Preparation method of photoresponse COFs coated CeO2 nano-enzyme

Abstract

The invention discloses a preparation method of photoresponse COFs coated CeO2 nano-enzyme, and relates to the field of nano-materials. According to the invention, FePc, TAPP and 2, 5-dihydroxy-1, 4-phthalaldehyde are used for creating a core-shell material CeO2 (at) FePC / por-COF of photoresponse peroxidase based on COFs (Covalent Organic Frameworks), and the core-shell material CeO2 (at) FePC / por-COF is used for preparing the photoresponse peroxidase based on COFs. According to the invention, the highly ordered structural characteristic of the COFs material is utilized, so that the problem of fluorescence quenching caused by aggregation of traditional micromolecule photosensitizers (such as porphyrin, phthalocyanine and the like) in the use process is effectively solved. According to the present invention, the photoresponsive peroxidase activity is significant, and the chromogenic substrate of tetramethyl benzidine (TMB) can be effectively catalyzed; fePc is integrated into a COFs structure, so that the photoresponse activity of the COFs under near-infrared 808 nm is enhanced, and the COFs have excellent reactive oxygen species (ROS) generation capacity, and have great potential in the aspects of photodynamic therapy, antibacterial treatment, cell imaging and the like in biomedical application.

Description

Technical Field

[0001] The present invention relates to the field of nanomaterials, and specifically to a preparation method of a light-responsive covalent organic framework-coated cerium dioxide nanozyme. Background Art

[0002] Cerium oxide (CeO 2 ) has been proven to have excellent redox properties. There is a reversible Ce 3+ / Ce 4+ redox pair in its internal structure. This unique redox pair enables CeO 2 to flexibly undergo valence conversion in different redox environments, thereby exhibiting excellent electron transfer ability. CeO 2 nanozymes have been proven to have multiple enzyme activities: peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD).

[0003] Covalent organic frameworks (COFs), a new type of porous crystalline material formed by elements such as carbon, hydrogen, oxygen, and nitrogen through covalent bonds, have some unique properties, such as modular properties, high porosity, easy modification, good stability, excellent biosecurity, etc. In photodynamic therapy (PDT), photosensitive molecules can be used as monomers of COFs to improve the treatment efficiency, and at the same time, other treatment methods can be combined for synergistic treatment; by selecting and modifying the monomers of COFs, the absorption of near-infrared light can be improved to treat deep tumors. However, the application of COF-based materials in the treatment of reactive oxygen species-related diseases is still rarely reported.

[0004] The synergistic effect between the components of composite nanomaterials can effectively enhance their enzyme-like activity. The combination of porous nanomaterials and metal oxide nanoparticles can increase the specific surface area of the nanocomposite, and at the same time, it can also act as a diffusion substrate to prevent their aggregation. The organic integration of nanozymes and COFs improves the catalytic efficiency of the material and enhances the photodynamic effect. Through this integration method, the unique advantages of each component are fully utilized, achieving an improvement in material performance and having extremely high application potential in the biomedical field. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a preparation method of a CeO 2 @FePC / por-COF light-responsive peroxidase-like enzyme.

[0006] Specifically, in one aspect, the present invention provides a preparation method of a light-responsive peroxidase-like enzyme material with a core-shell structure COFs, CeO 2Post-preparation modification: TAPP, 2,5-dihydroxy-1,4-benzenedicarboxaldehyde and FePc undergo a Schiff base reaction under the action of acid in a reaction solvent to form a core-shell structure on CeO 2 and the above-mentioned light-responsive peroxidase-like material is obtained by collecting the reaction products, washing, centrifuging, drying and grinding.

[0007] Furthermore, the preparation method of the core-shell structured CeO 2 @por-COF material includes the following steps:

[0008] Dissolve cerium nitrate hexahydrate and polyvinylpyrrolidone (PVP) ultrasonically in ethylene glycol, add a small amount of water, stir at room temperature for 30 min, and heat at 160 °C for 8 h to prepare a light purple solid CeO 2 .

[0009] Furthermore, stir the above-mentioned CeO 2 with a polyethyleneimine solution at room temperature for 1 h, and centrifuge to obtain modified CeO 2 .

