Nano-porous PEEK / ZIF-8 material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of surface modification of biological materials, and particularly discloses a nano-porous PEEK / ZIF-8 material as well as a preparation method and application thereof. According to the preparation method, sulfonation treatment and plasma treatment are carried out on a polyether-ether-ketone sheet, a bionic nano-porous fiber network structure is formed on the surface of the polyether-ether-ketone sheet, on the basis, ZIF-8 nano-particles grow in situ, and meanwhile, the original nano-porous network structure is reserved; through the construction of a bionic nano porous fiber network structure and the in-situ growth of ZIF-8, the oxidation resistance of the material is synergistically enhanced, and the in-situ growth ZIF-8 can also endow the nano structure with certain drug delivery ability, so that the nano structure and the drug release coating synergistically repair bone defects under special pathological conditions.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of implant surface modification, and relates to a nano-porous PEEK / ZIF-8 material and a preparation method and application thereof. BACKGROUND

[0002] Under the pathological condition of osteoporosis, aging or abnormal hormone levels can cause excessive increase of ROS, leading to cell oxidative stress damage, forming a persistent inflammatory microenvironment, and further destroying bone immune balance and osteogenesis function. The destruction of bone immune balance will further exacerbate chronic inflammation, forming a vicious cycle. At present, constructing a functionally integrated surface is a feasible strategy to break through the difficulty of bone defect repair under complex pathological microenvironment conditions. Traditional strategies often release the function by loading multiple drugs and functional molecules on the surface of implants. However, such methods have the shortcomings of mutual interference between functional molecules and uncontrollable drug release kinetics. Therefore, it is essential to develop bone repair materials that can effectively regulate this complex pathological microenvironment.

[0003] Among the commonly used bone repair materials at present, polyether ether ketone (PEEK) is widely used in bone defect repair due to its equivalent elastic modulus to human cortical bone, excellent biocompatibility, good chemical stability and radio-transparency. However, PEEK is limited in biological applications due to its chemical inertness. Common modification methods such as sulfonation treatment have poor morphology adjustability and are difficult to meet the needs of multifunctional design under complex pathological conditions (such as osteoporosis).

[0004] ZIF-8 has the characteristics of large porosity, large specific surface area, good biocompatibility, and drug protection. Moreover, ZIF-8 can achieve controlled drug release under a slightly acidic physiological environment by utilizing its acidolysis ability, and is widely used as a carrier for many drugs. At present, some studies have introduced ZIF-8 as a drug carrier into the surface of PEEK implants, such as relying on a polydopamine (PDA) coating as an intermediate layer to fix drug-loaded ZIF-8 particles. However, this strategy often covers the nano-morphology features of the substrate surface, and usually only plays the role of drugs, failing to play the important role of nano-structure in the process of osteoporotic bone defect repair. SUMMARY

[0005] The application provides a preparation method of a nanoporous PEEK / ZIF-8 material, wherein a washed and polished polyether ether ketone is used as a substrate, a nanoporous network fiber structure is obtained through sulfonation treatment and plasma treatment, zinc ions are adsorbed to the surface of the network fiber through the polar group adsorption of the polyether ether ketone substrate after the sulfonation treatment and the plasma treatment, then the DSPEEK adsorbing the zinc ions is soaked in a 2-methyl imidazole methanol solution for in-situ growth of ZIF-8 particles through coordination combination between the zinc ions and the 2-methyl imidazole. The network fiber is used as a growth substrate of the ZIF-8, the zinc ions adsorbed to the surface of the fiber are used as growth sites, and finally the ZIF-8 particles are grown on the network fiber. The ZIF-8 particles prepared by the method are in-situ grown on the nanofiber column and are tightly combined with the fiber, and meanwhile the nanotopography characteristics of the surface of the polyether ether ketone matrix are retained. The large specific surface area of the ZIF-8 particles and the pH response release are used to achieve intelligent controllable release of drugs.

