聚醚醚酮/牙源性双相生物陶瓷复合材料的制备及力学性能

背景：牙齿的物理性质和化学组成与人体骨组织极为相似,且无机成分所占比例较大,因此可以考虑将牙齿作为一个潜在的自体或同种异体骨缺损修复材料。 目的：制备聚醚醚酮/牙源性双相生物陶瓷复合材料,并测试其机械性能。 方法：收集临床上废弃的人离体牙,经初步煅烧去除有机成分,将其浸泡于磷酸氢二铵溶液24 h后再次煅烧,制备成以羟基磷灰石和β-磷酸三钙为主要成分的双相陶瓷,粉碎后过200目筛,采用有机泡沫浸渍法制备出聚醚醚酮/牙源性双相生物陶瓷,行物相分析、扫描电镜、元素分析、孔隙率、抗压强度、黏结强度检测。 结果与结论：聚醚醚酮/牙源性双相生物陶瓷为多孔网状结构,且孔间相互连通,孔径100-800 µm,孔隙率为73.65%,抗压强度为(165.260±11.703) N,黏结强度为(14.63±6.21) MPa,陶瓷中P元素含量占19.8%、Ca元素含量占40.5%,主要物相为β-磷酸三钙、羟基磷灰石。结果说明制备的聚醚醚酮/牙源性双相生物陶瓷具有良好的力学性能。  中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

人脐血间充质干细胞与β-磷酸三钙的生物相容性

背景：体内实验显示,β-磷酸三钙多孔陶瓷是较为理想的骨组织工程支架材料,但由于体内植入实验受多种因素的影响,不能很好反映细胞的生长、增殖和表型变化。 目的：观察体外人脐血间充质干细胞与β-磷酸三钙多孔陶瓷的生物相容性。 方法：将培养的第6代人脐血间充质干细胞悬液滴注入β-磷酸三钙内部进行复合,然后将干细胞-支架材料复合物置入含体积分数为10%胎牛血清的α-MEM培养体系中培养,于培养第4,8,12天电镜下观察人脐血间充质干细胞在材料表面及内部生长情况,采用MTT测试法绘制细胞生长曲线,并进行DNA含量、蛋白质含量测定。 结果与结论：人脐血间充质干细胞与β-磷酸三钙体外复合后能够在β-磷酸三钙支架材料表面及内部的孔隙内贴附,且生长良好,其DNA复制和蛋白合成功能不受β-磷酸三钙的影响。说明人脐血间充质干细胞和β-磷酸三钙支架材料生物相容性良好,二者可作为种子细胞和支架材料用于组织工程化骨与软骨的构建。     

钙磷生物陶瓷多孔骨修复材料的制备*

以适量的Mg(H2PO4)2-(NaPO3)6为粘结剂,HA和-TCP粉末为原料,用有机泡沫浸渍法制备钙磷多孔生物陶瓷坯体,并在850℃烧成,探索在较低烧结温度下制备钙磷多孔生物陶瓷的工艺。采用X射线衍射(XRD)、扫描电镜(SEM)、能谱(EDS)等方法对多孔生物陶瓷的物相组成、显微结构、物理性能进行了分析。烧成后的钙磷生物陶瓷多孔支架主要由-TCP、-Ca2P2O7和CaO-MgO-Na2O-P2O5磷酸盐玻璃组成。烧结过程中,HA发生了向-TCP的转化,部分-TCP转化为-Ca2P2O7。多孔支架具有良好三维连通性的孔隙结构,孔径为200～500m,孔隙率达81%,抗压强度为1.1～1.5MPa。     

磷酸三钙陶瓷材料形状对大鼠体内成血管化的影响

背景：组织工程人工骨支架材料的大体和微观结构可加速血管化进程。 目的：观察不同形状β-磷酸三钙陶瓷骨在体内的血管化程度,探索载体材料形状对体内血管化的影响。 方法：将柱状和管状两种β-磷酸三钙陶瓷骨材料分别植入SD大鼠两侧腰背筋膜下。 结果与结论：①同位素扫描结果：术后第3,6,12周,管状β-磷酸三钙陶瓷骨材料放射性核素骨显影放射性计数明显高于柱状β-磷酸三钙陶瓷骨材料(P < 0.05),并且随着时间的延长,两组放射性核素骨显影放射性计数均呈上升趋势。②扫描电镜观察结果：第3周时,材料外形保持良好,宿主纤维组织和血管由材料外周向内生长;术后6周时,管状材料内小血管增生活跃,且分布比较均匀,柱状材料血管增生主要集中在外周部分;术后12周时,两组材料血管化程度更高,管状材料外周及中心部位均可见较为成熟的纤维组织和丰富血管网,但柱状材料纤维组织和血管主要集中在外周部分,中轴部分较少。表明管状三维结构β-磷酸三钙陶瓷骨材料较柱状材料更利于体内血管化。     

