallic framework capsules. In this way, if the cell wall is used for the preparation of the metal-organic framework capsule, its application range will be greatly improved.

(3) Contents of the invention

The object of the present invention is to provide a method for preparing metal organic framework capsules, which is a method for synthesizing metal organic framework-cell wall capsules by using yeast cell walls as supporting substrates.

The technical scheme adopted in the present invention is:

The invention provides a method for synthesizing metal-organic framework hollow structure capsules by using yeast. The method is as follows: (1) taking yeast cell walls and suspending them in a solvent to make a cell wall suspension; then adding metal salts or organic ligands to the cell walls In the suspension, stir at 50-140°C for 6-24h (preferably 50-100°C for 12h), centrifuge, and take the precipitate to obtain cell walls containing metal ions or cell walls containing organic ligands; the solvent is water or an organic solvent; (2) Disperse the cell wall containing metal ions in an organic ligand salt solution, or disperse the cell wall containing an organic ligand in a metal salt solution, slowly stir and crystallize at 50-140°C (preferably 50-100°C), and crystallize The final suspension is cooled at room temperature, centrifuged (preferably centrifuged at 5000 rpm for 5min), removes the supernatant, and collects the precipitate to obtain metal organic framework-cell wall capsules; for different types of metal organic framework capsules The preparation of metal ions, organic ligands and solvents used are different; when the cell wall containing metal ions is dispersed in the organic ligand salt solution, the synthesized metal-organic framework layer grows on the outer surface of the cell wall; when containing organic When the liganded cell wall is dispersed in a metal salt solution, the synthesized metal-organic framework layer grows on the inner surface of the cell wall.

Further, the yeast cell wall in step (1) is from brewer's yeast or baker's yeast.

Further, the solvent in step (1) is one of the following: water, methanol, ethanol, ethylene glycol, glycerol, pyrrolidone, nitrogen nitrogen dimethylformamide, N,N-dimethylacetamide, N,N- Diethylformamide, pyridine, piperidine, furan, tetrahydrofuran, dioxane, or dimethylsulfoxide.

Further, the metal salt in step (1) is a transition metal salt, preferably Zn(NO ₃ ) ₂ ·6H ₂ O, Cu(NO ₃ ) ₂ ·3H ₂ O and FeCl ₃ ·3H ₂ O, and the organic ligand salt is Carboxylic acid ligand or imidazole ligand, the final concentration of organic ligand salt in the cell suspension is 20-400mmol/L, preferably 50-100mmol/L, and the final concentration of metal salt is 20-400mmol/L, preferably 50-100mmol /L.

Further, in step (2), the concentration of the organic ligand salt solution is 20-400mmol/L, preferably 50-100mmol/L, and the concentration of the metal salt solution is 20-400mmol/L, preferably 50-100mmol/L.

In addition, the present invention also provides a method for synthesizing metal-organic framework hollow structure capsules by using yeast. The method is as follows: disperse the yeast cell wall in the mixed solution prepared by metal salt and organic ligand solvent, and stir at 20-100°C 6-24h (preferably stirred at 50-100°C for 12h), crystallize, cool the crystallized suspension at room temperature, centrifuge at 5000 rpm for 5min, remove the supernatant, collect the precipitate, and obtain a metal-organic framework - Cell wall capsules; for the preparation of different types of metal-organic framework capsules, the metal ions and organic ligands used and the solvents used are different. The metal organic framework layer prepared by the method grows on the outer surface of the cell wall.

Further, the final concentration of the metal salt in the mixed solution is 20-400mmol/L, preferably 50-100mmol/L, most preferably 100mmol/L, and the final concentration of the organic ligand is 20-400mmol/L, preferably 50-100mmol/L, Most preferably 100mmol/L.

Further, the yeast cells are from brewer's yeast or baker's yeast.

Further, the solvent is one of the following: water, methanol, ethanol, ethylene glycol, glycerol, pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, N,N- Diethylformamide, pyridine, piperidine, furan, tetrahydrofuran, dioxane or dimethylsulfoxide.

Further, the metal salt is a transition metal salt, preferably Zn(NO ₃ ) ₂ ·6H ₂ O, FeCl ₃ ·6H ₂ O or Cu(NO ₃ ) ₂ ·6H ₂ O, and the organic ligand salt is a carboxylic acid ligand or imidazole ligands.

The metal-organic framework series described in the present invention are: CuBTC (HKUST) series, ZIF series, IRMOF series, MIL series, PCN series, FMOF series or BIO-MOF series.