[0006] The application is realized through the following technical scheme and four steps. 1) Sulfonation treatment of polyether ether ketone (SPEEK): The polyether ether ketone sheet is sequentially cleaned by ultrasonic cleaning in acetone, ethanol and deionized water and is polished smooth by sandpaper with different mesh sizes. A 12-hole plate is taken and 2ml of 98% concentrated sulfuric acid is added to each hole, the polyether ether ketone sheet is placed in the sulfuric acid with the front face downward for sulfonation treatment, the treatment time is 30s, after the sulfonation is completed, the polyether ether ketone sheet is taken out, cleaned in deionized water and dried to obtain a microporous structure.

[0007] Preferably, the thickness of the polyether ether ketone sheet is 2mm.

[0008] 2) Plasma treatment of sulfonated polyether ether ketone (DSPEEK): The speek prepared in step 1) is placed in a plasma cleaning machine (PT-5S), the power is adjusted to 120W, the machine treatment time is 20min, after the treatment is completed, the plasma cleaning agent cavity door is opened, and the sample is taken out when the cavity is cooled to room temperature.

[0009] Preferably, the plasma treatment gas is pure oxygen.

[0010] 3) Zinc ion adsorption (DSPEEK / Zn 2+ ): The dspeek prepared in step 2) is soaked in a zinc nitrate hexahydrate solution, is taken out after standing, is washed with clean water and is dried in an oven. A nanoporous network fiber structure with zinc ion adsorption is obtained.

[0011] Preferably, the concentration of the zinc nitrate hexahydrate solution is 50-400mmol / L.

[0012] More preferably, the concentration of the zinc nitrate hexahydrate solution is 50 mmol / L.

[0013] Preferably, the settling time is 1-12 hours.

[0014] More preferably, the settling time is 6 hours.

[0015] 4) In-situ growth of ZIF-8 particles (DSPEEK / ZIF-8): The DSPEEK / Zn prepared in step 3) 2+ The material was immersed in 2-methylimidazole solution, left to stand for 12 hours, then removed, rinsed with water, and dried in an oven to obtain a ZIF-8 coating grown in situ on the surface of the nanoporous network fiber, thus preparing the nanoporous PEEK / ZIF-8 material.

[0016] Preferably, the molar concentration of the 2-methylimidazole solution is 1-100 mmol / L.

[0017] More preferably, the molar concentration of the 2-methylimidazole solution is 50 mmol / L.

[0018] Preferably, the settling time is 1-12 hours.

[0019] More preferably, the settling time is 6 hours.

[0020] Furthermore, the nanoporous PEEK / ZIF-8 material prepared by the above method.

[0021] Furthermore, the nanoporous PEEK / ZIF-8 material is used in bone defect repair and as a drug sustained-release carrier.

[0022] The application develops a nanostructure which can endow PEEK material surface with anti-cell oxidative ability without introducing antioxidants, and endows PEEK material with the application of bone regeneration and repair under special pathological conditions such as osteoporosis and diabetic pathological microenvironment. Specifically, we use sulfonation, plasma treatment and in-situ growth of ZIF-8 nanoparticles to construct a nano-scale porous fiber network structure on the surface of PEEK, and the growth of ZIF-8 can endow the nano-fiber surface with finer secondary nano-point structure, and the anti-oxidation ability of the nanostructure is proved by experiments. First, the micron-scale porous network structure is treated by sulfonation in the PEEK material, then the micron porous network is nano-remodeled by plasma treatment to prepare PEEK material with nano-fiber network structure, and finally the in-situ growth of ZIF-8 on the surface of the nano-fiber endows the nano-fiber with smaller secondary nano-point structure, and further enhances the anti-oxidation ability of the nanostructure. In addition, the in-situ growth of ZIF-8 can also endow the nanostructure with certain drug application ability, so that its application potential in bone defect repair under complex pathological conditions is wider, and it has the application potential of the synergistic effect of combining nanostructure and drugs.

[0023] The beneficial effects of the application are: I) Constructing a nano-porous network fiber structure on the surface of polyether ether ketone, improving the surface hydrophilicity and hydrophobicity and surface roughness, improving the surface biocompatibility, effectively improving the ROS removal under inflammatory microenvironment, and improving the anti-oxidative stress performance.

[0024] II) By introducing polar groups on the surface of polyether ether ketone through plasma treatment technology, Zn 2+ is adsorbed to the surface of the nano-fiber, and the release of the ion will enhance the bioactivity of polyether ether ketone.