复合水凝胶人工角膜裙边支架材料的生物相容性评价

背景：β-磷酸三钙/聚乙烯醇复合水凝胶具有高含水量、良好柔软性优点,有利于成纤细胞生长及胶原沉积,适用于做人工角膜裙边支架材料。 目的：评价β-磷酸三钙/聚乙烯醇复合水凝胶人工角膜裙边支架材料的生物相容性。 方法：①迟发型超敏反应：在豚鼠脊柱两侧皮内由头到尾分别注射A液(完全弗氏佐剂与生理盐水等体积混合液)、B液(β-磷酸三钙/聚乙烯醇复合水凝胶浸提液或生理盐水或2-巯基苯并噻唑)、C液(A液与B液等体积混合稳定性乳化剂),并进行局部诱导及激发。②急性全身性毒性实验：由昆明小鼠尾静脉分别注射生理盐水与β-磷酸三钙/聚乙烯醇复合水凝胶浸提液。③体外细胞毒性实验：分别以β-磷酸三 钙/聚乙烯醇复合水凝胶浸提液、细胞培养液及含苯酚的细胞培养液培养MRC-5细胞。④皮内反应：在兔脊柱皮内分别注射β-磷酸三钙/聚乙烯醇复合水凝胶生理盐水(或芝麻油)浸提液、生理盐水及芝麻油。 结果与结论：β-磷酸三钙/聚乙烯醇复合水凝胶人工角膜裙边支架材料的迟发型超敏反应分级为0-1级,急性全身毒性实验结果为正常无症状,体外细胞毒性均为0级或1级,皮内反应为极轻微。表明β-磷酸三钙/聚乙烯醇复合水凝胶人工角膜裙边支架材料生物相容性指标达到生物植入医用材料的要求。     

高性能多孔β-磷酸三钙生物陶瓷制备新工艺研究

开发了一个制备高性能多孔高纯 β-磷酸三钙 ( β- TCP)陶瓷新工艺 ,采用湿法工艺 ,将自制高纯、超细 ( 1～几 μm)的高纯、超细 Ca CO3调和成浆料加入到分析纯磷酸配制成的一定浓度的磷酸溶液中反应 ,配料按 Ca/ P原子比为 1.50。反应在搅拌和超声波震荡下进行 ,并在 10 min内完成 ,制得组成为Ca3( PO4 ) 2 n H2 O的 TCP前驱体沉淀 ,该沉淀粒度细 ( 0 .8～几 μm)而均匀 ,过滤性能优良 ,固液能快速分离。用 3% PVA溶液作粘结剂 ,2 0～ 30目的柱状硬脂酸作成孔剂 ,经压模成型、干燥、在 1170℃下煅烧制得高性能多孔 β- TCP生物陶瓷。研究表明 ,Ca CO3粒度对 TCP前驱体粒度、β- TCP陶瓷的孔隙率、抗压强度以及溶解速度均有影响 ,根据临床应用需要可以通过选用不同 Ca CO3粒度及致孔剂形状大小来调节陶瓷的孔隙率、孔结构 ,以控制陶瓷强度和溶解速度     

双相钙磷生物陶瓷/硫酸钙骨水泥多孔三维支架的生物性能

背景：随着组织工程技术的发展,多孔生物陶瓷被越来越多的运用到骨缺损的修复中,当前的研究主要集中在这种生物陶瓷的合成及其各项性能的评价。 目的：研究一种新型骨水泥的制备方法并测定其理化性能及与成骨细胞的生物相容性。 方法：共沉淀法制备双相钙磷生物陶瓷粉体,利用胶体团聚成颗粒,烧结后得到颗粒状、多孔羟基磷灰石/磷酸三钙生物陶瓷,并按不同比例与高纯度医用半水硫酸钙混合制备钙磷陶瓷/硫酸钙骨水泥。 结果与结论：X射线衍射证实合成物质为双相钙磷陶瓷,颗粒状双相钙磷陶瓷具有多孔网状结构,骨水泥在   3 min内保持可塑状态,固化时间为15 min,固化温度为36.5 ℃,压缩强度最高为5.82 MPa,MTT毒性级为0级,成骨细胞在材料表面生长良好。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