[0010] Furthermore, ultrasonically dissolve the above-mentioned modified CeO 2 and PVP in a mixed solution of o-dichlorobenzene and n-butanol with a volume ratio of 1:1, add TAPP and 2,5-dihydroxy-1,4-benzenedicarboxaldehyde, and react at room temperature for 4 h under the catalysis of glacial acetic acid. Subsequently, further add acetic acid and stir at room temperature for 24 h, wash and dry to obtain a dark brown solid, which is CeO 2 @por-COF.

[0011] Furthermore, the preparation method of the core-shell structured CeO 2 @FePC / por-COF material includes the following steps:

[0012] Dissolve cerium nitrate hexahydrate and polyvinylpyrrolidone (PVP) ultrasonically in ethylene glycol, add a small amount of water, stir at room temperature for 30 min, and heat at 160 °C for 8 h to prepare a light purple solid CeO 2 .

[0013] Furthermore, stir the above-mentioned CeO 2 with a polyethyleneimine solution at room temperature for 1 h, and centrifuge to obtain modified CeO 2 .

[0014] Furthermore, the above-mentioned modified CeO 2PVP was ultrasonically dissolved in a mixed solution of o-dichlorobenzene and n-butanol with a volume ratio of 1:1. FePc, TAPP, and 2,5-dihydroxy-1,4-benzenedicarboxaldehyde were added, and the reaction was carried out at room temperature for 4 h under the catalysis of glacial acetic acid. Subsequently, acetic acid was further added, and the mixture was stirred at room temperature for 24 h. After washing and drying, a dark brown solid was obtained, which was CeO 2 @FePC / por-COF.

[0015] In the present invention, a core-shell material CeO 2 @FePC / por-COF based on COFs with peroxidase-like photocatalytic activity was created using FePc, TAPP, and 2,5-dihydroxy-1,4-benzenedicarboxaldehyde. The present invention utilizes the highly ordered structural characteristics of COFs materials to effectively solve the problem of fluorescence quenching caused by aggregation during the use of traditional small molecule photosensitizers (such as porphyrins and phthalocyanines). The present invention has significant peroxidase-like photocatalytic activity and can effectively catalyze the chromogenic substrate of 3,3',5,5'-tetramethylbenzidine (TMB). By integrating FePc into the COFs structure, the present invention enhances its photocatalytic activity at 808 nm in the near-infrared region and has excellent reactive oxygen species (ROS) generation ability, which has great potential for photodynamic therapy, antibacterial therapy, and cell imaging in biomedical applications.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The present invention integrates CeO 2 for the first time, porphyrin-based COFs, and CeO 2 @FePc / por-COF optimized by FePc, and successfully constructs a nanozyme with a unique core-shell structure. This structure not only combines the excellent properties of metal oxide CeO 2 and COFs materials, but also further improves the catalytic performance by the addition of FePc. The present invention can flexibly adjust the shell thickness by finely controlling the dosage of double ligands (PEI, PVP). This characteristic can customize different shell thicknesses according to needs to meet the requirements of different application scenarios. The high porosity and easy modification of COFs materials themselves make them an ideal carrier material and can be used in biomedical and other fields. The photocatalytic nanozyme process of the present invention is simple, relatively cheap, stable, and efficient compared with single COF. The catalytic reaction conditions are mild, which is conducive to large-scale industrial production and application. Description of the Drawings

[0018] Figure 1 is the transmission electron microscope image of CeO 2 @por-COF prepared by the present invention;

[0019] Figure 2is the CeO prepared by the present invention 2 Transmission electron microscope image of CeO 2 @FePc / por-COF;

[0020] Figure 3 is the X-ray diffraction pattern of the present invention;

[0021] Figure 4 is the ultraviolet absorption pattern of the present invention;

[0022] Figure 5 is the TMB color development pattern of the present invention;

[0023] Figure 6 is the DPA dye degradation pattern of the present invention;

[0024] Figure 7 is (a) of the ESR test material of the present invention 1 O 2 and (b) O 2 .- figure; Detailed implementation manners

[0025] The following are specific embodiments of the present invention, which are used to further illustrate the composition of the present invention. Example 1

[0026] CeO 2 Preparation of @por-COF material:

[0027] Dissolve 0.5 g of cerium nitrate hexahydrate (Ce(NO 3 ) 3 6H 2 O) and 0.2 g of PVP in 15 mL of ethylene glycol by ultrasonic method, and then add 1 mL of deionized water. After continuously stirring at 250 rpm for 30 min, transfer the clear liquid to a 20 mL polytetrafluoroethylene-lined autoclave and heat it at 160 °C for 8 h. When the autoclave cools to room temperature, centrifuge at 11000 rpm for 7 min, discard the supernatant, wash the precipitate once with deionized water and twice with absolute ethanol. Finally, dry the product overnight at 60 °C, grind it and collect it. Weigh 15 mg of the above-prepared CeO 2 Disperse it ultrasonically in 2 mL of water, weigh PEI (molecular weight 25000), prepare a 100 mg / mL PEI solution with ultrapure water, and add 300 μL of the above PEI solution dropwise into the above CeO 2 solution, stir at 250 rpm at room temperature for 1 h, centrifuge at 11000 rpm for 7 min, discard the supernatant, and wash and centrifuge twice with ultrapure water. To the above PEI-modified CeO 2Add 10 mL of a solution formed by mixing o-dichlorobenzene and n-butanol in a volume ratio of 1:1, and then add 100 mg of PVP (molecular weight 30K), and ultrasonically dissolve for 0.5 h. Add 4.1 mg of 2,5-dihydroxy-1,4-benzenedicarboxaldehyde and 7.5 mg of TAPP to the above mixed solution, stir at 300 rpm for 5 min, then add 0.1 mL of glacial acetic acid to the above mixed solution, react for 4 h under stirring at 300 rpm at room temperature, add 0.3 mL of glacial acetic acid to the above mixed solution and react at room temperature for 24 h, centrifuge at 12000 rpm for 10 min, discard the supernatant and wash the precipitate three times with ethanol, and place it in a vacuum drying oven at 60 °C for drying overnight. Grind the dried sample to obtain a brown powder of CeO 2 @por-COF material.

[0028] Example 2

[0029] CeO 2 Preparation of CeO

[0030] Dissolve 0.5 g of cerium nitrate hexahydrate (Ce(NO 3 ) 3 6H 2 O) and 0.2 g of PVP in 15 mL of ethylene glycol by ultrasonic method, and then add 1 mL of deionized water. After continuously stirring at 250 rpm for 30 min, transfer the clear liquid to a polytetrafluoroethylene-lined autoclave with a capacity of 20 mL and heat at 160 °C for 8 h. When the autoclave cools to room temperature, centrifuge at 11000 rpm for 7 min, discard the supernatant, wash the precipitate once with deionized water and twice with absolute ethanol. Finally, the product is dried overnight at 60 °C, ground and collected. Weigh 15 mg of the CeO prepared above 2 Disperse it ultrasonically in 2 mL of water, weigh PEI (molecular weight 25000), prepare a 100 mg / mL PEI solution by adding ultrapure water, and add 300 μL of the above PEI solution dropwise into the above CeO 2 solution, stir at 250 rpm at room temperature for 1 h, centrifuge at 11000 rpm for 7 min, discard the supernatant, and wash and centrifuge twice with ultrapure water. To the above PEI-modified CeO 2Add 10 mL of a solution formed by mixing o-dichlorobenzene and n-butanol in a volume ratio of 1:1, and then add 100 mg of PVP (molecular weight 30K), and ultrasonically dissolve for 0.5 h. Add 4.1 mg of 2,5-dihydroxy-1,4-benzenedicarboxaldehyde, 7.5 mg of TAPP, and 5 mg of FePc to the above mixed solution. After stirring at 300 rpm for 5 min, add 0.1 mL of glacial acetic acid to the above mixed solution, and react for 4 h under stirring at 300 rpm at room temperature. Then add 0.3 mL of glacial acetic acid to the above mixed solution and react for 24 h at room temperature. Centrifuge at 12000 rpm for 10 min, discard the supernatant, wash the precipitate three times with ethanol, and place it in a vacuum drying oven at 60 °C for drying overnight. Grind the dried sample to obtain a dark brown powdery CeO 2 @FePc / por-COF material.

