Polycaprolactone porous scaffold capable of being degraded in vivo and efficiently promoting osteogenesis as well as preparation and application of polycaprolactone porous scaffold
The PCL porous scaffold prepared by the vapor-induced phase separation method overcomes the shortcomings of existing bone defect repair materials, achieving efficient and biodegradable bone repair, and is suitable for clinical application in extreme bone defects.
Patent Information
- Application Number
- CN202511937726.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-22
- Publication Date
- 2026-01-23
AI Technical Summary
Existing bone defect repair materials suffer from problems such as repair failure, slow osteogenic rate, improper degradation, risk of ectopic osteogenic formation, and non-degradability, especially in extreme bone defects where they fail to meet the requirements for plasticity and elasticity.
A porous polycaprolactone (PCL) scaffold was prepared using a vapor-induced phase separation method. PCL, polyethyleneimine (PEI), and cellulose (CL) were used as raw materials to form a porous structure similar to a trabecular bone network. Inorganic particles such as hydroxyapatite, β-tricalcium phosphate, calcium sulfate, or bioglass were combined to achieve the scaffold's biodegradability and osteogenic capacity.
The prepared PCL porous scaffold has excellent plasticity, elasticity, osteogenic capacity, osteoinductive and osteointegrative properties, and can efficiently repair bone defects in vivo. It also has good biocompatibility and toughness, making it suitable for the repair of extreme bone defects.
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Figure CN121371304A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the field of bone tissue engineering scaffold materials, and particularly relates to a polycaprolactone porous scaffold capable of degrading in vivo and efficiently promoting osteogenesis as well as preparation and application thereof. BACKGROUND
[0002] Rapid repair of bone defects, especially critical bone defects, is an important problem that needs to be solved in clinical practice. Artificial bone tissue engineering scaffolds are an important means to solve this problem. Compared with the gold standard of autologous bone transplantation and allogeneic bone transplantation, artificial bone scaffolds have the advantages of wide source, small rejection, avoidance of secondary surgery, etc. The most commonly used artificial bone is a phosphate material represented by hydroxyapatite (HA). This material can be obtained by synthesis, sintering or by deproteinization and decellularization of calf bone. In addition, biocompatible metal materials such as polylactic acid (PLA) and titanium alloy are also commonly used in the preparation of bone scaffolds.
[0003] Although there are many types of artificial bone materials, they still have problems such as repair failure and slow osteogenesis rate during their respective use. For example, HA particles have the risk of leakage and ectopic bone formation during use, and have poor osteoinductive ability. PLA scaffolds have the problem of slow degradation rate and degradation products affecting the osteogenic microenvironment. Although metal materials can provide good support effect, they are not degradable. In addition, there are a large number of irregular bone defects in clinical practice, such as tooth extraction socket bone defects and defects after tumor removal, which have certain requirements for the plasticity and elasticity of the scaffold material. SUMMARY
[0004] To solve the above problems, the present application aims to solve the problem of difficult repair of critical bone defects in clinical practice. A polycaprolactone (PCL) biodegradable porous osteogenic scaffold is developed using a steam-induced phase separation method. The scaffold pore structure and shape can be controlled, and the method is simple, efficient and can be scaled up. To achieve clinical application, the scaffold material consists of PCL and a small amount of cellulose. Both polymers are biocompatible and can be used as implant additives according to FDA certification. The scaffold has excellent through-hole structure, excellent plasticity, elasticity and high-efficiency osteogenic ability, as well as excellent biocompatibility, degradability, good bone integration and bone conduction, and certain toughness, making the surgical operation process simpler. The scaffold as a whole has excellent osteoinductive, osteoconductive and bone integration ability. The artificial bone preparation method disclosed in the present application is expected to solve the problem of difficult repair of bone defects in clinical practice.
[0005] Technical solutions of the present application:
[0006] In a first aspect, the present application provides a porous polycaprolactone scaffold which is degradable in vivo and highly efficient in promoting bone formation, and is formed by steam-induced phase separation using polycaprolactone (PCL), polyethyleneimine (PEI) and cellulose (CL) as raw materials.
[0007] Further, the porous polycaprolactone scaffold has a through-hole structure similar to a trabecular network and a multi-level porous structure.