The preparation method of the yeast cell wall of the present invention is as follows: take yeast powder (purchased from Angel Yeast Co., Ltd.) and disperse it in deionized water, stir and clean it, centrifuge, take the bacterial cell precipitate and disperse it in anhydrous methanol, stir and mix evenly, centrifuge, The pellet was dried at 50°C to obtain yeast cell walls.

Compared with prior art, the advantages of the present invention:

1. The cell wall of yeast has a natural hollow structure, and the cell wall is permeable, so it has a good potential for capsule synthesis.

2. The structure of the synthesized MOF-cell wall capsule can be controlled according to the synthesis conditions and process.

3. The synthesized metal-organic framework-cell wall capsule is ultra-thin, ranging from tens of nanometers to hundreds of nanometers, which can greatly benefit the application of the capsule.

4. It is possible to control whether the metal-organic framework layer grows on the inner surface and the outer surface of the cell wall by controlling the order of soaking the ligand and the metal salt solution.

5. The synthesized metal-organic framework-cell wall capsule has good solvent resistance and good mechanical strength.

(4) Description of drawings

Fig. 1 is a scanning electron microscope (A) and a microscope image (B) of the ZIF-8-yeast cell wall capsule synthesized in Example 1 of the present invention.

Fig. 2 is a micrograph of the MIL-53-yeast cell wall capsule synthesized in Example 2 of the present invention.

(5) Specific implementation methods

The present invention is further described below in conjunction with specific embodiment, but protection scope of the present invention is not limited thereto:

Example 1:

Synthesis of ZIF-8-Yeast Cell Wall Capsules

(1) Disperse 0.05 g of yeast powder (purchased from Angel Yeast Co., Ltd.) in deionized water, stir and wash, centrifuge and set aside.

(2) Disperse the bacterial cells obtained in step (1) in anhydrous methanol, stir and mix evenly, then centrifuge, and dry the precipitate at 50° C. to obtain yeast cell walls. The obtained cell wall was dispersed in 10 mL of anhydrous methanol to obtain a yeast cell wall suspension.

(3) Dissolve 0.5 mmol of Zn(NO ₃ ) ₂ ·6H ₂ O in 10 mL of the above yeast cell wall suspension, place it at 50°C and stir for 12 hours, so that the metal ions enter the inner cavity of the cell wall, and centrifuge to obtain Cell walls that contain metal ions.

(4) Configure 50mmol/L 2-methylimidazole methanol solution, disperse the cell wall containing metal ions in 50mmol/L 2-methylimidazole methanol solution, stir and crystallize for 12 hours at 50°C, let the crystallized The suspension was cooled at room temperature (25°C), then centrifuged at 5000 rpm for 5 minutes, the supernatant was removed, and the precipitate was collected to obtain metal-organic framework-cell wall capsules, which were dried at 60°C for use.

To test the continuity and mechanical properties of the synthesized capsules, the Zn(NO ₃ ) ₂ ·6H ₂ O yeast cell wall suspension in step (2) and the 2-methylimidazole methanol solution in step (3) were added with Rose Dye, the final concentration is 0.1g/L, so that the inside of the synthesized capsule will contain rose bengal molecules; the metal organic framework-cell wall capsules containing rose bengal molecules are washed with methanol, and placed in methanol for stirring, while detection of methanol The content of rose bengal; its content is almost zero; when hydrochloric acid is added to methanol, the solution turns red immediately, which indicates that the synthesized capsule wall is continuous. The metal-organic framework-cell wall capsules containing rose bengal molecules were washed with methanol and then placed in methanol and stirred for ultrasonication. Only 20% of rose bengal was released by ultraviolet-visible spectrometer, which indicated that the capsules had good mechanical strength and were resistant to sonicated. The obtained metal-organic framework-cell wall capsule is shown in Figure 1 . A continuous metal-organic framework can be seen growing on the surface of the yeast cell wall. The thickness of the metal skeleton is between 60-90nm.

Example 2:

Synthesis of MIL-53-Yeast Cell Wall Capsules

(1) Take 0.05g of yeast powder and disperse in deionized water, stir and wash, centrifuge and set aside.

(2) The obtained bacteria were dispersed in anhydrous methanol, stirred and centrifuged, and the precipitate was washed three times with N,N-dimethylformamide, and dried at 60° C. to obtain yeast cell walls. The obtained yeast cell walls were dispersed in 10 mL of N,N-dimethylformamide to obtain a cell wall suspension.

(3) Dissolve 0.5 mmol of FeCl ₃ ·6H ₂ O in 10 mL of the above cell wall suspension, place at 100° C. and stir for 12 hours, so that metal ions enter the inner cavity of the cell wall, and centrifuge to obtain cell walls containing metal ions.