双相磷酸钙涂覆羟基磷灰石多孔支架的制备及性能

背景：目前的人工骨大多只能制备成小体积的填充用材料,大段负重骨及大块结构性植骨材料仍面临缺乏理想骨缺损修复材料和材料成型过程难以加工调控两大难题。目的：制备与人体大段负重骨形貌结构相似且兼具一定力学性能、优良生物相容性和部分可降解性的多孔羟基磷灰石/双相磷酸钙涂层复合支架,评估其性能。方法：采用水热合成法结合喷雾干燥技术分别制备羟基磷灰石粉体、羟基磷灰石晶须和β-磷酸三钙粉体,评估羟基磷灰石粉体、β-磷酸三钙粉体浸提液的细胞毒性。在羟基磷灰石粉体中添加不同含量(5%,10%,15%)的晶须,借助3D打印技术制备成多孔骨支架,设置不同的烧结工艺,通过正交实验筛选力学性能、孔隙率等最优的晶须含量与烧结工艺组合,检测最优组合支架的流体力学。采用浸渍提拉法将双相磷酸钙涂层涂覆在多孔骨支架上,体外评估双相磷酸钙涂层中β-磷酸三钙粉体的降解性能。结果与结论：(1)MTT实验显示,羟基磷灰石粉体、β-磷酸三钙粉体无明显的细胞毒性;(2)正交实验结果显示,影响多孔支架抗压强度最主要的因素为烧结温度,其次是晶须含量,最后是烧结时间;各因素组合中的最优组合为晶须含量10%、烧结温度1 300℃、烧结时间3...     

多孔生物陶瓷与PVA水凝胶复合材料的制备与力学性能分析

目的将多孔生物陶瓷和聚乙烯醇(PVA)水凝胶交联成为一个仿生软骨-硬关节双层结构,并对该结构的微观形貌和力学性能进行分析。方法以羟基磷灰石(HA)为基体,采用添加碳酸氢铵(NH4HCO3)晶粒造孔的方式制备不同孔隙率的多孔羟基磷灰石生物陶瓷,以聚乙烯醇(PVA)为主要原料,环氧丙烷为交联剂,在多孔生物陶瓷表面及基体内交联制备出PVA水凝胶形成双层结构,对试样的断口形貌进行表征,对试样的拉伸强度和剪切强度等性能进行测试分析。结果交联的PVA水凝胶可以渗入到生物陶瓷基体表层以下的孔隙中,并且陶瓷基体和PVA水凝胶有很好的结合。随着多孔生物陶瓷孔隙率的增大,试样的最大拉伸和剪切负载均增大,平均孔隙率为70%试样的最大拉伸和剪切负载分别为153.61 N和64.46 N;而相应的拉伸和剪切强度略有下降,平均孔隙率为30%试样对应的最大拉伸和剪切强度分别为2.12 MPa和1.13 MPa。两者的失效形式均是因为裂纹的扩展,断口的微观形貌表明,断裂面存在明显的裂纹和内部缺陷,同时可观察出裂纹源和扩展方向。结论考虑到多孔生物陶瓷基体的强度,平均孔隙率为50%的多孔生物陶瓷的渗入效果适中,试样的拉伸强度和剪切强度、多孔生物陶瓷基体的压缩强度也有一定的保证,选择孔隙率为50%的试样较为合适。     