[0008] Further, the mass ratio of PCL to PEI is 10:1-3:1.
[0009] As used herein, the molecular weight of PCL and PEI is generally not limited, which can be routinely selected by a person skilled in the art according to actual application and demand. As an example, the molecular weight of PCL can be 30-300,000, and the molecular weight of PEI can be 300-30,000.
[0010] Further, the mass ratio of PCL+PEI to CNF is 10:1-100:1.
[0011] Further, the CL comprises microfibrillated cellulose (MCL), bacterial cellulose (BCL), cellulose nanofiber (CNF), wherein CNF is preferred.
[0012] As used herein, the specifications of CL, such as diameter, length and -COOH content, etc. are generally not limited, which can be routinely selected by a person skilled in the art according to actual application and demand. For example, the CL is preferably CNF, the diameter of CNF is 3-100 nm, the length is 100 nm-50 μm, and the -COOH content is 0.2-3 mmol / g.
[0013] Further, the raw materials of the porous polycaprolactone scaffold can further comprise inorganic particles.
[0014] Further, the inorganic particles include hydroxyapatite, β-tricalcium phosphate, calcium sulfate or bioglass of any particle size and morphology.
[0015] Further, the mass ratio of inorganic particles to PCL is 0:1-1:1.
[0016] In a second aspect, the present application provides a method for preparing the porous polycaprolactone scaffold as described herein, which comprises the following steps:
[0017] (1) preparing a PCL / PEI precursor solution: dissolving polycaprolactone (PCL) and polyethyleneimine (PEI) in a polar organic solvent, and mixing uniformly to obtain a PCL / PEI precursor solution;
[0018] (2) preparing a CL dispersion liquid: dispersing cellulose (CL) into an organic solvent to obtain a CL dispersion liquid;
[0019] (3) steam-induced phase separation to form a scaffold: mixing the PCL / PEI precursor liquid and the CL dispersion liquid uniformly, placing the obtained mixed solution into a mold, and performing steam-induced phase separation in a sealed container containing water to precipitate a scaffold, and performing post-treatment of the scaffold to obtain a PCL porous scaffold.
[0020] Further, the concentration of the polymer in the PCL / PEI precursor liquid is 5 wt%-40 wt%, and the mass ratio of PCL to PEI is 10:1-3:1.
[0021] Further, the molecular weight of PCL is 30,000-300,000, and the molecular weight of PEI is 300-30,000.
[0022] Further, the polar organic solvent is at least one of DMF, DMSO, NMP, and DMA.
[0023] Further, the mixing includes stirring at 50-80 ℃.
[0024] Further, the PCL / PEI precursor liquid can further contain inorganic particles.
[0025] Further, the inorganic particles include hydroxyapatite, β-tricalcium phosphate, calcium sulfate, or bioglass of any particle size and morphology.
[0026] Further, the mass ratio of the inorganic particles to PCL is 0:1-1:1.
[0027] Further, in step (2), the dispersing of CL into an organic solvent includes first dispersing CL into water, and then replacing the water-dispersed CL with organic solvent-dispersed CL by using a centrifugal solvent replacement method.
[0028] Further, the concentration of CL in the water dispersion liquid is 0.2-3 wt%.
[0029] Further, the CL includes microfibrillated cellulose (MCL), bacterial cellulose (BCL), and cellulose nanofiber (CNF), and the CNF is preferred, the diameter of the CNF is 3-100 nm, the length of the CNF is 100 nm-50 μm, and the -COOH content of the CNF is 0.2-3 mmol / g.
[0030] Further, the concentration of CL in the organic solvent is 0.2-5 wt%.
[0031] Further, the organic solvent includes at least one of DMF, DMSO, NMP, and DMA.
[0032] Further, in step (3), the solid content ratio of the mixed PCL / PEI precursor solution and CL dispersion solution is 10:1-100:1.
[0033] Further, the steam-induced phase separation comprises placing the mixed solution of PCL / PEI precursor solution and CL dispersion solution in a mold, and then performing steam-induced phase separation in a sealed container containing water.
[0034] Further, the temperature of the steam-induced phase separation is 5-60 ℃, and the time is 6-48 h.