[0025] III) The ZIF-8 particles prepared by the method are “grown” on the nano-porous network fiber, instead of being synthesized and then stacked and covered on the surface of the nanostructure as in the traditional method, forming the synergistic effect of the nanostructure and ZIF-8 drug release promotion. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 SEM images of the surface of DSPEEK / ZIF-8 of Examples 1-4: A is Example 1; B is Example 2, C is Example 3, D is Example 4; Figure 2 SEM images of the surface of PEEK, SPEEK and DSPEEKk in Example 1; Figure 3 Energy spectrum scanning diagram of DSPEEK / ZIF-8 in Example 1; Figure 4 FTIR spectrum of DSPEEK / ZIF-8 in Example 1; Figure 5 Figure for PEEK, SPEEK, DSPEEK and DSPEEK / ZIF-8 in Example 1, Example 2, Example 3, Example 4 in Example 1, Example 2, Example 3, Example 4 of anti-oxidative stress performance graph; Figure 6 Figure for PEEK, SPEEK, DSPEEK and DSPEEK / ZIF-8 in Example 1, Example 2, Example 3, Example 4 in Example 1 of cell proliferation graph; Figure 7 Figure for PEEK, SPEEK, DSPEEK and DSPEEK / ZIF-8 in Example 1, Example 2, Example 3, Example 4 in Example 1 of ALP staining graph; Figure 8 Figure for PEEK, SPEEK, DSPEEK and DSPEEK / ZIF-8 in Example 1, Example 2, Example 3, Example 4 in Example 1 of ALP quantitative graph; Figure 9 Figure for PEEK, SPEEK, DSPEEK and DSPEEK / ZIF-8 in Example 1 of surface SEM graph. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be further illustrated by specific embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present application and should not be regarded as specific limitations of the present application.

[0028] Example 1

[0029] (1) Preparation of polyether ether ketone microporous structure by sulfonation treatment

[0030] The polyether ether ketone disc substrate used this time is 10mm x 10mm x 0.2mm (Jiangsu Junhua Special Polymer Materials, PEEK5600G). The polyether ether ketone sheet was placed in a beaker, and acetone, ethanol and deionized water were added in turn and ultrasonically cleaned for 10min, and deionized water was ultrasonically cleaned three times. The polyether ether ketone was distinguished by scratching the front and back. The polyether ether ketone substrate was polished by a polishing machine, and the back of the polyether ether ketone disc was fixed on the finger with double-sided tape and pressed for polishing. Different grit sandpaper (2000, 3000, 4000) was replaced on the polishing machine in turn, and after polishing, it was placed in an oven for drying, and PEEK was obtained.

[0031] Prepare a 12-well plate, and in each well, use a pipette to remove 2ml of 98% concentrated sulfuric acid. The front of the polyether ether ketone disc is downward, and the disc is immersed in the sulfuric acid solution with tweezers. Sulfonate for 30s, quickly clamp out and place in a beaker containing deionized water. When the sulfonation reaction is completely terminated, take it out and place it in another beaker containing deionized water for ultrasonic cleaning. Oven drying, SPEEK was obtained.

[0032] (2) Preparation of nanostructure by plasma treatment of sulfonated polyether ether ketone

[0033] The plasma power is adjusted to 120W, the plasma treatment time is adjusted to 20min, the plasma treatment gas is selected to be oxygen, the plasma machine is preheated first, after the preheating is completed, the sulfonated polyether ether ketone disc is laid flat on the corundum surface with the front surface facing upward, the chamber door is closed after the plasma treatment is completed, the chamber door is opened after the chamber temperature is reduced to room temperature, and the sample is taken out, and the DSPEEK is obtained.

[0034] (3) Zinc ion adsorption

[0035] A 50mmol / L Zn(NO)3·6H2O methanol solution is configured, the polyether ether ketone with a nano-porous network fiber structure prepared in the second step is placed in a 30ml glass bottle with the front surface facing upward, 10ml of the configured 50mmol / L Zn(NO)3·6H2O methanol solution is added, and the reaction is allowed to stand at room temperature for 6h, so that the Zn 2+ ions are adsorbed on the surface of the nano structure. After 6h, the polyether ether ketone matrix is cleaned with deionized water to remove the excess zinc ion solution attached to the surface, and a nano-porous network fiber structure polyether ether ketone matrix containing Zn 2+ adsorbed is obtained, which is denoted as DSPEEK / Zn 2+ .

