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1.
利用定向冰晶-冷冻干燥法制备了具有定向孔隙结构的磷酸钙骨水泥支架材料, 将两种具有不同降解速率的聚乳酸-羟基乙酸共聚物(PLGA) 与磷酸钙骨水泥多孔支架进行多次浸润复合, 以改善支架的力学性能。结果表明: PLGA 与支架材料复合可大大提高复合支架材料的抗压强度, 经过PLGA 二次复合后, 复合支架抗压强度可达6. 37 MPa ±0. 54 MPa 。经过PLGA 复合的支架材料保持了复合前的孔隙结构, 在孔的轴向方向上具有定向排列的开口孔隙, 这些开口孔隙的存在有利于植入初期新生组织的长入。覆盖在骨水泥基体表面的PLGA 膜可以增强基体的强度并弥补基体表面的缺陷, 充填在孔隙内部的PLGA 泡沫体可以很好地承受外加载荷, 使复合支架材料具有较好的强度和韧性。   相似文献   

2.
To enhance tissue ingrowth and promote rapid resorption, efforts were made to build macropores into calcium phosphate cement (CPC); however, this led to a decrease in its mechanical properties. In this study, poly (lactic-co-glycolic acid) (PLGA) microspheres were incorporated into CPC to impart macroporosity and maintain early strength. The influences of the content of PLGA microspheres on the mechanical strength, rheological properties, injectability, setting time, and microstructure of CPC were also systematically investigated. At the PLGA to CPC mass ratios of 20/80 and 30/70, the compressive strength of the composites was similar to that of CPC without PLGA microspheres. The rheological results indicated that PLGA microspheres/CPC pastes showed plastic and shear-thinning behaviors. The addition of PLGA microspheres to CPC resulted in the increase of viscosity and yield stress of the pastes. Simultaneously, the injectability of the pastes decreased with the addition of PLGA microspheres. When the PLGA to CPC ratio was 20/80, the injectability of the paste was still higher than 95%. The calcium phosphate cement containing 20 wt.% PLGA microspheres exhibited excellent injectability and satisfactory setting time without strength degradation. Obviously, such an in situ macropores-generable CPC should have potential prospects for the wider applications in orthopedics, oral, and maxillofacial surgery.  相似文献   

3.
磷酸钙/纤维蛋白胶复合支架材料的结构及力学性能分析   总被引:17,自引:0,他引:17  
用可吸收磷酸钙骨水泥和纤维蛋白胶按一定比例体外构建复合支架材料,通过XRD、SEM、抗压实验和空隙率测试等方法对其结构及力学性能进行分析.结果发现:由于加入纤维蛋白胶,复合支架材料在一定程度上延长了磷酸钙骨水泥的初凝时间,但并不影响磷酸钙骨水泥的终凝时间;同时,加入纤维蛋白胶改变了骨水泥固化体的微观结构,提高了骨水泥的抗压强度,其最大抗压强度达到14MPa,弹性模量在96.64~269.39MPa之间,空隙率为38.8%.与在同样条件下制备的磷酸钙骨水泥比较,复合支架材料的抗压强度增强了55.6%,而空隙率仅仅下降了6.9%;XRD分析显示,复合支架材料并不影响磷酸钙骨水泥的最终的转化,其结晶结构仍是羟基磷灰石结构,是更好的骨组织工程支架材料.  相似文献   

4.
本研究采用球磨对磷酸钙骨水泥(CPC)起始粉末进行机械活化处理, 以期改善CPC力学性能, 并探讨了其影响机理。采用激光粒度仪、比表面积测量仪和X射线衍射仪(XRD)表征球磨后的CPC粉末(Ball milling CPC, BCPC)。利用发泡法制备多孔BCPC支架, 采用万能力学试验机、XRD和扫描电子显微镜(SEM)表征多孔BCPC支架。结果显示, 球磨后的BCPC粉末平均粒径减小, 比表面积增大, 表观密度、堆积密度及紧密密度减小。BCPC支架孔隙率为(77.98 ± 0.58)%, 抗压强度为(4.11 ± 0.46) MPa, 相比CPC支架的(64.23 ± 2.32)%和(1.99 ± 0.43) MPa有显著提高。SEM结果显示BCPC支架具有数微米和数百微米的两种孔隙结构。XRD结果表明机械活化作用降低了DCPD、α-TCP、CaCO3和HA的晶粒尺寸和结晶度, 促使DCPD向DCPA转化, 促进了各相磷酸钙盐的水化和HA的沉积, 提高了BCPC支架的力学性能, 为增强CaP基多孔材料的力学性能和扩展其临床应用提供了新途径。  相似文献   