[0035] Further, the scaffold post-processing comprises removing the organic solvent, PEI and excess CL on the scaffold and drying.
[0036] Further, the scaffold post-processing comprises: after the scaffold is formed, placing the mold in water to replace the organic solvent, taking out the scaffold from the mold after the scaffold is hardened, rinsing to remove the PEI and excess CL on the scaffold, and continuing to replace the residual organic solvent with water, and finally drying to obtain the PCL porous scaffold.
[0037] Further, the water is distilled water.
[0038] In a third aspect, the present application provides a use of the in-vivo degradable and highly osteogenesis-promoting polycaprolactone porous scaffold as described herein in repairing a bone defect.
[0039] Further, the polycaprolactone porous scaffold is used as an artificial bone scaffold.
[0040] Further, the bone defect comprises a critical bone defect.
[0041] Advantages of the present application
[0042] The present application first proposes a new method for preparing a PCL porous scaffold by steam-induced phase separation of a PCL / PEI / CL system, and the PCL porous scaffold prepared by the method has the following advantages: the structure of the PCL porous scaffold is a through-hole structure similar to a trabecular network, and has excellent blood moistening effect. The structure and mechanical properties of the scaffold can be controlled by the precursor slurry system and phase separation conditions. The preparation method is simple and easy to implement, and can realize large-scale production. On the basis of the preparation method, functional particles, surface modification and other methods can be further introduced to realize the optimization of the osteogenesis performance of the scaffold, or the functionalization and stem cell transplantation. BRIEF DESCRIPTION OF DRAWINGS
[0043] Figure 1The arbitrary plasticity, porous structure of the PCL scaffold prepared in Example One and its hemostatic effect (the top first row of the figure) are shown, as well as the SEM images showing the porous structure of the PCL scaffolds prepared in Example One, Example Two, Example Three, Example Four, Comparative Example One and Comparative Example Two.
[0044] Figure 2 The compression performance test results of the PCL scaffolds, PMMA scaffolds, HA scaffolds and 3D printed PLA scaffolds prepared in Example One, Comparative Example Three, Comparative Example Four and Comparative Example Five are shown, including compression curves, compression strength and modulus statistics.
[0045] Figure 3 The CT results of the PCL scaffolds, PMMA scaffolds, HA scaffolds and 3D printed PLA scaffolds prepared in Example One, Comparative Example Three, Comparative Example Four and Comparative Example Five implanted in the femoral half-truncated defect rats for one month are shown.
[0046] Figure 4 The CT parameter statistics of the PCL scaffolds, PMMA scaffolds, HA scaffolds and 3D printed PLA scaffolds prepared in Example One, Comparative Example Three, Comparative Example Four and Comparative Example Five implanted in the femoral half-truncated defect rats for one month are shown.
[0047] Figure 5 The slice staining images of the PCL scaffolds, PMMA scaffolds, HA scaffolds and 3D printed PLA scaffolds prepared in Example One, Comparative Example Three, Comparative Example Four and Comparative Example Five implanted in the femoral half-truncated defect rats for one month are shown.
[0048] Figure 6 The X-ray photos of the PCL scaffolds, PMMA scaffolds and HA scaffolds prepared in Example One, Comparative Example Three and Comparative Example Four implanted in the femoral condyle defect of a large animal, Bama pig, for 6 months are shown. DETAILED DESCRIPTION
[0049] The application will be further described in conjunction with specific examples, but the examples do not limit the application in any form. Unless otherwise specified, the reagents, methods and equipment used in the application are conventional reagents, methods and equipment in the technical field.
[0050] Example One:
[0051] (1) Prepare PCL / PEI precursor solution: add 6 g of PCL pellets with a molecular weight of 50,000 and 0.85 g of PEI with a molecular weight of 10,000 to 25 mL of DMF solution, and stir and dissolve at 60°C.
