PLGA/HA骨支架材料的降解特性

采用有机泡沫法获得了HA多孔骨架.运用溶胶浇铸法将PLGA溶胶填充入多孔骨架中,制备出骨组织工程用PLGA/HA复合支架材料,并考察了其在模拟体液中的降解性能,通过SEM观察了其表面组织形貌.结果表明,随浆料中HA含量的增加,材料降解后质量损失增大,且随降解时间的延长,PLGA/HA骨支架材料表面粘附的磷灰石相增多,表明该复合材料具有良好的生物活性.     

纳米羟基磷灰石/聚合物多孔复合支架材料

为提高骨组织工程支架材料的力学性能,改善其生物活性,综合天然与合成高分子的优点,采用溶液共混相分离法制备出聚己内酯(PCL)-壳聚糖(CS)多孔支架材料, 并进一步采用离心注浆法填充具有生物活性的纳米羟基磷灰石(HA)-聚乙烯醇(PVA)复合浆料, 制备了n-HA-PVA/PCL-CS复合多孔支架材料, 改善了PCL-CS支架材料力学性能。采用扫描电子显微镜、红外光谱、元素分析、孔隙率和抗压强度试验对材料进行了表征。结果表明, PCL-CS支架材料的内部具有蜂窝状的相互贯通的孔隙结构,孔隙率可以达到60%～80%。CS含量越大,孔隙率越大,而抗压强度越小。填充后的n-HA-PVA/PCL-CS复合多孔支架材料,孔隙率有所下降,但仍大于60%,而其弹性模量可提高至25.71 MPa。      

碳酸氢铵和聚乙烯醇复合造孔制备多孔陶瓷及其性能研究

以羟基磷灰石(HA)为基体,采用添加NH4HCO3晶粒并加热去除的方法制备多孔羟基磷灰石(HA)陶瓷,制备过程中同时加入一定量的生物玻璃来增加其强度,添加一定量的聚乙烯醇(PVA)来提高其结合性能和改善贯通性.对制备的多孔生物陶瓷试样进行硬度和抗压强度试验,讨论不同组分对其性能的影响规律,采用扫描电镜对多孔陶瓷试样的微观结构进行分析.结果表明,随着NH4HCO3含量的增加,多孔生物陶瓷试样的孔隙率和硬度增加,抗压强度下降,孔径约为200～300μm;随着PVA含量的增加,试样孔隙率增大,贯通性增强,孔道长度约为1～3mm,孔径在100μm以下;随着生物玻璃含量的增加,试样的体积收缩明显,微孔增多.     

聚乳酸涂层改善网状羟基磷灰石陶瓷支架力学性能的研究

采用有机泡沫浸渍法制备出高孔隙率的三维网状羟基磷灰石(HA)生物陶瓷支架,并采用不同浓度的聚乳酸(PDLLA)溶液涂覆网状HA支架,以达到增强补韧网化陶瓷支架的目的.通过扫描电镜观察PDLLA涂覆网状HA陶瓷支架的显微结构和测试力学强度,研究了不同浓度PDLLA溶液涂覆对网状HA支架的涂层厚度、显微结构和力学性能的影响.实验结果表明:涂覆一定量的PDLLA涂层可以显著提高网状HA生物陶瓷支架的抗压强度,同时保持网状陶瓷支架的贯通性和孔隙率.     

注射成型羟基磷灰石/聚酰胺6多孔支架的微观结构和力学性能

采用注射成型法制备了羟基磷灰石/聚酰胺6(HA/PA6)多孔支架,用SEM、XRD、DSC等手段表征了支架的组成结构和形貌,检测了其力学性能.研究表明,调节羟基磷灰石(HA)含量、偶氮二甲酰胺(AC)用量和预塑量能有效控制支架的力学性能、孔径大小和孔隙率.HA/PA6支架的孔径在100～500μm左右,孔隙率达到甚至超...     