5.
Mesoporous calcium sulfate-based bone cements (m-CSBC) were prepared by introducing mesoporous magnesium–calcium silicate (m-MCS) with specific surface area (410.9 m² g−1) and pore volume (0.8 cm³ g−1) into calcium sulfate hemihydrate (CSH). The setting time of the m-CSBC was longer with the increase of m-MCS content while compressive strength decreased. The degradation ratio of m-CSBC increased from 48.6 w% to 63.5 w% with an increase of m-MCS content after soaking in Tris–HCl solution for 84 days. Moreover, the m-CSBC containing m-MCS showed the ability to neutralize the acidic degradation products of calcium sulfate and prevent the pH from dropping. The apatite could be induced on m-CSBC surfaces after soaking in SBF for 7 days, indicating good bioactivity. The effects of the m-CSBC on vitamin D3 sustained release behaviours were investigated. It was found that the cumulative release ratio of vitamin D3 from the m-CSBC significantly increased with the increase of m-MCS content after soaking in PBS (pH = 7.4) for 25 days. The m-CSBC markedly improved the cell-positive responses, including the attachment, proliferation and differentiation of MC3T3-E1 cells, suggesting good cytocompatibility. Briefly, m-CSBC with good bioactivity, degradability and cytocompatibility might be an excellent biocement for bone regeneration.  相似文献   

6.
在柠檬酸中添加壳聚糖配成的固化液与磷酸钙骨水泥(CPC)调和制备的骨修复材料具有类似口香糖的胶状特性, 可应用于碎骨粘结, 称之为磷酸钙骨粘合剂(CPCBA)。本研究考察了柠檬酸的含量对抗压强度、固化时间、水化产物和粘结强度的影响, 同时对该体系进行了初步的体外生物学评价。结果显示, 加入柠檬酸可以缩短固化时间并且时间可以通过柠檬酸的含量进行调控, 同时也改善了抗水性能。壳聚糖可以与骨水泥中的钙离子发生螯合作用, 可以增加界面的粘结强度。小鼠原成骨细胞(MC3T3-E1)在其表面粘附良好, 该体系骨水泥有望取代PMMA成为新的骨粘结剂。  相似文献   

7.
《Materials Letters》2004,58(3-4):397-402
Porous calcium phosphates have important biomedical applications such as bone defect fillers, tissue engineering scaffolds and drug delivery systems. While a number of methods to produce the porous calcium phosphate ceramics have been reported, this study aimed to develop a new fabrication method. The new method involved the use of polyurethane foams to produce highly porous calcium phosphate cements (CPCs). By firing the porous CPCs at 1200 °C, the polyurethane foams were burnt off and the CPCs prepared at room temperature were converted into sintered porous hydroxyapatite (HA)-based calcium phosphate ceramics. The sintered porous calcium phosphate ceramics could then be coated with a layer of the CPC at room temperature, resulting in high porosity, high pore interconnectivity and controlled pore size.  相似文献   

8.
Calcium silicate possessed excellent biocompatibility, bioactivity and degradability, while the high brittleness limited its application in load-bearing sites. Hydroxyapatite whiskers ranging from 0 to 30 wt.% were incorporated into the calcium silicate matrix to improve the strength and fracture resistance. Porous scaffolds were fabricated by selective laser sintering. The effects of hydroxyapatite whiskers on the mechanical properties and toughening mechanisms were investigated. The results showed that the scaffolds had a uniform and continuous inner network with the pore size ranging between 0.5 mm and 0.8 mm. The mechanical properties were enhanced with increasing hydroxyapatite whiskers, reached a maximum at 20 wt.% (compressive strength: 27.28 MPa, compressive Young's modulus: 156.2 MPa, flexural strength: 15.64 MPa and fracture toughness: 1.43 MPa·m1/2) and then decreased by addition of more hydroxyapatite whiskers. The improvement of mechanical properties was due to whisker pull-out, crack deflection and crack bridging. Moreover, the degradation rate decreased with the increase of hydroxyapatite whisker content. A layer of bone-like apatite was formed on the scaffold surfaces after being soaked in simulated body fluid. Human osteoblast-like MG-63 cells spread well on the scaffolds and proliferated with increasing culture time. These findings suggested that the calcium silicate scaffolds reinforced with hydroxyapatite whiskers showed great potential for bone regeneration and tissue engineering applications.  相似文献   