[0052] (2) Preparation of CNF dispersion: 8.3 g, 3 wt% of cellulose nanofiber (length 200-300 nm, diameter 3-20 nm, -COOH content 1.5 mmol / g) aqueous dispersion was diluted to 1 wt% with distilled water. Then 15 mL of DMF was added, and after mixing evenly, centrifugation was performed at 8000 r / min for 5 min. After centrifugation, the supernatant was poured out, and the DMF solvent was added to 45 mL and shaken evenly, and the above steps were repeated twice. Finally, the CNF was dispersed in the DMF solvent, and the dispersion volume was 25 mL.
[0053] (3) Vapor-induced phase separation to form the scaffold: the PCL / PEI solution in (1) and (2) was mixed with the CNF dispersion, and stirred at room temperature for 10 min to mix evenly. The mixed solution was transferred to a polytetrafluoroethylene or vaseline-coated aluminum mold, and the mold was placed in a crystallizing dish containing water, ensuring that the water solution did not submerge the mold. The crystallizing dish was covered with plastic wrap, and the entire device was placed in a 37°C oven. After 24 h, the device was removed, and the scaffold had formed.
[0054] (4) Scaffold post-processing: the mold was placed in distilled water, and the water was changed several times to replace the DMF solvent. After the scaffold hardened, it was removed from the mold and washed several times with water. The PEI and excess CNF in the scaffold voids were flushed away using a high-pressure water gun, and the residual DMF solvent was replaced with distilled water. Finally, the scaffold was dried at 60°C to obtain a PCL porous scaffold.
[0055] Example Two:
[0056] (1) Preparation of PCL / PEI / HA precursor solution: 6 g of 50,000 molecular weight PCL pellets and 0.85 g of 10,000 molecular weight PEI, and 0.3 g of HA nanoparticles were added to 25 mL of DMF solution and dissolved at 60°C with stirring.
[0057] (2) Preparation of CNF dispersion: 8.3 g, 3 wt% of cellulose nanofiber (length 200-300 nm, diameter 3-20 nm, -COOH content 1.5 mmol / g) aqueous dispersion was diluted to 1 wt% with distilled water. Then 15 mL of DMF was added, and after mixing evenly, centrifugation was performed at 8000 r / min for 5 min. After centrifugation, the supernatant was poured out, and the DMF solvent was added to 45 mL and shaken evenly, and the above steps were repeated twice. Finally, the CNF was dispersed in the DMF solvent, and the dispersion volume was 25 mL.
[0058] (3) Vapor induced phase separation to form the scaffold: Mix the PCL / PEI / HA solution in (1), (2) with the CNF dispersion solution, and stir at room temperature for 10 min to mix evenly. Transfer the mixed solution to a polytetrafluoroethylene or vaseline-coated aluminum mold, and place the mold in a crystallizing dish containing water, at which time the water solution in the dish should not submerge the mold. Cover the crystallizing dish with plastic wrap, and place the entire device in an oven at 37 °C. After 24 h, remove the device, at which time the scaffold has been formed.
[0059] (4) Post-processing of the scaffold: Place the mold in distilled water, and replace the DMF solvent multiple times. After the scaffold gradually hardens, remove the scaffold from the mold and continue to wash it with water multiple times. Use a high-pressure water gun to flush away the PEI and excess CNF in the scaffold interstices, and continue to replace the residual DMF solvent with distilled water. Finally, dry the scaffold at 60 °C to obtain a PCL / HA porous scaffold.
[0060] Example Three:
[0061] (1) Preparation of a PCL / PEI precursor solution: Add 6 g of PCL particles with a molecular weight of 50,000 and 1 g of PEI with a molecular weight of 10,000 to 25 mL of a DMF solution, and stir to dissolve at 60 °C.
[0062] (2) Preparation of a MCL dispersion solution: Dilute 8.3 g of microfibrillated cellulose (length greater than 20 μm, diameter 0.1-1 μm, PH: 7-8) to 1 wt% with distilled water. Add 15 mL of DMF, mix well, and then centrifuge at 8000 r / min for 5 min. After centrifugation, pour off the supernatant, add DMF solvent to 45 mL, shake well, and continue to centrifuge. Repeat the above steps twice, and finally disperse the MCL in the DMF solvent, with a volume of 25 mL.