脂肪族聚氨酯/磷灰石复合材料的原位制备及性能

为避免芳香族聚氨酯在体内降解时产生有毒物质,选用生物相容性良好的脂肪族聚氨酯(PU)与生物活性的羟基磷灰石(HA)为原料,通过原位聚合法制备了脂肪族PU/HA组织工程用多孔支架,并采用SEM、IR和力学试验等方法对多孔支架的形貌和性能进行了表征,进一步研究了发泡剂(水)用量和HA含量对支架泡孔结构和力学强度的影响。结果表明,当发泡剂用量为1%～1.5%(质量分数)时制得的多孔PU/HA复合支架材料孔隙之间相互贯通,孔径范围分布在300～800μm,大孔壁上分布着孔径为50～200μm的小孔,孔隙率达80%以上。随HA含量增加,支架抗压强度和弹性模量显著上升。综合考虑HA的增强效果和组织工程支架的孔隙结构,本体系中HA的最佳添加量为40%(质量分数),发泡剂的最佳用量为1%(质量分数)。     

双交联明胶-壳聚糖复合人工真皮支架的制备及其性能研究

采用1-乙基-(3-二甲基氨基丙基)碳化二亚胺盐酸盐(EDC.HCl)和三聚磷酸钠(STPP)作为共价-离子双交联剂交联制备了明胶-壳聚糖(gel-CS)复合人工真皮支架。通过FT-IR和SEM对复合多孔支架结构及形貌进行表征,同时对复合多孔支架的孔隙率、平均孔径、溶胀性能和降解性能进行了研究。研究结果表明,明胶和壳聚糖两相间成功地发生了交联反应,形成了具有贯通孔结构和良好孔隙率的复合多孔支架。该支架平均孔径在136.1～182.9μm之间,且随着壳聚糖含量的增加,孔径及孔隙率随之降低;溶胀性能研究发现,相较于单一共价交联方法,采用双交联法制备的支架溶胀率有所降低,再次印证双交联法制备的支架其交联度较单一共价交联的高;酶降解实验表明,固定STPP含量,随着EDC含量增加,复合支架的降解性能越好,而EDC含量一定,则STPP含量为0.5%时,复合支架具有最好的降解性能。     

硼硅酸盐生物活性玻璃多孔支架的制备

Na2O-CaO-SiO2-P2O5-B2O3系硼硅酸盐生物玻璃是一类具有良好生物活性和降解性能的组织工程材料.本研究中,采用有机泡沫浸渍法,乙醇作溶剂,乙基纤维素作添加剂,将硼硅酸盐玻璃粉体制备成具有三维连通网状结构的组织工程多孔支架.通过调节浆料的固相含量和乙基纤维素含量,改善坯体的涂覆量,在支架孔径为300～500um,孔隙率高于80%时,使支架抗压强度从0.03MPa提高到0.36MPa.根据蜂窝状结构模型分析,发现采用高强度玻璃,优化浆料是改善多孔材料结构和力学性能的有效途径.用该模型理论指导,由Na2O-CaO-SiO2-P2O5-B2O3系统制成的另一种硼硅酸盐玻璃支架,其抗压强度可达5～8MPa.实验表明有机泡沫浸渍法在制备组织工程支架中有广泛的应用前景.     

纳米羟基磷灰石/聚乙烯醇复合人工角膜材料

用纳米HA 与聚乙烯醇(PVA) 制备了一种新型人工角膜, 光学中心采用柔韧透明的PVA 水凝胶, 周边支架采用纳米HA 与PVA 复合的多孔水凝胶, 该设计有利于提高人工角膜支架与宿主角膜组织的生物性结合, 同时从工艺上解决了光学中心与周边支架的结合问题。研究结果表明, 复合材料中纳米HA 与PVA 具有相互作用;纳米HA 在复合材料中均匀分散;多孔复合水凝胶具有良好的显微结构。用光学显微镜对该人工角膜光学中心和支架结合部观察, 表明二者通过互穿网络结构形成了紧密结合。动物实验术后进行裂隙灯和组织学观察表明该复合人工角膜的生物相容性好, 人工角膜支架与宿主角膜组织可生物性愈合, 该人工角膜具有很好的临床应用前景。     