[0036] (4) In-situ growth of ZIF-8 on the surface of the polyether ether ketone nano fiber structure

[0037] An organic ligand 2-methyl imidazole (2-MIM) methanol solution required for the growth of ZIF-8 is configured, and the molar concentration of the 2-methyl imidazole is 50mmol / L methanol solution. The sample DSPEEK / Zn 2+ prepared in the third step is placed in a 30ml glass bottle with the front surface facing upward, the lid is covered, then 10ml of the 2-methyl imidazole (2-MIM) methanol solution is slowly added, and the ZIF-8 is allowed to grow in-situ at room temperature for 6h. After 6h, the polyether ether ketone matrix is cleaned with deionized water to remove the excess ZIF-8 particles attached to the surface, and the sample obtained after drying is the polyether ether ketone on which the ZIF-8 is grown in-situ on the surface of the nano-porous network fiber (DSPEEK / ZIF-8).

[0038] The morphology chart results are shown in Figure 1 、 2 , Figure 2 A is the PEEK surface morphology chart, and the surface has obvious scratches; Figure 2 B is the PEEK after sulfonation, and a multi-level micron-level pore structure is presented; Figure 2 C is the plasma treated sulfonated PEEK, and the surface morphology has a nano-level porous network fiber structure remodeled from the original microporous structure. Figure 1A is the morphology of ZIF-8 grown in-situ on the surface of the plasma-treated sulfonated PEEK, and the ZIF-8 particles are uniformly distributed on the surface of the network fibers.

[0039] Example 2

[0040] (1) Sulfonated PEEK treated by plasma, same as Example 1; (2) Plasma-treated sulfonated PEEK, same as Example 1; (3) Zn 2+ ion adsorption, same as Example 1; (4) In the process of growing ZIF-8 particles in-situ on the surface of the PEEK nanofiber structure, the molar concentration of 2-methylimidazole solution is changed from 50 mM to 400 mM, and other parameters and steps are the same as Example 1. 2+ (4) In the process of growing ZIF-8 particles in-situ on the surface of the PEEK nanofiber structure, the molar concentration of 2-methylimidazole solution is changed from 50 mM to 400 mM, and other parameters and steps are the same as Example 1.

[0041] The results are shown in Figure 1 B, the method prepared ZIF-8 particles are numerous, dense distribution on the surface of the nanofiber, part of the shielding nanostructure.

[0042] Example 3

[0043] (1) Sulfonated PEEK treated by plasma, same as Example 1; (2) Plasma-treated sulfonated PEEK, same as Example 1; (3) Zn 2+ ion adsorption, same as Example 1; (4) In the process of growing ZIF-8 particles in-situ on the surface of the PEEK nanofiber structure, the molar concentration of 2-methylimidazole solution is changed from 50 mM to 400 mM, and other parameters and steps are the same as Example 1.

[0044] The results are shown in Figure 1 C, the method prepared ZIF-8 particles are smaller, mostly round dense accumulation of small balls.

[0045] Example 4

[0046] (1) Sulfonated PEEK treated by plasma, same as Example 1; (2) Plasma-treated sulfonated PEEK, same as Example 1; (3) Zn 2+ ion adsorption, same as Example 1; (4) In the process of growing ZIF-8 particles in-situ on the surface of the PEEK nanofiber structure, the molar concentration of 2-methylimidazole solution is changed from 50 mM to 400 mM, and other parameters and steps are the same as Example 1.

[0047] The results are shown in Figure 1As shown in FIG. D, after the ZIF-8 grew on the surface of the fiber, the fiber was ultrasonically cleaned, the ZIF-8 particles on the surface of the fiber fell off, and only a small part of the particles were adsorbed on the surface of the nanofiber.