[0063] (3) Vapor induced phase separation to form the scaffold: Mix the PMMA / PEI solution in (1), (2) with the MCL dispersion solution, and stir at room temperature for 10 min to mix evenly. Transfer the mixed solution to a polytetrafluoroethylene or vaseline-coated aluminum mold, and place the mold in a crystallizing dish containing water, at which time the water solution in the dish should not submerge the mold. Cover the crystallizing dish with plastic wrap, and place the entire device in an oven at 37 °C. After 24 h, remove the device, at which time the scaffold has been formed.
[0064] (4) Post-processing of the scaffold: Place the mold in water, and replace the DMF solvent multiple times. After the scaffold gradually hardens, remove the scaffold from the mold and continue to wash it with water multiple times. Use a high-pressure water gun to flush away the PEI, residual DMF solvent, and excess MCL in the scaffold interstices, and dry the scaffold at 60 °C to obtain a PCL porous scaffold.
[0065] Example Four
[0066] (1) Preparation of PCL / PEI precursor solution: 6 g, 50,000 molecular weight PCL pellets and 1 g, 10,000 molecular weight PEI were added to 25 mL DMF solution and dissolved by stirring at 60 °C.
[0067] (2) Preparation of BCL dispersion: 25 g, 0.8 wt% bacterial cellulose (length about 20 μm, diameter 50-100 nm, 1% NaOH purified) was added to 15 mL DMF and mixed well. Centrifugation was performed at 8000 r / min for 5 min. The supernatant was discarded and the volume of the DMF solvent was adjusted to 45 mL. The above steps were repeated twice. Finally, the BCL was dispersed in DMF solvent and the volume of the dispersion was 25 mL.
[0068] (3) Vapor-induced phase separation to form the scaffold: The PCL / PEI solution and BCL dispersion were mixed and stirred at room temperature for 10 min. The mixed solution was transferred to a polytetrafluoroethylene or vaseline-coated aluminum mold, and the mold was placed in a crystallizing dish containing water. The water level in the dish should not exceed the mold. The dish was covered with plastic wrap and the entire device was placed in a 37 °C oven. After 24 h, the device was removed and the scaffold had formed.
[0069] (4) Scaffold post-processing: The mold was placed in water and the water was changed several times to replace the DMF solvent. When the scaffold hardened, it was removed from the mold and washed with water several times. The PEI, residual DMF solvent and excess BCL in the scaffold voids were removed using a high-pressure water gun, and the scaffold was dried at 60 °C to obtain a PCL porous scaffold.
[0070] Comparative Example One
[0071] (1) Preparation of PCL precursor solution: 6 g, 50,000 molecular weight PCL pellets were added to 25 mL DMF solution and dissolved by stirring at 60 °C.
[0072] (2) Preparation of CNF dispersion: 8.3 g, 3 wt% cellulose nanofiber (length 200-300 nm, diameter 3-20 nm, -COOH content 1.5 mmol / g) was diluted to 1 wt% with distilled water. 15 mL DMF was added and mixed well. Centrifugation was performed at 8000 r / min for 5 min. The supernatant was discarded and the volume of the DMF solvent was adjusted to 45 mL. The above steps were repeated twice. Finally, the CNF was dispersed in DMF solvent and the volume of the dispersion was 25 mL.
[0073] (3) Vapor induced phase separation to form scaffold: The PCL solution in (1), (2) is mixed with CNF dispersion liquid, and stirred at room temperature for 10 min to mix evenly. The mixed solution is transferred to a polytetrafluoroethylene or vaseline-coated aluminum mold, and the mold is placed in a crystallizing dish containing water, at which time the water solution in the dish should not submerge the mold. The crystallizing dish is sealed with plastic wrap, and the entire device is placed in a 37 °C oven. After 24 h, the device is removed, and at this time the scaffold has been formed.
[0074] (4) Scaffold post-processing: The mold is placed in distilled water, and the residual DMF solvent is removed by multiple water changes. After the scaffold gradually hardens, the scaffold is removed from the mold and continues to be washed with water multiple times. The high-pressure water gun is used to flush away the excess CNF in the scaffold interstices, and the residual DMF solvent is replaced with distilled water. Finally, it is dried at 60 °C to obtain a PCL porous scaffold.