9.
Abstract

In this study, a core/shell bi-layered calcium phosphate cement (CPC)-based composite scaffold with adjustable compressive strength, which mimicked the structure of natural cortical/cancellous bone, was fabricated. The dense tubular CPC shell was prepared by isostatic pressing CPC powder with a specially designed mould. A porous CPC core with unidirectional lamellar pore structure was fabricated inside the cavity of dense tubular CPC shell by unidirectional freeze casting, followed by infiltration of poly(lactic-co-glycolic acid) and immobilization of collagen. The compressive strength of bi-layered CPC-based composite scaffold can be controlled by varying thickness ratio of dense layer to porous layer. Compared to the scaffold without dense shell, the pore interconnection of bi-layered scaffold was not obviously compromised because of its high unidirectional interconnectivity but poor three dimensional interconnectivity. The in vitro results showed that the rat bone marrow stromal cells attached and proliferated well on the bi-layered CPC-based composite scaffold. This novel bi-layered CPC-based composite scaffold is promising for bone repair.  相似文献   

10.
Injectable calcium sulphate/phosphate cement (CSPC) with degradable characteristic was developed by introduction of calcium sulphate (CS) into calcium phosphate cement (CPC). The setting time, compressive strength, composition, degradation, cells and tissue responses to the CSPC were investigated. The results show that the injectable CSPC with optimum L/P ratio exhibited good injectability, and had suitable setting time and mechanical properties. Furthermore, the CSPC had good degradability and its degradation significantly faster than that of CPC in Tris–HCl solution. Cell culture results indicate that CSPC was biocompatible and could support MG63 cell attachment and proliferation. To investigate the in vivo biocompatibility and osteogenesis, the CSPC were implanted in the bone defects of rabbits. Histological evaluation shows that the introduction of CS into CPC enhanced the efficiency of new bone formation, and CSPC exhibited good biocompatibility, degradability and osteoconductivity with host bone in vivo. It can be concluded that the injectable CSPC had a significant clinical advantage over CPC, and might have potential to be applied in orthopedic, reconstructive and maxillofacial surgery, especially for minimally invasive techniques.  相似文献   

11.
To develop high macroporous and degradable bone cements which can be used as the substitute of bone repairing and drug carriers, cross-linked gelatin microspheres (GMs) and calcium sulfate dihydrate (CSD) powder were incorporated into calcium phosphate bone cement (CPC) to induce macropores, adjust drug release and control setting time of α-TCP–liquid mixtures after degradation of GMs and dissolution of CSD. In this study, CSD was introduced into CPC/10GMs composites to offset the prolonged setting time caused by the incorporation of GMs, and gentamicin sulphate (GS) was chosen as the model drug entrapped within the GMs. The effects of CSD amount on the cement properties, drug release ability and final macroporosity after GMs degradation were studied in comparison with CPC/GMs cements. The resulting cements presented reduced setting time and increased compressive strength as the content of CSD below 5 wt%. Sustained release of GS was obtained on at least 21 days, and release rates were found to be chiefly controlled by the GMs degradation rate. After 4 weeks of degradation study, the resulting composite cements appeared macroporous, degradable and suitable compressive strength, suggesting that they have potential as controlled local drug delivery system and for cancellous bone applications.  相似文献   