[0048] Comparative Example 1

[0049] Pure ZIF-8 synthesis: 10 ml of 50 mmol / L Zn(NO)3·6H2O solution was prepared in a beaker, and 10 ml of 50 mmol / L 2-methylimidazole solution was prepared in a beaker, the solvent was methanol, and the rotor was stirred for 6H. After the reaction, the suspension was centrifuged at 10,000 rpm for 10 min to remove the supernatant, and the white precipitate was collected, redispersed with methanol and centrifuged, and repeated twice to remove excess residues. The white precipitate was dried in a 50°C oven overnight, and after grinding, ZIF-8 particle powder was obtained.

[0050] Material characterization and performance testing

[0051] (1) Morphology observation of the sample: After the sample was sprayed with gold, the surface morphology of the substrate was observed by field emission scanning electron microscopy, and the surface morphology was as shown in FIG. 2. Figure 1 and Figure 2 FIGS. 3, 4, 5 and 6 show the surface morphology of PEEK, SPEEK, DSPEEK and DSPEEK / ZIF-8 in Example 1, Example 2, Example 3 and Example 4, respectively.

[0052] (2) Energy dispersive X-ray spectroscopy-mapping (EDS-mapping) test: The DSPEEK / ZIF-8 sample of Example 1 was scanned and tested by an X-ray energy spectrometer, and the element distribution map was as shown in FIG. 7. Figure 3 As shown in FIG. 7, Zn, N and O elements were detected, and they showed a highly consistent spatial distribution in the entire selected crystal region, verifying that the nanoparticles grown in situ on the surface of the ion-treated sulfonated polyether ether ketone were ZIF-8 nanoparticles.

[0053] (3) Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR) test: The DSPEEK / ZIF-8 sample of Example 1 was subjected to ATR-FTIR test by a Fourier infrared transform spectrometer, and the infrared spectrum was as shown in FIG. 8. Figure 4 As shown in FIG. 8, the S=O symmetric stretching vibration peaks at 1015 cm -1 and 1080 cm -1 and the O=S=O asymmetric stretching vibration peak at 1250 cm -1 indicated that the sulfonation treatment introduced sulfonic acid groups on the surface of PEEK, and the 1015 cm -1 and 1090 cm -1Weak peaks at S=O are due to the elimination of sulfonic acid groups by plasma treatment etching and reshaping, 1585 cm -1 and 1420 cm -1 correspond to the characteristic peaks C=N, C-N of ZIF-8, respectively. This further indicates that the ZIF-8 particles are in-situ grown on the surface of the plasma-treated sulfonated polyether ether ketone nanoparticles.

[0054] (4) Anti-oxidative stress experiment of the samples: The PEEK, SPEEK, DSPEEK, DSPEEK / ZIF-8 in Example 1, the DSPEEK / ZIF-8 in Example 2, Example 3, Example 4 and the ZIF-8 in Comparative Example 1 were placed in a 24-well plate after sterilization, and MC3T3-E1 cells were inoculated on the samples at a density of 4x10 4 cells / well, and cultured in an incubator at 37°C for 24h, 500μl of 1.5mM hydrogen peroxide was added to each well for 1h of stimulation, the cells were washed with PBS solution for 3 times, 500μl of DCFH-DA / Hoechst culture medium mixed solution (DCFH-DA, Hoechst and serum-free a-MEM culture medium were mixed at a ratio of 1:2:1000) was added to each well for 30min of incubation, and Leica point scanning confocal was used for imaging. It can be seen from Figure 5 that the nano-network structure formed after plasma treatment is beneficial to the anti-oxidative stress performance, ZIF-8 alone has no anti-oxidative stress performance, and the in-situ growth of ZIF-8 on this basis continues to improve the anti-oxidative stress performance, among which the sample dspeek / ZIF-8 in Example 1 has the best anti-oxidative stress performance.

[0055] (5) Cell proliferation experiment of the samples: The PEEK, SPEEK, DSPEEK, DSPEEK / ZIF-8 in Example 1 were placed in a 24-well plate after sterilization, MC3T3-E1 cells were inoculated on the samples at a density of 2x10 4 cells / well, and cultured in an incubator at 37°C, and the proliferation of the samples was tested by CCK-8 at 3d and 7d after inoculation of the material, the original culture solution was removed, 400μl of CCK-8 culture medium was added to each well, and then incubated in an incubator for 2h, the co-culture solution of CCK-8 and the sample was collected and transferred to a 96-well plate, and the absorbance was measured by an enzyme marker at 450nm. It can be seen from Figure 6 that compared with the PEEK, SPEEK, DSPEEK samples, the DSPEEK / ZIF-8 in Example 1 has good bioactivity and can promote cell proliferation, which is attributed to the controlled release of Zn 2+ and the effect of nanostructure.

