共查询到19条相似文献,搜索用时 203 毫秒
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用于骨组织工程的羟基丁酸-戊酸共聚物/生物活性玻璃复合多孔支架材料 总被引:10,自引:0,他引:10
研究了用于骨组织工程的复合型羟基丁酸-戊酸共聚物/溶胶-凝胶生物活性玻璃多孔支架材料,采用溶液浇注沥滤法制备了任意形状的三维连通多孔结构支架,并进行三维结构表征和显微形貌观察;通过对成型条件的调节,可控制支架的孔径和孔隙率;在模拟生理体液中进行复合支架材料的生物活性测试。研究表明,通过控制致孔剂用量、尺寸大小和分散,得到的支架材料呈三维连通开孔结构,且孔隙分布均匀、孔隙率达90%以上;扫描电镜观察结果显示,羟基丁酸-戊酸共聚物与生物活性玻璃良好相容,后者粘附在支架孔壁上;支架在模拟生理体液中浸泡后发现生物活性玻璃表面有羟基碳酸磷灰石多晶体生成,表明复合支架仍保持了BG的生物活性。 相似文献
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合金多孔化是有效降低材料弹性模量的方式之一,采用添加造孔剂的元素粉末冶金法制备了新型医用多孔Ti-14Mo-2.1Ta-0.9Nb-7Zr合金,通过扫描电镜、阿基米德法、X射线衍射和压缩力学性能测试的方法研究了不同造孔剂用量和粒径尺寸对合金形貌特征、孔隙率、物相组成及力学性能的影响规律。结果表明:该方法制备所得多孔Ti-14Mo-2.1Ta-0.9Nb-7Zr合金为近β型钛合金;随着造孔剂用量增加,平均孔径无变化,孔隙率呈线性增长,弹性模量和抗压强度减小,其中弹性模量的变化满足线性关系;随着造孔剂粒径尺寸增加,平均孔径增大而孔隙率基本不变,抗压强度和弹性模量减小;添加20%(质量分数)粒径尺寸为125~200μm的NH4HCO3造孔剂制备多孔Ti-14Mo-2.1Ta-0.9Nb-7Zr合金,于1300℃烧结4h孔隙率达到38.9%并含有贯穿孔结构,抗压强度达到405 MPa,而弹性模量为9.19GPa,能满足医用植入材料的要求。 相似文献
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采用相分离和盐析复合工艺,通过改变冷却温度、溶液浓度、溶剂/水比例、造孔剂用量等工艺制备聚己内酯多孔支架,通过扫描电镜观察支架形貌,采用压汞仪测量支架孔隙率及孔径,研究各工艺条件对支架多级孔径结构的影响.研究表明冷却温度-70℃、PCL溶液浓度10%、溶剂/水比例95/5、80%质量含量的粒径100~200μm NaCl造孔剂为最佳实验条件,可制备出具有100~350μm大孔、5~30μm小孔及<10nm微孔的聚己内酯复合多级孔径支架,孔隙率高,连通性好,可应用于骨组织工程支架. 相似文献
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This paper reports polymeric scaffolds with spherical internal macropores and relatively large external dimension. Paraffin
spheres with the diameter of several hundred microns were prepared by a suspension technique. Particulate leaching technique
based on this kind of spherical porogens was combined with room-temperature compression molding technique to fabricate biodegradable
poly(D,L-lactic-co-glycolic acid) (PLGA) porous scaffolds potentially for tissue engineering or in situ tissue induction. The scaffolds exhibited ordered macropores with good pore interconnectivity. The porosity ranged from 80
to 97% adjusted simply by varying porogen content. The foams with porosity around 90% have compressive modulus over 3 MPa
and compressive strength over 0.2 MPa. As preliminary cell experiments with 3T3 fibroblasts cultured on the porous scaffolds
indicate, the processing procedure of the scaffolds has not brought with problem in cytotoxicity. 相似文献
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Biodegradable polycaprolactone scaffold with controlled porosity obtained by modified particle-leaching technique 总被引:1,自引:0,他引:1
Lebourg M Sabater Serra R Más Estellés J Hernández Sánchez F Gómez Ribelles JL Suay Antón J 《Journal of materials science. Materials in medicine》2008,19(5):2047-2053
Scaffold with controlled porosity constitute a cornerstone in tissue engineering, as a physical support for cell adhesion
and growth. In this work, scaffolds of polycaprolactone were synthesized by a modified particle leaching method in order to
control porosity and pore interconnectivity; the aim is to observe their influence on the mechanical properties and, in the
future, on cell adhesion and proliferation rates. Low molecular weight PEMA beads with an average size of 200 μm were sintered
with various compression rates in order to obtain the templates (negatives of the scaffolds). Then the melt polycaprolactone
was injected into the porous template under nitrogen pressure in a custom made device. After cooling and solidifying of the
melt polymer, the porogen was removed by selective dissolution in ethanol. The porosity and morphology of the scaffold were
studied as well as the mechanical properties. Porosities from 60% to 85% were reached; it was found that pore interconnectivity
logically increases with increasing porosity, and that mechanical strength decreases with increasing porosity. Because of
their interesting properties and interconnected structure, these scaffolds are expected to find useful applications as a cartilage
or bone repair material. 相似文献
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Although three-dimensional fibroin scaffolds have been prepared with freeze drying method, the porosity and pore sizes still
can not satisfy the requirement of tissue engineering. In this article, fibroin porous scaffold with high porosity and > 100μm
diameter interconnected pores was firstly prepared with freeze drying method through adjusting fibroin concentration. The
morphology of different scaffolds lyophilized from different fibroin concentration was observed by SEM. A novel freeze drying
improved method, freeze drying/foaming technique, was also devised to prepare fibroin scaffolds at different fibroin concentrations.