无机纳米粒子掺杂生物活性碳纳米纤维的制备及性能评价

背景：已有研究表明向生物惰性碳纳米纤维中引入具有成骨活性的β-磷酸三钙纳米粒子,可显著提高碳纳米纤维的生物活性,而某些二价离子掺杂的β-磷酸三钙也被报道能够促进新骨的生成。 目的：考察适量锌离子、镁离子的引入对β-磷酸三钙@碳纳米纤维材料形貌及成骨活性的影响。 方法：以聚丙烯腈、磷酸三乙酯、硝酸钙、硝酸锌、硝酸镁等为原料,采用溶胶-凝胶、静电纺丝与原位烧结碳化相结合的方法制备锌或镁离子掺杂的β-磷酸三钙@碳纳米纤维材料。将所得复合纳米纤维材料及未掺杂锌或镁离子掺杂的β-磷酸三钙@碳纳米纤维与成骨细胞MC3T3-E1体外共培养,观察细胞的黏附、增殖和形态变化。 结果与结论：β-磷酸三钙@碳纳米纤维形貌均匀,表面可见直径为数十纳米的无机粒子均匀分布,锌或镁离子的引入对纤维形貌无明显影响;复合纤维主要由碳元素组成,钙、锌、镁元素等均匀分布于纤维中,且各元素相对含量与投料比相符。与未掺杂锌或镁离子的β-磷酸三钙@碳纳米纤维相比,MC3T3-E1成骨细胞更易在锌或镁离子掺杂的β-磷酸三钙@碳纳米纤维材料表面黏附,细胞增殖和铺展状态也更好。表明在β-磷酸三钙@碳纳米纤维的基础上,引入锌或镁离子掺杂,能进一步提高材料的细胞相容性及生物活性。     

Preparation of interconnected highly porous polymeric structures by a replication and freeze-drying process

Three-dimensional degradable porous polymeric structures with high porosities (93-98%) and well-interconnected pore networks have been prepared by freeze-drying polymer solutions in the presence of a leachable template followed by leaching of the template. Templates of the pore network were prepared by fusing sugar or salt particles to form a well-connected structure. The interstices of the template were then filled with a polymer solution (5-15% w/v) in 1,4-dioxane, followed by freeze-drying of the solvent. Subsequent leaching of the sugar template ensures the connectivity of the pore network. The scaffold architecture consists of relatively large interconnected pores modeled after the template and smaller pores resulting from the freeze-drying process. The total porosity of the resultant porous structures is determined by the interstitial space of the leachable template and by the polymer concentration in the freeze-drying solution. The freezing temperature also has an effect on the final morphology of the porous structures. Compared with freeze-drying and combination of freeze-drying /particulate leaching techniques, this method facilitates higher interconnectivity of the scaffolds. Porous structures have been prepared from several relevant polymers in the biomedical and tissue-engineering field: poly(D,L-lactide) (PDLLA), 1000PEOT70PBT30, a segmented poly(ether ester) based on polyethylene oxide and polybutylene terephthalate, and poly(epsilon-caprolactone) (PCL). The mechanical properties of the porous structures prepared by this technique depend on the nature of the polymer, porosity, and the freezing temperature. With porosities in the range of 95-97%, the compression moduli of scaffolds prepared from the different polymers could be varied between 13.0 and 301.5 kPa.     

Porous hydroxyapatite/gelatine scaffolds with ice-designed channel-like porosity for biomedical applications

A cryogenic process, including freeze-casting and drying has been performed to obtain hydroxyapatite (HA) scaffolds (approx. diameter 10 mm, height 20 mm) with completely lamellar morphology due to preferentially aligned channel-like pores. Changing the process parameters that influence the cold transmission efficiency from the bottom to the top of the poured HA slurry, lamellar ice crystals with different thickness grew throughout the samples. After sintering, scaffolds with porosity features nearly resembling the ice ones were obtained. The interconnection of pores and the ability of the scaffolds to be rapidly penetrated by synthetic body fluid has been proven. Biohybrid HA/gel composites were prepared, infiltrating HA lamellar scaffolds (45-55 vol.% of porosity) with a 10wt.% solution of gelatine. Colouring genipine was used to cross-link gelatine and clearly show the distribution of the protein in the composite. The compressive mechanical properties of lamellar scaffolds improved with the addition of gelatine: the strength increased up to 5-6 times, while the elastic modulus and strain approximately doubled. The effectiveness of the cross-linkage has been preliminarily verified following scaffold degradation in synthetic body fluid.     