[0056] (6) ALP osteogenic performance experiment of the sample: After sterilization, the PEEK, SPEEK, DSPEEK and DSPEEK / ZIF-8 in Example 1 were placed in a 24-well plate, and MC3T3-E1 cells were inoculated on the samples at a density of 2x10 4 ALP staining: the culture solution was discarded, and the cells were fixed with 4% paraformaldehyde (PFA) solution at room temperature for 20 min. After fixation, the residual fixative was washed away with PBS solution, 1 ml of BCIP / NBT staining working solution was added to each sample, and the sample was incubated in the dark for 30 min. ALP quantitative determination: the cells were incubated with p-nitrophenyl phosphate at 37 °C for 30 min. Then the ALP activity was obtained by measuring OD405. Finally, the cell ALP level was obtained by normalization according to the total protein content measured by the BCA protein detection kit. From Figure 7 and Figure 8 It can be seen from the staining and quantitative results that, compared with PEEK, SPEEK and DSPEEK, the sample DSPEEK / ZIF-8 has the largest APL positive area on the surface and the best staining effect. The ALP quantitative results are similar to the qualitative results, indicating that the in-situ growth of ZIF-8 particles on the surface of the nano-porous fiber structure is conducive to ALP expression and promotes osteogenesis.

[0057] Based on the above ideal embodiments according to the present application, through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the contents of the specification, and must be determined according to the scope of the claims.

Claims

1. A method for preparing a nanoporous PEEK / ZIF-8 material, characterized in that, Includes the following steps: (1) Surface pretreatment of polyetheretherketone (PEEK) sheets; (2) Sulfonation treatment to obtain SPEEK; (3) Plasma treatment to obtain DSPEEK; (4) ZIF-8 was grown in situ to obtain nanoporous PEEK / ZIF-8 material.

2. The method for preparing nanoporous PEEK / ZIF-8 material as described in claim 1, characterized in that, The pretreatment in step (1) includes cleaning and smoothing. The specific steps are as follows: the polyetheretherketone sheet is placed in acetone, ethanol and deionized water in sequence for ultrasonic cleaning and then polished with sandpaper; the thickness of the polyetheretherketone sheet is 2mm.

3. The method for preparing the nanoporous PEEK / ZIF-8 material as described in claim 1, characterized in that, The specific steps of the sulfonation treatment are as follows: immerse the polyether ether ketone (PEEK) sheet face down in concentrated sulfuric acid for 30 seconds, then remove, clean, and dry.

4. The method for preparing the nanoporous PEEK / ZIF-8 material as described in claim 1, characterized in that, The plasma treatment has a power of 120W, a treatment time of 20 minutes, and uses pure oxygen as the treatment gas.

5. The method for preparing the nanoporous PEEK / ZIF-8 material as described in claim 1, characterized in that, The specific steps for the in-situ growth of ZIF-8 are as follows: immerse the DSPEEK obtained in step (2) in zinc nitrate hexahydrate solution, let it stand, clean it, and dry it, then immerse it in 2-methylimidazole solution, let it stand, clean it, and dry it.

6. The method for preparing the nanoporous PEEK / ZIF-8 material as described in claim 5, characterized in that, Place Narrative The concentration of zinc nitrate hexahydrate solution is 50-400 mmol / L.

7. The method for preparing the nanoporous PEEK / ZIF-8 material as described in claim 5, characterized in that, Place Narrative The concentration of 2-methylimidazole solution is 1-100 mmol / L.

8. The method for preparing the nanoporous PEEK / ZIF-8 material as described in claim 5, characterized in that, The settling time is 1-12 hours.

9. A nanoporous PEEK / ZIF-8 material prepared by the method according to any one of claims 1-8.

10. The application of the nanoporous PEEK / ZIF-8 material as described in claim 9 in bone defect repair and drug sustained-release carrier.

Images