(4) Configure 50mmol/L terephthalic acid N,N-dimethylformamide solution, disperse the cell wall containing metal ions in the solution, stir and crystallize at 100°C, let the crystallized suspension Cool at room temperature, then centrifuge at 5000 rpm for 5 min, remove the supernatant, collect the precipitate, obtain metal organic framework-cell wall capsules, and dry the capsules at 100°C for use.

The obtained MOF-cell wall capsule is shown in Figure 2. The hollow structure of the membrane can be clearly seen. Detected by the method described in Example 1, under the condition of stirring, rose bengal is hardly released, indicating that the capsule wall of synthesis is continuous; under the situation of ultrasound, only 10% of rose bengal is released, which indicates that the synthetic capsule wall It has good mechanical strength and is resistant to ultrasonic decomposition. The thickness of the synthesized capsule metal-organic framework layer is 40-60nm.

Example 3:

Synthesis of CuBTC-Yeast Cell Wall Capsules

(1) Take 0.05g of yeast powder and disperse in deionized water, stir and wash, centrifuge and set aside.

(2) The obtained bacteria were dispersed in anhydrous methanol, stirred and centrifuged, and the precipitate was washed three times with deionized water to obtain yeast cell walls, and dried at 50° C. for later use. The obtained cell wall was dispersed in deionized water to obtain a cell wall suspension.

(3) Dissolve 0.5 mmol of Cu(NO ₃ ) ₂ ·6H ₂ O in 10 mL of the above cell wall suspension, stir at 50°C for 12 hours, so that the metal ions enter the inner cavity of the cell wall, and centrifuge to obtain metal ions in the cell wall.

(4) Configure 50mmol/L trimesic acid ethanol solution, disperse the cell wall containing metal ions in the solution, stir at 50°C, crystallize, allow the crystallized suspension to cool at room temperature, and then Centrifuge at 5000 rpm for 5 min, remove the supernatant, collect the precipitate, and obtain the metal-organic framework-cell wall capsule, and dry the capsule at 60°C for use. Detected by the method described in Example 1, under the condition of stirring, rose bengal is hardly released; under the situation of ultrasound, only 15% of rose bengal is released; this shows that the synthetic capsule wall is continuous and has a good Excellent mechanical strength and is resistant to ultrasonic decomposition. The thickness of the synthesized capsule metal-organic framework layer is 70-100nm.

Example 4:

Synthesis of ZIF-8-Yeast Cell Wall Capsules

(1) Take 0.05g of yeast powder and disperse in deionized water, stir and wash, centrifuge and set aside.

(2) The obtained bacteria were dispersed in anhydrous methanol, stirred and centrifuged to obtain yeast cell walls, which were dried at 50° C. for future use. The obtained cell wall was dispersed in 10 mL of methanol to obtain a yeast cell wall suspension.

(3) Dissolve 1 mmol of 2-methylimidazole in 10 mL of the above-mentioned cell wall suspension, and stir for 12 hours at 50°C, so that 2-methylimidazole enters the inner cavity of the cell wall, and centrifuge to obtain a solution containing 2-methylimidazole. imidazole cell wall.

(4) Prepare 100mmol/L Zn(NO ₃ ) ₂ ·6H ₂ O methanol solution, disperse the cell wall containing 2-methylimidazole in Zn(NO ₃ ) ₂ ·6H ₂ O methanol solution, Stir for 12 hours to crystallize, let the crystallized suspension cool at room temperature, then centrifuge at 5000 rpm for 5 min, remove the supernatant, collect the precipitate, and obtain the metal-organic framework-cell wall capsule. The capsule is 60 °C for drying. Detected by the method described in Example 1, under the condition of stirring, rose bengal is hardly released; under the situation of ultrasound, only 12% of rose bengal is released; this shows that the synthetic capsule wall is continuous and has a good Excellent mechanical strength and is resistant to ultrasonic decomposition. The thickness of the synthesized capsule metal-organic framework layer is 100-130nm.

Example 5:

Synthesis of ZIF-8-Yeast Cell Wall Capsules

(1) Take 0.05g of yeast powder and disperse in deionized water, stir and wash, centrifuge and set aside.

(2) Disperse the obtained bacterial cells in anhydrous methanol, stir and centrifuge to obtain yeast cell walls, and dry them at 50° C. for later use.