Fabrication and characterization of porous alginate/polyvinyl alcohol hybrid scaffolds for 3D cell culture

Porous alginate/polyvinyl alcohol (PVA) hybrid scaffolds as bioartificial cell scaffolds were fabricated to improve cell compatibility as well as flexibility of the scaffolds. The alginate/PVA hybrid scaffolds with different PVA compositions up to 50 wt% were fabricated by a modified freeze-drying method including the physical cross-linking of PVA and the following chemical cross-linking of alginate. The prepared alginate/PVA hybrid scaffolds were characterized by morphology observations using scanning electron microscopy (SEM), the measurements of porosity and average pore sizes and the measurements of compressive strength and modulus. The scaffolds exhibited highly porous, open-cellular pore structures with almost the same surface and cross-sectional porosities (total porosities about 85%, regardless of PVA composition) and the pore sizes from about 290 microm to about 190 microm with increasing PVA composition. The alginate/PVA hybrid scaffolds were more soft and elastic than the control alginate scaffold without significant changes of mechanical strength. The scaffolds were examined for their in vitro cell compatibility by the culture of chondrocytes (human chondrocyte cell line) in the scaffolds and the following analyses by MTT assay and SEM observation. It was observed that the alginate/PVA scaffolds had better cell adhesion and faster growth than the control alginate scaffold. It seems that 30 wt% addition of PVA to alginate in the fabrication of the hybrid scaffolds is desirable for improving their flexibility and cell compatibility.     

Effects of porosity and pore size on in vitro degradation of three-dimensional porous poly(D,L-lactide-co-glycolide) scaffolds for tissue engineering

In vitro degradation of seven three-dimensional porous scaffolds composed of PLGA85/15, a very useful poly(D,L-lactide-co-glycolide), was performed in phosphate-buffered saline solution at 37 degrees C up to 26 weeks, and effects of porosity (80-95%) and pore size (50-450 mum) on the degradation of the scaffolds were investigated. A series of quantities were measured during the degradation processes: molecular weight and its distribution of PLGA; compressive strength and modulus; and weight, dimension, and porosity of scaffolds. In all of cases with different pore morphologies, the degradation processes obeyed a three-stage model. Scaffolds with a higher porosity or a smaller pore size degraded more slowly than and thus outlasted those with a lower porosity or a larger pore size. The effects are both attributed to a wall effect and a surface area effect because the scaffolds with lower porosities or larger pores possess thicker pore walls and smaller surface area, which depress the diffusion of acidic degradation products and thus results in a stronger acid-catalyzed hydrolysis. This work suggests that, in designing a tissue-engineering scaffold composed of PLGA and adjusting its degradation rate, the effects of pore morphologies should be taken into consideration in addition to those of chemical composition and condensed state of raw materials.     

Fabrication of porous polysaccharide-based scaffolds using a combined freeze-drying/cross-linking process

Biocompatible three-dimensional (3-D) porous scaffolds are of great interest for tissue engineering applications. We here present a novel combined freeze-drying/cross-linking process to prepare porous polysaccharide-based scaffolds. This process does not require an organic solvent or porogen agent. We unexpectedly found that cross-linking of biomacromolecules such as pullulan and dextran with sodium trimetaphosphate could be performed during freeze-drying. We have demonstrated that the freeze-drying pressure modulates the degree of porosity. High freeze-drying pressure scaffolds presented pores with a mean diameter of 55 ± 4 μm and a porosity of 33 ± 12%, whereas low freeze-drying pressure scaffolds contained larger pores with a mean diameter of 243 ± 14 μm and a porosity of 68 ± 3%. Porous scaffolds of the desired shape could be easily obtained and were stable in culture medium for weeks. In vitro viable mesenchymal stem cells were found associated with porous scaffolds in higher proportions than with non-porous scaffolds. Moreover, cells penetrated deeper into scaffolds with larger pores. This novel combined freeze-drying/cross-linking processing of polysaccharides enabled the fabrication of biocompatible scaffolds with controlled porosity and architectures suitable for 3-D in vitro culture and biomedical applications.     

Fabrication and Characterization of Waterborne Biodegradable Polyurethanes 3-Dimensional Porous Scaffolds for Vascular Tissue Engineering