[0075] Comparative Example Two:
[0076] (1) Preparation of PCL / PEI precursor solution: 6 g of 50,000 molecular weight PCL pellets and 0.85 g of 10,000 molecular weight PEI are added to 25 mL of DMF solution and dissolved by stirring at 60 °C.
[0077] (2) Vapor induced phase separation to form scaffold: The PCL / PEI solution in (1) is transferred to a polytetrafluoroethylene or vaseline-coated aluminum mold, and the mold is placed in a crystallizing dish containing water, at which time the water solution in the dish should not submerge the mold. The crystallizing dish is sealed with plastic wrap, and the entire device is placed in a 37 °C oven. After 24 h, the device is removed, and at this time the scaffold has been formed.
[0078] (3) Scaffold post-processing: The mold is placed in distilled water, and the residual DMF solvent is removed by multiple water changes. After the scaffold gradually hardens, the scaffold is removed from the mold and continues to be washed with water multiple times. The high-pressure water gun is used to flush away the PEI in the scaffold interstices, and the residual DMF solvent is replaced with distilled water. Finally, it is dried at 60 °C to obtain a PCL porous scaffold.
[0079] Comparative Example Three:
[0080] (1) Preparation of PMMA / PEI precursor solution: 7 g of 100,000 molecular weight PMMA pellets and 1 g of 10,000 molecular weight PEI are added to 25 mL of DMF solution and dissolved by stirring at 60 °C.
[0081] (2) Preparation of CNF dispersion: 10 g, 3 wt% of cellulose nanofiber (length 200-300 nm, diameter 3-20 nm, -COOH content 1.5 mmol / g) was diluted to 1 wt% with distilled water. Then 15 mL of DMF was added, and after mixing, centrifugation was performed at 8000 r / min for 5 min. After centrifugation, the supernatant was poured out, and the DMF solvent was added to 45 mL and shaken evenly, and the above steps were repeated twice. Finally, the CNF was dispersed in the DMF solvent, and the dispersion volume was 25 mL.
[0082] (3) Vapor-induced phase separation to form the scaffold: the PMMA / PEI solution in (1) and (2) was mixed with the CNF dispersion, and stirred at room temperature for 10 min to mix evenly. The mixed solution was transferred to a polytetrafluoroethylene or vaseline-coated aluminum mold, and the mold was placed in a crystallizing dish containing water, ensuring that the water solution did not submerge the mold. The crystallizing dish was covered with plastic wrap, and the entire device was placed in a 37 °C oven. After 24 h, the device was removed, and the scaffold had been formed.
[0083] (4) Scaffold post-processing: the mold was placed in water, and the residual DMF solvent was removed by multiple water changes. The scaffold was removed from the mold and continued to be washed with water multiple times. The PEI and excess CNF in the scaffold interstices were washed away using a high-pressure water gun, and the scaffold was dried at 60 °C to obtain a PMMA porous scaffold.
[0084] Comparative Example Four:
[0085] (1) Preparation of hydroxyapatite (HA) / chitosan (CS) slurry: 0.2 g of CS powder was added to a 2 wt% acetic acid solution and stirred to dissolve. 6 g of HA powder was added to the CS solution in batches and stirred to disperse evenly in the solution.
[0086] (2) Preparation of porous HA scaffold: the above slurry was fully immersed in melamine foam (MF), and vacuum drying was performed at 60 °C to obtain a HA / CS / MF porous scaffold. Finally, the HA / CS / MF scaffold was sintered at 1250 °C to form a HA porous scaffold.
[0087] Comparative Example Five:
[0088] (1) Preparation of polylactic acid (PLA) / HA printing slurry: HA powder was dispersed in a commercial PLA photocuring printing liquid at 5 wt%, and stirred evenly in the dark.
[0089] (2) 3D printing of PLA / HA porous scaffold: using SLA photocuring printing technology, a PLA / HA porous scaffold was printed.