12.
通过化学发泡-冷冻干燥-粒子滤出复合法制备聚乳酸(PLLA)大孔支架, 然后在大孔内以海藻酸钠(SA)、碳酸钙、葡萄糖酸内酯(GDL)为原料, 通过原位相转变制备海藻酸钙水凝胶/聚乳酸复合材料(CA/PLLA); 分别利用SEM、压缩强度测试和细胞培养对CA/PLLA支架的形貌、力学性能及生物相容性进行了研究。结果表明: PLLA具有直径小于2 mm、孔道相互连通的孔洞, 且在大孔中能够形成均匀的CA。CA/PLLA复合材料的压缩强度(2.74 MPa)远大于单一的海藻酸钙水凝胶的压缩强度(0.10 MPa)。在CA/PLLA复合支架中, 软骨细胞呈簇状圆形生长状态, 与其在天然软骨陷窝里生长状态一致。这种软硬结合、天然与合成高分子杂化的CA/PLLA复合材料的力学强度和生物相容性同时得到提高, 可进一步作为骨和软骨修复材料研究。  相似文献   

13.
包峰  常江 《无机材料学报》2021,36(11):1199-1207
电纺丝支架已被广泛用于组织工程领域, 其中硅酸钙等生物活性陶瓷复合的电纺丝支架, 在应用中展现出了优异的生物活性。硅酸钙复合电纺丝支架中硅酸钙降解释放的硅酸根离子(SiO32-)已被证实具有促进成血管性能, 但其有效活性离子浓度范围比较窄, 仅在0.79~1.8 μg/mL之间。因此精确控制组织工程材料的离子释放浓度, 使材料释放的离子能较长时间保持在有效活性浓度范围, 对于组织工程应用具有重要意义。本研究通过调节电纺丝孔径大小及硅酸钙纳米线的不同复合方式, 制备了多种硅酸钙复合电纺丝纤维支架, 并比较了其在体外环境下的离子释放模式及对人脐静脉内皮细胞的增殖促进作用。实验结果表明, 混纺及同时电喷-电纺复合方式的小孔径硅酸钙复合电纺支架由于高分子的疏水作用和小孔径结构对离子扩散的阻碍, 可以实现离子缓释。通过体外细胞实验发现, 具有离子缓释效果的支架可以更好地促进人脐静脉内皮细胞的增殖, 说明通过调控支架离子缓释, 可以有效调控其生物活性, 获得最佳组织工程应用效果。  相似文献   

14.
In bone tissue engineering, a highly porous artificial extracellular matrix or scaffold is required to accommodate cells and guide the tissue regeneration in three-dimension. Calcium phosphate (CaP) ceramics are widely used for bone substitution and repair due to their biocompatibility, bioactivity, and osteoconduction. However, compared to alumina ceramics, either in the dense or porous form, the mechanical strength achieved for calcium phosphates is generally lower. In the present work, the major goal was to develop a tri-dimensional macroporous alumina scaffold with a biocompatible PVA/calcium phosphate coating to be potentially used as bone tissue substitute. This approach aims to combine the high mechanical strength of the alumina scaffold with the biocompatibility of calcium phosphate based materials. Hence, the porous alumina scaffolds were produced by the polymer foam replication procedure. Then, these scaffolds were submitted to two different coating methods: the biomimetic and the immersion in a calcium phosphate/polyvinyl alcohol (CaP/PVA) slurry. The microstructure, morphology and crystallinity of the macroporous alumina scaffolds samples and coated with CaP/PVA were characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM/EDX) analysis. Also, specific surface area was assessed by BET nitrogen adsorption method and mechanical behavior was evaluated by axial compression tests. Finally, biocompatibility and cytotoxicity were evaluated by VERO cell spreading and attachment assays under SEM. The morphological analysis obtained from SEM photomicrograph results has indicated that 3D macroporous alumina scaffolds were successfully produced, with estimated porosity of over 65% in a highly interconnected network. In addition, the mechanical test results have indicated that porous alumina scaffolds with ultimate compressive strength of over 3.0 MPa were produced. Concerning to the calcium phosphate coatings, the results have showed that the biomimetic method was not efficient on producing a detectable layer onto the alumina scaffolds. On the other hand, a uniform and adherent inorganic–organic coating was effectively formed onto alumina macroporous scaffold by the immersion of the porous structure into the CaP/PVA suspension. Viable VERO cells were verified onto the surface of alumina porous scaffold samples coated with PVA–calcium phosphate. In conclusion, a new method was developed to produce alumina with tri-dimensional porous structure and uniformly covered with a biocompatible coating of calcium phosphate/PVA. Such system has high potential to be used in bone tissue engineering.  相似文献   