复合磷酸盐多孔生物陶瓷的制备及体外细胞相容性

以Al₂O₃-MgO-P₂O₅磷酸盐为粘结剂, 采用有机泡沫浸渍工艺制备了多孔陶瓷, 采用扫描电镜(SEM)、X射线衍射(XRD)、排水法和压缩实验等表征了多孔陶瓷的孔隙形貌、相组成、孔隙率和力学性能, 并通过体外细胞实验研究了其细胞相容性. 结果表明, Al₂O₃-MgO-P₂O₅磷酸盐的加入不仅可以使浆料能够均匀地涂覆在泡沫体上, 也促进了陶瓷的烧结. 得到的多孔陶瓷具有相互连通、分布均匀的孔隙结构(大孔孔径在100~500μm, 还有约为3μm微孔), 平均孔隙率为85.9%±1.6%, 平均压缩强度为(1.04±0.15)MPa; 多孔陶瓷虽然是一种由HA、β-Ca₂P₂O₇和少量含Mg、Al的物相组成的复合磷酸盐陶瓷, 但在体外实验中没有表现出明显的细胞毒性, 并能促进细胞快速增殖与分化, 表明该多孔陶瓷具有良好的细胞亲和性和相容性.     

Preparation and characterization of nano-hydroxyapatite/polymer composite scaffolds

Polycaprolactone/chitosan (PCL/CS) porous composite scaffolds were prepared by solution phase separation method, and the scaffolds were further enhanced by filling with nano-hydroxyapatite/polyvinyl alcohol (n-HA/PVA) composite slurry to prepare n-HA-PVA/PCL-CS composite porous scaffolds through slurry centrifugal filling technique. The morphology, microstructure, component, porosity and mechanical property of the scaffolds were characterized using scanning electron microscope, X-ray diffraction, Fourier transform infrared spectroscope, elemental analyzer and material test machine. The results show that PCL/CS scaffolds have mutual transfixion porous structure just like honeycombs. The porosity of the scaffolds can achieve 60-80%. As the content of CS increases, the porosity increases while the compressive strength decreases. After filled with HA/PVA composite slurry, the porosity of n-HA/PCL-CS composite scaffolds decreases, but still greater than 60%, while the compression modulus can increase to 25.7 MPa.     

蜡球造孔法制备多孔HA陶瓷支架及其性能优化

组织工程支架的贯通性对其体内生物学表现具有重要影响。采用甲壳素溶胶体系和蜡球造孔剂制备多孔羟基磷灰石(HA)陶瓷支架, 考查在相同模压条件下, 不同浆料/造孔剂比例对多孔HA陶瓷支架的孔隙率、收缩率、贯通性、多孔结构以及抗压强度的影响。结果表明: 该方法可以制备具有高孔隙的多孔HA陶瓷支架, 随着造孔剂比例的增大, 支架的贯通性更好, 当浆料/造孔剂比例为1:1.2时可以得到孔隙率、贯通性、力学性能最优的多孔HA陶瓷支架。     

Controllable porosity hydroxyapatite ceramics as spine cage: fabrication and properties evaluation

A procedure was designed to prepare porosity-graded hydroxyapatite (HA) ceramics simulating the bimodal structure of natural bone, which could be used to build a cage that would promote the reconstruction of the anterior column after vertebrectomy or corpectomy in tumor and trauma surgery. HA ceramics with controllable pore size distribution and porosity were developed by using chitosan and Poly(vinyl alcohol) (PVA) as the pore-forming agents. HA ceramics with worthwhile properties such as a wide range of volume porosity (10-50%) and pore size (nanometer to 400 microm) can be obtained from this method, which allows the fabrication of HA ceramics with desirable porous characteristics simulating the bimodal natural bone architecture expected to provide advantages for bony fusion in the intervertebral foramina. When coated with chitosan-gelatin network, the bending strength of the porous HA ceramics significantly improved. The polymer network coated porous HA have potential application in the construction of cages for spinal operations.     

Fabrication of 1-dimensional porous hydroxyapatite and evaluation of its osteoconductivity

Porous HA ceramics with 1-dimensional pore channels were fabricated to obtain controllable microstructure. 1-dimensional porous HA was objected to find out the optimum condition of bone ingrowth and also to facilitate the observation of osteocondutive behavior in porous HA. The porous structure was formed by burnt-out of polymeric fibers and the size of pores was determined by the diameter of polymeric fibers. The porosity could be varied by the thickness of HA slurry coated on polymeric fiber and by the thickness of HA tapes inserted between fiber layers. As result, 1-dimensional porous HA ceramics of this study have the uniform interconnection size (50-500 microm) and the linearly open pore structure. The compressive strength of 1-dimensional porous HA was 6-10 MPa similar to that of human cancellous bone. On the in vivo test, oteon-like osteoconduction in pore channel of 1-dimensional porous HA was observed, like what had been found in cortical bones. This osteon-like new bone grew from the surface to the center of pore channels. The 1-dimensional porous HA ceramics prepared in this study were very useful as a model system to observe bone ingrowth in the porous HA implants.     