[0090] Next, the scaffolds prepared in the examples and comparative examples were structurally characterized and tested for performance, with the following results:
[0091] Figure One For the porous structure of the PCL scaffolds, i.e., Example One, Example Two, Example Three, Example Four, Comparative Example One and Comparative Example Two, it can be seen from the SEM results that we successfully prepared PCL porous scaffolds and PCL / HA scaffolds by the vapor-induced phase separation method. The scaffolds have a through-hole structure and also have a multi-level porous structure, which will be conducive to cell adhesion and calcium deposition. At the same time, the PCL scaffold also has the ability to be arbitrarily shaped, which will be conducive to clinical operation and the application scenario of irregular bone defects. Moreover, the formation of the scaffold has no skin effect, and has excellent blood moistening effect, a large number of growth factors and functional cells in the blood will greatly promote the bone repair ability of the scaffold. However, when PEI and CL are absent in the system, a uniform and perfect network structure as in Example One cannot be formed.
[0092] Figure Two For the compression performance test of PCL, PMMA, HA, 3D printed PLA scaffolds, including compression curve, compression strength and modulus statistics. It can be seen that the HA scaffold has the largest compression modulus, but due to its brittleness, it has the lowest compression strength. The 3D printed PLA and PMMA scaffolds are similar, both have high compression modulus and high compression strength. The PCL scaffold is relatively soft, and the entire scaffold shows excellent elasticity, with the smallest compression modulus and strength.
[0093] Figure Three For the CT display of PCL, PMMA, HA, 3D printed PLA scaffolds implanted in the rat femoral half-truncated defect for one month. It can be seen that PCL has more new bone formation than the other three scaffolds, and the defect forms a uniform network, and the new bone and the through-hole scaffold structure form an interpenetrating network structure. On this basis, the PCL scaffold will gradually degrade and be completely replaced by new bone in the future.
[0094] Figure Four For Figure Three The CT statistical data of the four scaffolds shown in Example 1, Example 2, Example 3, Example 4, Comparative Example 1 and Comparative Example 2 implanted in the rat femoral half-truncated defect for one month. It can be seen that PCL and PMMA scaffolds have more new bone formation inside. PCL, PMMA and HA scaffolds have a smaller pore structure than 3D printed PLA scaffolds, so they have a higher number of trabeculae. At the same time, PCL can form a thicker trabecular structure due to its self-degradability and elasticity.
[0095] Figure Five For Figure ThreeThe four kinds of stents shown in the middle of the rat femur half-truncated defect implantation one month after the section staining data. From Example One, we see that the new bone formation network and with PCL stent formed interpenetrating network structure, while the new bone and the original cortical bone stent has a good connection, which shows that the PCL stent has good bone induction, bone integration ability. But PMMA, with 3D printing PLA stent, although also can promote the new bone formation, but there are more bone hyperplasia. And the HA stent formed less new bone, and lack of connectivity.
[0096] Figure Six The repair results of the stents of Example One and Comparative Examples Three and Four implanted into the femoral condyle of Bama pigs for 6 months, PCL, PMMA and HA stents have good osteogenic effect on the defect, and the cortical bone is effectively closed. More importantly, PCL and PMMA stents have new bone formation in the defect area of the cortical bone extension area, and there is no ectopic bone formation in the bone marrow cavity, while the HA stent induces new bone formation in the area where HA is located. This shows that PCL and PMMA stents can well perceive the mechanical environment and have the performance of bone formation under the guidance of mechanics.
[0097] It should be noted that the specification and drawings of the present application give the preferred embodiments of the present application, but the present application can be implemented in many different forms, and is not limited to the embodiments described in the specification, and these embodiments are not additional limitations on the content of the present application. The purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive. And the above technical features continue to combine, form various embodiments not listed above, which are considered to be within the scope of the present application. Furthermore, for those skilled in the art, the above description can be improved or changed, and all these improvements and changes should be within the scope of the appended claims of the present application.
Claims
1. A porous polycaprolactone scaffold that is degradable in vivo and highly osteoconductive, characterized in that, The poly-caprolactone porous scaffold is formed by steam-induced phase separation using poly-caprolactone (PCL), polyethyleneimine (PEI) and cellulose (CL) as raw materials.
2. The polycaprolactone porous scaffold of claim 1, wherein, The poly-caprolactone porous scaffold has a through-hole structure similar to a bone trabecular network and a multi-level porous structure.