15.
A novel calcium phosphate silicate bone cement (CPSC) was synthesized in a process, in which nanocomposite forms in situ between calcium silicate hydrate (C–S–H) gel and hydroxyapatite (HAP). The cement powder consists of tricalcium silicate (C3S) and calcium phosphate monobasic (CPM). During cement setting, C3S hydrates to produce C–S–H and calcium hydroxide (CH); CPM reacts with the CH to precipitate HAP in situ within C–S–H. This process, largely removing CH from the set cement, enhances its biocompatibility and bioactivity. The testing results of cell culture confirmed that the biocompatibility of CPSC was improved as compared to pure C3S. The results of XRD and SEM characterizations showed that CPSC paste induced formation of HAP layer after immersion in simulated body fluid for 7 days, suggesting that CPSC was bioactive in vitro. CPSC cement, which has good biocompatibility and low/no cytotoxicity, could be a promising candidate as biomedical cement.  相似文献   

16.
The addition of growth factors, such as recombinant human transforming growth factor‐β1 (rhTGF‐β1) to calcium phosphate cements (CPCs) may improve bone regeneration. Previously we have shown that the differentiation of pre‐osteoblastic cells from adult rat long bones was stimulated by rhTGF‐β1 in CPC. CPC that was intermixed with rhTGF‐β1 and then applied in rat calvarial defects enhanced bone growth around the cement and increased the degradation of the cement. It is still unknown however whether the addition of rhTGF‐β1 changes the material properties of the CPC, and what the release characteristics are of rhTGF‐β1 from the CPC. We therefore determined here the release of rhTGF‐β1 in vitro from the cement pellets as implanted in the rat calvariae. The possible intervening effects of rhTGF‐β1‐intermixing on clinical compliance of CPC were studied by assessing its compressive strength and setting time, as well as crystallinity, calcium to phosphorus ratio, porosity and microscopic structure. CPC was prepared by mixing calcium phosphate powder (58% α‐tricalcium‐phosphate, 25% dicalcium‐phosphate anhydrous, 8.5% calcium‐carbonate and 8.5% hydroxyapatite), with liquid (3 g/ml). The liquid for standard CPC consisted of water with 4% sodium hydrogen phosphate, while the liquid for modified CPC, was mixed with an equal amount of 4 mM hydrochloride with 0.2% bovine serum albumin. The hydrochloride liquid contained the rhTGF‐β1 in different concentrations for the release experiments. Most of the incorporated rhTGF‐β1 in the cement pellets was released within the first 48 hr. Approximately 0.5% rhTGF‐β1 (intermixed at 100 ng to 2.5 mg/g CPC) was released within the first 4 hr increasing to 1% after 48 hr. rhTGF‐β1 release continued at 0.1% up to at least 8 weeks. Modification of CPC slightly increased the initial setting time at 20°C from 2.6 to 5 min, but did not affect the final setting time of the CPC at 20°C, nor the initial and final setting time at 37°C. The compressive strength was increased from 18 MPa (standard CPC) to 28 MPa (modified CPC) only at 4 hr after mixing. The compressive strength diminished in the modified CPC between 24 hr and 8 weeks from 55 to 25 MPa. X‐ray diffraction revealed that both standard and modified CPC changed similarly from the basic components, alpha‐tri‐calcium phosphate and dicalcium phosphate anhydrous, into an apatite cement. The calcium to phosphorus ratio as determined by an electron microprobe did not differ for standard CPC and modified CPC. Standard and modified CPC became a dense and homogeneous structure after 24 hr, but the modified CPC contained more crystal plaques compared to the standard CPC, as observed by scanning electron microscopy (SEM). SEM and back scattered electron images revealed that after 8 weeks both cements showed an equally and uniform dense structure with microscopic pores (less than 1 μm). Both CPCs showed fewer crystal plaques at 8 weeks than at 24 hr. This study shows that the calcium phosphate cement was not severely changed by modification of the CPC for rhTGF‐β1. Clinical handling may be affected by the prolonged setting time of modified cement, but it is still within preferable limits. Compressive strength was for both standard and modified cements within the range of thin trabecular bone, and therefore both CPCs can withstand equal mechanical loading. The faster diminishing compressive strength of modified cement (from 24 hr to 8 weeks) likely results in early breakdown, and therefore might be favourable for bone regeneration. Together with our previous studies showing the beneficial effects of adding rhTGF‐β1 to CPC on bone regeneration, we conclude that the envisaged applications for CPC in bone defects are upgraded by intermixing of rhTGF‐β1. Therefore the combination of CPC with rhTGF‐β1 forms a promising synthetic bone graft.  相似文献   