[0031] Example 3

[0032] CeO coated with light-responsive COFs 2 Structural characterization of nanozyme

[0033] Figure 1 For CeO 2 @por-COF transmission electron microscopy (TEM) was used to characterize the sample. The uniform solid CeO 2 nano-spheres have a size of about 50 nm, and COFs are uniformly coated on the surface of CeO 2 with a bottom thickness of about 60 nm.

[0034] Figure 2 For CeO 2 @FePc / por-COF is the TEM image. COFs are uniformly coated on the surface of CeO 2 with a bottom thickness of about 50 nm

[0035] Figure 3 This is the XRD spectrum of the nanoparticles. By comparing with the CeO2 card, it can be clearly seen that there are obvious strong diffraction peaks at 28.5°, 32.8°, 47.2°, and 56.0°, corresponding to the (111), (200), (220), and (311) crystal planes, which coincide with CeO 2 phase.

[0036] Figure 4 This is the ultraviolet absorption of the nanoparticles. Dilute the prepared CeO 2 @porphyrin-COF nanoparticles to 200 μg·mL -1 respectively. Take 4 mL of the above COF material nanoparticles into an ultraviolet cuvette, and then measure them on a UV2600 ultraviolet absorption instrument. Before measurement, perform a baseline determination with the same volume of water, and measure the absorbance of the material after subtracting the background. CeO2 @Porphyrin-COF and CeO 2 @FePc / porphyrin-COF has absorption peaks at 450 nm, 570 nm, and 660 nm, and the absorption intensity increases with the addition of FePc.

[0037] Figure 5 For the TMB oxidation test of nanoparticle-like peroxidase, dilute H 2 O 2 to 1 M, dissolve the material in DMSO to prepare a 2 mg mL -1 solution, weigh TMB and dissolve it in DMSO to prepare a 20 mg mL -1 solution. Add 100 μL of the material solution, 15 μL of the TMB solution, and 4 μL of H 2 O 2 . Use 2.3 mL of NaAC / HAC with pH = 6.5 as the buffer solution. Conduct UV tests (measure once every 2 minutes for a total of 15 minutes), with the test wavelength ranging from 550 - 750 nm, and observe its absorption peaks. After adding H 2 O 2 , the material can catalyze the oxidation reaction of TMB, turning the solution from colorless to blue. Evaluate its enzyme activity by detecting the absorption peak at 652 nm. CeO 2 @FePc / porphyrin-COF has good enzyme activity.

[0038] Figure 6 For the DPA dye degradation test of nanoparticle photo-responsive activity, weigh the material to prepare a 2 mg mL -1 solution, and the DPA dye concentration is 1 mg mL -1 . Add 100 μL of the material solution, 50 μL of the DPA dye, and 2.4 mL of buffer solution with pH 6.7 in a centrifuge tube. The total system is 2.4 mL. After pipetting evenly, place it in a UV-visible spectrophotometer. Since the characteristic absorption wavelength of DPA is 378 nm, select the test wavelength range from 300 - 450 nm. After taking it out, irradiate it with an 808 nm 1.5 W cm –2 laser for 1 minute, then put it back into the instrument for re-detection, record once every 2 minutes for 10 minutes. Under near-infrared light irradiation, the material will generate a form of reactive oxygen species - 1 O 2 . During this process, DPA will be 1 O 2 oxidized to form 1,10-phenanthrenequinone. The absorbance of the DPA dye decreases significantly with the irradiation time, indicating that CeO 2 @porphyrin-COF has good ability to generate singlet oxygen.

[0039] Figure 7 For the detection and analysis of the electron spin resonance (ESR) of nanoparticles 1 O 2 and O 2 .- Regarding the generation of, under near-infrared light irradiation, the peak intensity of CeO 2 @FePc / porphyrin-COF increased significantly, and the ability to generate 1 O 2 was significantly improved. CeO 2 @FePc / porphyrin-COF also exhibited a strong ability to generate O 2 .- .