3. The polycaprolactone porous scaffold of claim 1, wherein, The mass ratio of PCL to PEI is 10:1-3:1; Further, the molecular weight of PCL is 30-300 thousand, and the molecular weight of PEI is 300-30,000; Further, the mass ratio of PCL+PEI to CL is 10:1-100:1; Further, the CL comprises microfibrillated cellulose (MCL), bacterial cellulose (BCL), cellulose nanofiber (CNF), wherein CNF is preferred, the diameter of CNF is 3-100 nm, the length is 100 nm-50 μm, and the content of-COOH is 0.2-3 mmol / g; Further, the raw materials of the poly-caprolactone porous scaffold further comprise inorganic particles; Further, the inorganic particles include hydroxyapatite, β-tricalcium phosphate, calcium sulfate or bioglass of any particle size and morphology; Further, the mass ratio of inorganic particles to PCL is 0:1-1:
1.
4. A method of preparing a polycaprolactone porous scaffold according to any one of claims 1-3, characterized in that, The method comprises the following steps: (1) preparing a PCL / PEI precursor solution: dissolving poly-caprolactone (PCL) and polyethyleneimine (PEI) in a polar organic solvent to obtain a PCL / PEI precursor solution; (2) preparing a CL dispersion: dispersing cellulose (CL) in an organic solvent to obtain a CL dispersion; (3) forming a scaffold by steam-induced phase separation: mixing the PCL / PEI precursor solution and the CL dispersion uniformly, and then precipitating the scaffold by steam-induced phase separation, and then performing post-treatment on the scaffold to obtain a PCL porous scaffold.
5. The method of claim 4, wherein, The concentration of the polymer in the PCL / PEI precursor solution is 5 wt%-40 wt%, and the mass ratio of PCL to PEI is 10:1-3:1; Further, the molecular weight of PCL is 30-300 thousand, and the molecular weight of PEI is 300-30,000; Further, the polar organic solvent is at least one of DMF, DMSO, NMP and DMA; Further, the mixing comprises stirring at 50-80 ℃; Further, the PCL / PEI precursor solution further comprises inorganic particles; Further, the inorganic particles include hydroxyapatite, β-tricalcium phosphate, calcium sulfate or bioglass of any particle size and morphology; Further, the mass ratio of inorganic particles to PCL is 0:1-1:
1.
6. The method of claim 4, wherein, Dispersing CL in an organic solvent comprises: first dispersing CL in water, and then replacing the water-dispersed CL with organic solvent-dispersed CL by centrifugal solvent replacement method; Further, the concentration of CL in the water dispersion is 0.2-3 wt%. Further, the CL comprises microfibrillated cellulose (MCL), bacterial cellulose (BCL), cellulose nanofiber (CNF), wherein CNF is preferred, the diameter of CNF is 3-100 nm, the length is 100 nm-50 μm, and the content of-COOH is 0.2-3 mmol / g; Further, the concentration of CL in the organic solvent is 0.2-5 wt%; Further, the organic solvent comprises at least one of DMF, DMSO, NMP, and DMA.
7. The method of claim 4, wherein, The ratio of solid content of the PCL / PEI precursor solution and the CL dispersion solution is 10:1-100:
1.
8. The method of claim 4, wherein, The steam-induced phase separation comprises placing the mixed solution of the PCL / PEI precursor solution and the CL dispersion solution in a mold, and then performing steam-induced phase separation in a sealed container containing water. Further, the temperature of the steam-induced phase separation is 5-60 ℃, and the time is 6-48 h.
9. The method of claim 4, wherein, The post-treatment of the scaffold comprises removing the organic solvent, PEI, and excess CL on the scaffold and drying; Further, the post-treatment of the scaffold comprises: after the scaffold is formed, placing the mold in water to replace the organic solvent, taking out the scaffold from the mold after the scaffold is hardened, rinsing to remove PEI and excess CL on the scaffold, and continuing to replace the residual organic solvent with water, and finally drying to obtain a PCL porous scaffold.
10. Use of the in-vivo degradable and highly osteogenic poly-caprolactone porous scaffold according to any one of claims 1-3 in repairing bone defects. Further, the poly-caprolactone porous scaffold is used as an artificial bone scaffold. Further, the bone defect comprises an extreme bone defect.