17.
In the present study, cetyltrimethyl ammonium bromide (CTAB) was introduced to an injectable calcium phosphate cement (CPC) to produce macropores during the setting process to accelerate the absorbing ability in vivo. The effects of CTAB on the rheological properties, injectability, setting time, compressive strength, phase evolution, microstructure and degradation rate of CPC were studied. The results showed that the addition of CTAB increased the viscosity and yield stress, and decreased the injectability of the cement pastes. The macroporosity and total porosity increased and the compressive strength of the cement obviously decreased with the increase of CTAB. The macroporosity of the CPC prepared at 5 mM CTAB solution reached 44.2 +/- 2.5% and the mass loss of the cement increased almost 50% as compared with the cement without CTAB. Considering the injectability, compressive strength and degradation rate of CPC, the preferred CTAB concentration was 5 mM. The injectable CPC with macropores is promising to be used in minimally invasive approach.  相似文献   

18.
A key requirement for three-dimensional printing (3-DP) of medical implants is the availability of printable and biocompatible powder-binder systems. In this study we developed a powder mixture comprising tetracalcium phosphate (TTCP) as reactive component and β-tricalcium phosphate (β-TCP) or calcium sulfate as biodegradable fillers, which can be printed with an aqueous citric acid solution. The potential of this material combination was demonstrated printing various devices with intersecting channels and filigree structures. Two post-processing procedures, a sintering and a polymer infiltration process were established to substantially improve the mechanical properties of the printed devices. Preliminary examinations on relevant application properties including in vitro cytocompatibility testing indicate that the new powder-binder system represents an efficient approach to patient specific ceramic bone substitutes and scaffolds for bone tissue engineering.  相似文献   

19.
Porous magnesium has the potential to be used as degradable bone scaffolds. In this study, porous magnesium scaffolds were fabricated through powder metallurgy route utilizing spherical naphthalene particle as porogen. Porogen was removed at 120?°C for 24?h followed by sintering at 550?°C for 2?h in argon atmosphere. Micro-computed tomography (micro CT) results indicated that scaffolds have interconnected porous structure with an equivalent pore diameter of nearly 60?µm. Compressive strength of the scaffolds was found in the range of 24?±?4.54?MPa to 184?±?9.9?MPa and decreased with increasing porogen content. In vitro degradation study in phosphate buffered saline (PBS) showed that scaffold degradation behavior was governed by its porosity content. Our results indicate that modulating the porogen content we can tailor the mechanical and degradation behavior of the Mg scaffolds to the application need.  相似文献   

20.
利用棒状谷氨酸钠晶体作为造孔粒子,采用可溶盐造孔法,制备了三维连通的大孔径多孔磷酸钙骨水泥支架,分别将明胶(Gelatin) 、聚乳酸2羟基乙酸共聚物(PLGA) 、聚乳酸(PLA) 、聚己内酯(PCL) 、聚羟基丁酸戊酸酯(PHBV)灌注到多孔磷酸钙骨水泥(CPC)支架的孔隙中以改善支架材料的力学性能。结果表明,5 种高分子材料与水的接触角大小顺序为PHBV > PCL > PLA > PL GA > Gelatin , 复合支架材料的强度随高分子材料与水接触角的减小而增大;除PHBV外,其余4种均有明显的增强效果,其中Gelatin/CPC复合支架增强效果最好,强度达到2. 25 MPa±0. 02 MPa ,是CPC支架强度的25倍。经过增强的大孔径多孔磷酸钙骨水泥复合支架可用作骨组织工程支架材料。   相似文献   

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