Claims

1. A method for preparing CeO2@por-COF light-responsive nanozyme, characterized in that: The following steps are involved: (1) 0.5 g of cerium nitrate hexahydrate and 0.2 g of polyvinyl pyrrolidone (PVP) were ultrasonically dissolved in 15 mL of ethylene glycol, 1 mL of deionized water was added, stirred at room temperature for 30 min, heated at 160° C. for 8 h, centrifuged and washed, and dried and ground to obtain cerium dioxide (CeO2); (2) 15 mg of the above CeO2 was dissolved in 2 mL of deionized water, 300 μL of a 100 mg / mL polyethyleneimine solution was added dropwise thereto, the mixture was stirred at room temperature for 1 h, and centrifuged and washed to obtain modified CeO2; (3) The modified CeO2 and 100 mg PVP were ultrasonically dissolved in a mixed solution of o-dichlorobenzene and n-butanol in a volume ratio of 1:1, 7.5 mg TAPP and 4.1 mg 2,5-dihydroxy-1,4-benzenedicarbaldehyde were added and stirred for 5 min, 0.1 mL acetic acid was added, and the mixture was reacted at room temperature for 4 h, and 0.3 mL acetic acid was further added and stirred at room temperature for 24 h. The mixture was washed and dried to obtain a dark brown solid, namely CeO2@por-COF.

2. The preparation method according to claim 1, characterized in that In step (1), the constant temperature stirring speed is 250 rpm; the centrifugal condition is 11000 rpm, and the time is 7 min; the washing method is washing with deionized water once, washing with anhydrous ethanol twice, and the centrifugal condition is 11000 rpm, and the time is 7 min.

3. The preparation method according to claim 1, characterized in that In step (2), the constant temperature stirring speed is 250 rpm; the centrifugal condition is 11000 rpm, and the time is 7 min; the washing method is washing with deionized water twice, and the centrifugal condition is 11000 rpm, and the time is 7 min.

4. The preparation method according to claim 1, characterized in that In step (3), the constant temperature stirring speed is 300 rpm; the centrifugal speed is 12000 rpm, and the time is 10 min; the washing method is washing with ethanol, the number of centrifugation is 3 times, the centrifugal speed is 12000 rpm, and the time is 10 min.

5. A method for preparing CeO2@FePc / por-COF light-responsive nanozyme, characterized in that: The following steps are involved: (1) 0.5 g of cerium nitrate hexahydrate and 0.2 g of PVP were ultrasonically dissolved in 15 mL of ethylene glycol, 1 mL of deionized water was added, stirred at room temperature for 30 min, heated at 160 ° C for 8 h, centrifuged and washed, and dried and ground to obtain CeO2; (2) 15 mg of the above CeO2 was dissolved in 2 mL of deionized water, 300 μL of a 100 mg / mL polyethyleneimine solution was added dropwise thereto, the mixture was stirred at room temperature for 1 h, and the mixture was centrifuged and washed to obtain modified CeO2; (3) The modified CeO2 and 100 mg PVP were ultrasonically dissolved in a mixed solution of o-dichlorobenzene and n-butanol in a volume ratio of 1:1, 5 mg FePc, 7.5 mg TAPP and 4.1 mg 2,5-dihydroxy-1,4-benzenedicarbaldehyde were added and stirred for 5 min, 0.1 mL acetic acid was added and reacted at room temperature for 4 h, 0.3 mL acetic acid was further added and stirred at room temperature for 24 h, and a dark brown solid was obtained by washing and drying, namely CeO2@FePc / por-COF.

6. The preparation method according to claim 5, characterized in that In step (1), the constant temperature stirring speed is 250 rpm; the centrifugal condition is 11000 rpm, and the time is 7 min; the washing method is washing with deionized water once, washing with anhydrous ethanol twice, and the centrifugal condition is 11000 rpm, and the time is 7 min.

7. The preparation method according to claim 5, characterized in that In step (2), the constant temperature stirring speed is 250 rpm; the centrifugal condition is 11000 rpm, and the time is 7 min; the washing method is washing with deionized water twice, and the centrifugal condition is 11000 rpm, and the time is 7 min.

8. The preparation method according to claim 5, characterized in that In step (3), the constant temperature stirring speed is 300 rpm; the centrifugal speed is 12000 rpm, and the time is 10 min; the washing method is washing with ethanol, the number of centrifugation is 3 times, the centrifugal speed is 12000 rpm, and the time is 10 min.

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