In this study, a series of 3-D interconnected porous scaffolds with various pore diameters and porosities was fabricated by freeze-drying with non-toxic biodegradable waterborne polyurethane (WBPU) emulsions of different concentration. The structures of these porous scaffolds were characterized by scanning electron microscopy (SEM), and the pore diameters were calculated using CIAS 3.0 software. The pores obtained were 3-D interconnected in the scaffolds. The scaffolds obtained at different pre-freeze temperatures showed a pore diameter ranging from 2.8 to 99.9 μm with a pre-freezing temperature of ?60°C and from 13.1 to 229.1 μm with a pre-freezing temperature of ?25°C. The scaffolds fabricated with WBPU emulsions of different concentration at the same pre-freezing temperature (?25°C) had pores with mean pore diameter between 90.8 and 39.6 μm and porosity between 92.0 and 80.0%, depending on the emulsion concentration. The effect of porous structure of the scaffolds on adhesion and proliferation of human umbilical vein endothelial cells (HUVECs) cultured in vitro was evaluated using the MTT assay and environmental scanning electron microscopy (ESEM). It was found that the better adhesion and proliferation of HUVECs on 3-D scaffolds of WBPU with relative smaller pore diameter and lower porosity than those on scaffolds with larger pore and higher porosity and film. Our work suggests that fabricating a scaffold with controllable pore diameter and porosity could be a good method to be used in tissue-engineering applications to obtain carriers for cell culture in vitro.     

Fabrication and characterization of novel nano hydroxyapatite/β-tricalcium phosphate scaffolds in three different composition ratios

The biphasic calcium phosphate (BCP) concept was introduced to overcome disadvantages of single phase biomaterials. Different composition ratios of BCP bioceramics have been studied, yet controversies regarding the effects of ratio on biomaterial behavior still exist. In this study, BCP scaffolds were prepared from nano hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) that were synthesized via a solid state reaction. Three different composition ratios of pure BCP and collagen-based BCP scaffolds (%HA/%β-TCP; 30/70, 40/60, and 50/50) were produced using a polymeric sponge method. Physical and mechanical properties of all materials and scaffolds were investigated. SEM showed overall distribution of both macropores (80-200 μm) and micropores (0.5-2 μm) with high interconnected porosities. Total porosity of pure BCP (90% ± 3%) was found to be higher than collagen-based BCP (85% ± 2%). It was observed that following sintering process, dimensional shrinkage of large scaffolds (39% ± 4%) was lower than small ones (42% ± 5%) and scaffolds with high HA ratios (50%) experienced higher dimensional changes than those with higher β-TCP (70%) ratios (45% ± 3% and 36% ± 1%, respectively). Compressive strength of both groups was less than 0.1 MPa and collagen coating had almost no influence on mechanical behavior. Further studies may improve the physical properties of these scaffolds and investigate their exact biological behaviors.     

Sugar-mediated chitosan/poly(ethylene glycol)-beta-dicalcium pyrophosphate composite: mechanical and microstructural properties

The microstructural and mechanical properties of sugar-mediated chitosan/poly(ethylene glycol)-based scaffolds and composites, which are composed of beta-dicalcium pyrophosphate (beta-DCP) and sugar-mediated scaffolds, were investigated. All of the scaffolds were prepared by various freeze-drying protocols. The differences in the freeze-drying process of the sugar-mediated chitosan/poly(ethylene glycol) scaffold for three types of sugar (sucrose, glucose, and D-fructose) were determined by scanning electron microscopic observation, water retention, density, and porosity analyses. The sugar-mediated scaffolds prepared by scheme I of the freeze-drying process show large pores, poorly connective interlayers, and disintegrated inner structures, different from the small pores and well-connective channel structures as shown in the scheme II freeze-drying process. The key factors for controlling pore structure and size in the scheme I freeze-drying process were formulation and composition, but for the scheme II freeze-drying process, the key factor was freeze protocol. The composite scaffolds were macroporous, and the microstructure changed considerably with added beta-DCP content. The incorporation of beta-DCP granules caused a significant enhancement of compressive modulus and yield strength. The increased mechanical strength may be attributable not only to the physical complexation between the sugar-mediated scaffold and beta-DCP, but also the chemical reaction to apatite formed on the cell wall.     