Using the said method, the porosity and pore size of fibroin scaffolds prepared from 12% concentration were 85.8 ± 4% and
109 ± 20 μm respectively with yield strength up to 450 ± 6 KPa while the porosity and pore size of fibroin scaffolds prepared
from 8% concentration were 96.9 ± 3.6% and 120 ± 30 μm respectively with yield strength up to 30 ± 1 KPa. The freeze drying/foaming
technique produced scaffolds with a useful combination of high yield strength, interconnected pores, and pore sizes greater
than 100 μm in diameter. Through adjusting fibroin concentration and thawing time, the porosity, pore sizes and mechanical
properties could be controlled to satisfy the different requirements of tissue engineering. The results suggested that fibroin
scaffolds prepared with the above methods could be formed for utility in biomaterial application. 相似文献
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Ghosh S Viana JC Reis RL Mano JF 《Journal of materials science. Materials in medicine》2007,18(2):185-193
One of the most widely used fabrication methods of three dimensional porous scaffolds involves compression moulding of a polymer
salt mixture, followed by salt leaching. However, the scaffolds prepared by this technique have typically limited interconnectivity.
In this study, besides salt particles, an additional polymeric porogen, poly(ethylene oxide), PEO, was added to poly(L-lactic
acid), PLLA, to enhance the interconnectivity of the scaffolds. Compression moulded specimens were quenched and put into water,
where PEO crystallized and phase separated. Following the leaching of PEO fraction, the permeability and interconnectivity
among the macropores formed by salt leaching could be observed. The porosities obtained in the prepared scaffolds were between
76 to 86%. Moreover, the highest porosity of 86% was obtained with minimum fraction of total porogen. The water absorption
of the porous scaffolds prepared with PEO could vary between 280 to 450% while water uptake of pure PLLA scaffolds was about
93%. The increase of interconnectivity induced by compounding PLLA with PEO could also be obtained in porous PLLA/starch blends
and PLLA/hydroxyapatite composites demonstrating the versatility and wide applicability of this preparation protocol. The
simplicity of this organic solvent free preparation procedure of three-dimensional porous scaffolds with high interconnectivity
and high surface area to volume ratio holds a promise for several tissue engineering applications. 相似文献
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Will J Melcher R Treul C Travitzky N Kneser U Polykandriotis E Horch R Greil P 《Journal of materials science. Materials in medicine》2008,19(8):2781-2790
Hydroxyapatite scaffolds with a multi modal porosity designed for use in tissue engineering of vascularized bone graft substitutes were prepared by three dimensional printing. Depending on the ratio of coarse (mean particle size 50 microm) to fine powder (mean particle size 4 microm) in the powder granulate and the sintering temperature total porosity was varied from 30% to 64%. While macroscopic pore channels with a diameter of 1 mm were created by CAD design, porosity structure in the sintered solid phase was governed by the granulate structure of the printing powder. Scaffolds