(3) Dissolve 1 mmol of 2-methylimidazole and 1 mmol of Zn(NO ₃ ) ₂ ·6H ₂ O in 10 ml of methanol, disperse the prepared cell wall in the above methanol solution, stir and crystallize at 50°C, let The crystallized suspension was cooled at room temperature, then centrifuged at 5000 rpm for 5 min, the supernatant was removed, and the precipitate was collected to obtain metal-organic framework-cell wall capsules, which were dried at 60°C for use.

In order to check the continuity and mechanical properties of the synthesized capsule, the methanol solution in step (3) is added with rose bengal dye, and the final concentration is 0.1g/L, so that the inside of the synthesized capsule will contain rose bengal molecules; will contain rose bengal Molecular metal-organic framework-cell wall capsules were cleaned with methanol, and placed in methanol solvent for stirring, while detecting the content of rose bengal in methanol solvent; its content was almost zero; when hydrochloric acid was added to methanol solvent, the solution immediately turned red , which indicates that the synthesized capsule walls are continuous. The metal-organic framework-cell wall capsules containing rose bengal molecules were cleaned with methanol and then placed in methanol solvent for stirring and ultrasonication. Only 6% of rose bengal was released by ultraviolet-visible spectrometer, which indicated that the capsules had good mechanical strength and were Resistant to sonication. The thickness of the metal framework is between 300-500nm.

Claims (10)

1. A method utilizing yeast to synthesize metal-organic framework hollow structure capsules, characterized in that the method is: (1) getting yeast cell walls suspended in a solvent to make a cell wall suspension; then adding metal salts or organic ligands In the cell wall suspension, stir at 50-140°C for 6-24h, centrifuge, take the precipitate, and obtain the cell wall containing the metal ion or the cell wall containing the organic ligand; the solvent is water or an organic solvent; (2) the cell wall containing the metal ion Disperse the cell wall in the organic ligand solution, or disperse the cell wall containing the organic ligand in the metal salt solution, stir and crystallize at 50-140°C, cool the crystallized suspension at room temperature, centrifuge, remove the supernatant, and collect Precipitate, ie obtain metal-organic framework-cell wall capsules. 2. The method for synthesizing metal-organic framework hollow structure capsules by using yeast as claimed in claim 1, wherein the yeast cell wall in step (1) is from brewer's yeast or baker's yeast. 3. utilize the method for yeast to synthesize metal-organic framework hollow structure capsule as claimed in claim 1, it is characterized in that step (1) solvent is one of following: water, methyl alcohol, ethanol, ethylene glycol, glycerol, pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide, pyridine, piperidine, furan, tetrahydrofuran, dioxane, or dimethylsulfoxide. 4. utilize the method for yeast synthetic metal-organic framework hollow structure capsule as claimed in claim 1, it is characterized in that step (1) metal salt is transition metal salt, and described organic ligand is carboxylic acid ligand or imidazole ligand, The final concentration of the organic ligand in the cell suspension is 20-400mmol/L, and the final concentration of the metal salt is 20-400mmol/L. 5. utilize the method for yeast to synthesize metal-organic framework hollow structure capsule as claimed in claim 1, it is characterized in that step (2) organic ligand solution concentration is 20-400mmol/L, metal salt solution concentration is 20-400mmol/L . 6. A method for synthesizing metal-organic framework hollow structure capsules using yeast, characterized in that the method is: take yeast cell walls and disperse them in a mixed solution prepared from a mixture of metal salts and organic ligands with a solvent, at 20-100 Stir and crystallize at ℃, cool the crystallized suspension at room temperature, centrifuge, remove the supernatant, collect the precipitate, and obtain the metal-organic framework-cell wall capsule. 7. The method for synthesizing metal-organic framework hollow structure capsules by yeast as claimed in claim 6, characterized in that the final concentration of the metal salt in the mixed solution is 20-400mmol/L, and the final concentration of the organic ligand is 20-400mmol/L. 8. The method for synthesizing metal-organic framework hollow structure capsules by using yeast as claimed in claim 6, wherein the yeast cell wall is from brewer's yeast or baker's yeast. 9. The method for utilizing yeast to synthesize metal-organic framework hollow structure capsules as claimed in claim 6, wherein said solvent is one of the following: water, methanol, ethanol, ethylene glycol, glycerol, pyrrolidone, N, N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide, pyridine, piperidine, furan, tetrahydrofuran, dioxane, or dimethylsulfoxide. 10. The method for synthesizing metal-organic framework hollow structure capsules by using yeast as claimed in claim 6, wherein the metal salt is a transition metal salt, and the organic ligand is a carboxylic acid ligand or an imidazole ligand.