3D打印技术制备β-磷酸三钙仿生骨支架在兔股骨髁部骨缺损修复中的应用

目的 探讨采用3D打印技术制备的β-磷酸三钙(β-TCP)仿生骨支架的形态结构特点及其相关生物性能,并观察其修复新西兰兔股骨髁部骨缺损的效果。方法 选取5～6月龄新西兰大白兔20只,随机分为支架组和空白组,每组10只;两组大白兔按造模术后采集标本的时间不同又分为两个亚组,每组5只。两组大白兔均于左侧股骨用环钻钻取直径约5 mm、长约10 mm的圆柱形松质骨块,建立股骨髁骨缺损模型。空白组截取的10个松质骨标本,使用微计算机断层扫描技术进行扫描,获得骨缺损标本的结构影像学数据,通过3D生物打印系统设计出相应的仿生骨支架模型,再以β-TCP作为打印材料,打印出20枚仿生骨支架。取10枚β-TCP支架测量高度、直径,电子显微镜下观察β-TCP支架孔道形态结构特点,测量大孔的直径和孔隙率,使用电子力学测试机测定β-TCP支架的弹性模量与抗压强度。空白组10只大白兔造模后不植入任何材料。支架组10只大白兔在造模后,将制备的10枚β-TCP支架植入骨缺损处。分别于术后第6、12周使用耳缘静脉推注空气方法处死空白组和支架组的各亚组大白兔,于骨缺损部位或植骨部位上下离断、截取长约10 mm骨段,制备切片,HE染色,观察骨组织生长情况;采用Lane-Sandhu组织学评分标准对骨组织修复情况进行评价。结果 使用3D生物打印技术制备的20枚圆柱体β-TCP支架,与松质骨标本结构形态相似。支架高度(9.97±0.08)mm、直径(5.09±0.07)mm,松质骨标本高度(9.96±0.39)mm、直径(5.01±0.22)mm,支架与松质骨标本比较差异均无统计学意义(P值均＞0.05)。扫描电镜观察到支架表面及内部呈均匀多孔状,孔径相互连通,大小相仿,孔隙分布较均匀,在大孔侧壁布满了微孔,外形多为近似圆形;其中大孔直径为(223.02±18.20)μm,孔隙率为74.02%±1.38%。松质骨标本大孔直径(227.02±31.20)μm,孔隙率为76.02%±3.29%,支架与松质骨标本比较差异均无统计学意义(P值均＞0.05)。使用电子力学测试机测定支架的抗压强度为(2.93±0.65)MPa,弹性模量为95～190 MPa。骨组织切片HE染色:术后第6周,支架组植骨处可见较成熟的骨组织,骨小梁和骨髓组织增多,新生骨正在逐渐覆盖植骨材料,周围可见少量成骨细胞,出现少量新生骨并向材料内长入;空白组的骨缺损处周围有少量类骨组织形成,大量成纤维细胞和脂肪组织生长,未见明显成骨细胞及骨小梁结构。术后12周,支架组植骨处出现成熟的骨小梁和骨髓组织,有编织骨形成,新生骨量较多,部分材料已被吸收降解,材料存留较少;空白组的骨缺损处见少量骨组织从缺损边缘向内长入,大部分被成纤维细胞和脂肪组织填充。Lane-Sandhu组织学评分,术后6周、12周支架组分别为(5.2±0.3)、(8.1±1.2)分,空白组分别为(1.3±0.5)、(4.5±0.6)分,支架组评分均大于空白组,差异有统计学意义(t=7.341、12.672, P值均＜0.05)。结论 3D生物打印技术制备的β-TCP仿生骨支架,与松质骨标本的骨组织解剖结构形态相似,且具有良好的生物力学性能,可以提供个体化的仿生骨支架,修复新西兰兔股骨髁部骨缺损的效果良好。     

多孔聚乙烯醇/明胶软骨组织工程支架复合材料的制备及其生物相容性

背景：以明胶为基体制备的组织工程支架材料具有良好的生物相容性和生物降解性能,但存在力学性能低,降解速率难以控制的缺陷。 目的：制备一种软骨组织工程支架材料多孔聚乙烯醇/明胶复合物,并检测其理化性能和生物相容性。 方法：采用乳化发泡法制备聚乙烯醇/明胶多孔支架,并通过电镜分析、力学测试、皮下植入实验,检测材料孔径和孔隙率、IR光谱、力学性能和生物相容性。 结果与结论：多孔材料内部呈三维网状多孔结构,孔径均匀,有相似的孔隙率61.8%,含水率44.6%,抗拉强度为(5.01±0.03) MPa,抗压强度为(1.47±0.36) MPa,有较好的力学性能,IR光谱分析表明材料内部结构均匀。皮下植入后,炎症反应逐渐减轻,囊壁逐渐变薄,并趋于稳定,提示多孔聚乙烯醇/明胶支架材料具有较好的生物相容性和力学性能。