sintered at 1,250 degrees C were characterized by a bimodal pore structure with intragranular pores of 0.3-0.4 microm and intergranular pores of 20 microm whereas scaffolds sintered at 1,400 degrees C exhibit a monomodal porosity with a maximum of pore size distribution at 10-20 microm. For in-vivo testing, matrices were implanted subcutaneously in four male Lewis rats. Scaffolds with 50% porosity and an average pore size of approximately 18 microm were successfully transferred to rats and vascularized within 4 weeks. 相似文献
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In Vitro Characterizations of PLLA/β-TCP Porous Matrix Materials and RMSC-PLLA-β-TCP Composite Scaffolds 总被引:1,自引:0,他引:1
Dali ZHOU Weizhong YANG Guangfu YIN Changqiong ZHENG Yun ZHANG School of Materials Science Engineering Sichuan University Chengdu China Huaiqing CHEN Rui CHEN Institute of Biomedical Engineering West China Center of Medical Science Sichuan University Chengdu China 《材料科学技术学报》2004,20(3):248-252
To develop a novel degradable poly (L-lactic acid)/β-tricalcium phosphate (PLLA/β-TCP) bioactive materials for bone tissueengineering, β-TCP powder was produced by a new wet process. Porous scaffolds were prepared by three steps, i.e. solventcasting, compression molding and leaching stage. Factors influencing the compressive strength and the degradation behaviorof the porous scaffold, e.g. weight fraction of pore forming agent-sodium chloride (NaCl), weight ratio of PLLA: β-TCP,the particle size of β-TCP and the porosity, were discussed in details. Rat marrow stromal cells (RMSC) were incorporatedinto the composite by tissue engineering approach. Biological and osteogenesis potential of the composite scaffold weredetermined with MTT assay, alkaline phosphatase (ALP) activity and bone osteocalcin (OCN) content evaluation. Resultsshow that PLLA/β-TCP bioactive porous scaffold has good mechanical and pore structure with adjustable compressive strengthneeded for surgery. RMSCs seeding on porous PLLA/ 相似文献
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具有良好贯通性的颗粒造孔支架的制备及表征 总被引:1,自引:0,他引:1
支架孔隙贯通性的研究一直是多孔生物陶瓷的研究重点之一.采用石蜡球作为造孔剂, 在常规的颗粒造孔法制备多孔陶瓷支架的基础上,通过二甲苯处理以便在石蜡球间形成桥联结构, 以扩大颗粒间的接触面积,从而提高多孔陶瓷支架的孔隙贯通性. 借助扫描电镜(SEM)观察陶瓷支架的多孔结构,评价二甲苯处理石蜡球对陶瓷支架孔隙贯通性的改善效果; 采用密度法测定了陶瓷支架的孔隙率并计算其收缩率,并用成骨细胞评价陶瓷支架的细胞相容性. 结果表明,通过二甲苯的处理, 不仅改善了陶瓷支架孔隙的贯通性,而且提高了其孔隙率, 但孔隙率对陶瓷支架的收缩率无明显影响.细胞培养实验显示成骨细胞可进入多孔陶瓷支架内部, 并在材料表面正常生长,贯通性好的多孔陶瓷支架可为成骨细胞生长提供更充分的空间. 相似文献
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浆料粘度是热诱导相分离法制备支架材料的关键因素,采用不同粘度的纳米羟基磷灰石/聚酰胺66(n-HA/PA66)复合浆料制备了相应的n-HA/PA66多孔支架,并对不同粘度浆料制备支架材料的泡孔结构和力学性能等进行了对比研究。结果表明,浆料粘度对n-HA/PA66复合多孔支架的孔径、孔径分布、孔隙率、开孔率、力学强度等性能有显著的影响。随着浆料粘度的增大,制备支架的孔径、孔隙率、开孔率逐渐减小,而力学强度却逐渐增大。当浆料粘度为330Pa.s时,制备出的n-HA/PA66复合多孔支架综合性能最好,其孔径主要分布在200~500μm,平均孔径(324±67.1)μm,孔隙率为(75±1.6)%,开孔率为(59±2.5)%,抗压强度为(2.12±0.90)MPa,能够较好地满足骨组织工程支架材料对孔径、孔隙率和力学性能的要求。 相似文献
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磷灰石-硅灰石/β-磷酸三钙复合多孔支架材料的制备和表征 总被引:5,自引:0,他引:5
以磷灰石-硅灰石玻璃陶瓷(AW)粉和β-磷酸三钙(β-TCP)粉为原料. 以硬脂酸为致孔剂. 经模压成型、1170℃烧结制备磷灰石-硅灰石/β-磷酸三钙复合多孔支架材料(AW/βTCP). 采用X射线衍射(XRD)、扫描电镜(SEM)、能谱(EDS)、诱导耦合等离子体原子发射光谱(ICP-AES)等方法分析支架的晶相组成、显微结构、物理性能、生物活性和降解性. 将大鼠骨髓间充质干细胞(rMSCs)与支架体外复合培养评价支架的生物相容性. 结果表明: 所制备的AW/β-TCP支架材料的抗压强度达14.3MPa. 孔隙率达66.9%. 孔径为100~700μm. 具有良好的生物相容性、生物活性和降解性. 可作为骨组织工程支架的候选材料. 相似文献