用冰模板法制备羟基磷灰石多孔陶瓷

使用水基羟基磷灰石(HA,Ca5(PO4)3OH)浆料,用冰模板法制备定向层状多孔HA陶瓷,研究了浆料中HA陶瓷颗粒含量和冷端温度的影响.结果表明:随着浆料中HA陶瓷颗粒含量的提高,浆料的粘度值增大,层状多孔结构的层厚度相应增加,孔道层间距减小甚至消失,多孔材料的抗压强度从1.4 MPa提高到5.7 MPa,孔隙率从7...     

致密羟基磷灰石球粒的制备及其生物学性能研究

使用羧甲基壳聚糖(CMCS)和明胶(Gel)作为粘结剂, 以沉淀法制得的纳米羟基磷灰石(HA)浆料为原料, 采用溶胶-凝胶法制备出了粒径分布均匀, 几何形态良好的致密HA球粒. 其孔隙率为4.7%±0.6%, 单粒抗压强度为(8.9±0.4) MPa(颗粒直径为0.5 mm), 高于孔隙率为16.4%±0.5%的多孔球的抗压强度(7.9±0.2) MPa。仿生矿化和细胞培养的结果显示致密HA球粒具有良好的生物学性能。     

Influence of preparation method on hydroxyapatite porous scaffolds

Hydroxyapatite (HA) is extensively used in medical applications as an artificial bone because of its similarity to the natural components of human bones and for its excellent biocompatibility. The porous structure of HA ceramics is more generally used as a scaffold. Many techniques, which are performed under fluid system, have been applied to fabricate HA porous scaffolds. In this work, polymeric sponge technique was employed in the preparation of HA slurry appropriated for porous ceramic fabrication. Effort for strength improvement was made on porous HA ceramic in several aspects. The effect of HA/water, binder/plasticizer ratios and dispersant content on the rheological properties of HA suspension in combination with the addition of SiC and SiO₂ on the compressive strength of porous bodies were investigated and discussed.     

Forming and sintering of porous calcium-hexaaluminate ceramics with hydraulic alumina

We have developed a new eco-friendly fabrication process for porous ceramics using hydraulic alumina (HA) and water. In the present study, we fabricated porous calcium-hexaaluminate (CaAl₁₂O₁₉, CA6) ceramics using this new process. A boehmite gel 3-D network was formed by the hydration of HA in HA/CaCO₃ mixed slurry. The HA/CaCO₃ mixed slurry was hardened by the formation of this 3-D network. Even without the addition of an organic binder, green bodies containing the 3-D network demonstrated high compressive strength and retained their original shapes. Furthermore, the water acted as a fugitive material in the green bodies. Consequently, the open porosity of the CA6 ceramics could be controlled over a wide range of 42–62.7% by the addition of water (ratio of water to HA/CaCO₃ mixed powder: 0.4 to 1.6 by weight) without the use of organic fugitive materials. The results of evolved gas analysis-mass spectrometry measurements showed that the emissions from the hardened green body consisted mostly of water. Consequently, the new fabrication process for porous calcium-hexaaluminate ceramics was confirmed to be eco-friendly.     

羟基磷灰石陶瓷管的制备

采用两种羟基磷灰石(HA)的成浆方法,使用不同的成管芯体吸附HA料浆,并设计相应的凝固浴实现HA管的初定型以及烧结程序,扫描电镜观察表明,采用DMA c/L iC l/CT/HA系和PVA/HA系两种陶瓷配浆体系,形成的HA管形貌有显著的不同;详细探讨了HA管制作的工艺过程和样品成型的各种影响因素;样品的X射线衍射图谱分析制作工艺未使烧结后的HA陶瓷管引入异质成分。