壳聚糖/羟基磷灰石表面修饰聚己内酯多孔骨支架的制备及性能

采用选择性激光烧结技术构建多孔聚己内酯(PCL)骨支架,用原位合成的方法制得壳聚糖/羟基磷灰石(CS/HA)悬浮液,并采用真空浸泡、低速离心和冷冻凝胶的方法使CS/HA黏附在PCL支架的表面,以改善骨支架的生物相容性和细胞增殖活性。通过X射线衍射(XRD)和扫描电子显微镜(SEM)观测复合支架的物相和形貌,测量支架的压缩强度和杨氏模量,测量支架表面的水接触角,并通过体外细胞实验研究复合支架的生物学性能。实验结果表明,原位合成的方法制得了羟基磷灰石(HA);CS/HA凝胶与PCL骨支架表面黏附良好;CS/HA改善了PCL支架表面的亲水性,提升了骨支架的生物相容性和细胞增殖活性。     

羟基磷灰石基多孔复合支架的制备及其表征

研究利用造孔剂法制备高度贯通的多孔羟基磷灰石(HA)支架,孔隙率约为78%,并利用聚己内酯(PCL)分别复合纳米HA(nHA)或微纳米生物玻璃(nBG)粉末对其进行涂覆改性,粉末的添加量均为10%~40%(质量分数)。4种类型支架分别记为HA、PCL/HA、nHA-PCL/HA和nBG-PCL/HA。实验结果发现,nHA-PCL/HA和nBG-PCL/HA复合支架最大抗压强度分别为1.41~1.98 MPa和1.35~1.78MPa。4类支架矿化实验显示,浸泡21d后nBG-PCL/HA表面促进生成较多的磷灰石矿化物;细胞实验结果显示细胞在4类支架上均生长良好,说明支架具有良好的生物相容性。支架在实验犬背部肌肉组织内植入2个月的组织学检测显示,4种支架内均有新骨形成,尤其是nHA-PCL/HA和nBG-PCL/HA孔内有更多的新生骨组织,说明这两种支架表面复合涂层中的生物活性纳米颗粒对诱导新骨生成具有积极的促进作用。     

纤维素/聚醚砜共混物激光烧结弹性性能的分子动力学模拟

为提高选择性激光烧结(SLS)木塑复合粉末的成形件的力学强度,设计出可用于该项技术木塑复合粉末的新配方,制备了纤维素/聚醚砜(PES)和纤维素/聚丙烯(PP) 2种木塑复合粉末。利用分子力学和分子动力学模拟方法对纤维素/PES和纤维素/PP共混物进行共混计算,求得了纤维素分别与PES、PP的结合能分布曲线。通过建立不同质量比的纤维素/PES共混物分子模型,计算其Flory-Huggins相互作用参数和静态弹性性能,得到了纤维素含量对共混物弹性性能的影响;为验证模拟结果进行了纤维素/PES和纤维素/PP共混物的激光烧结实验。结果表明:相比较纤维素/PP复合粉末,纤维素与PES相容性更好,适用于选择性激光烧结技术;当纤维素加入质量分数为20%~25%时,材料的相容性达到最佳状态;所构建的纤维素/PES共混物模型可用于预测成形材料的弹性性能。      

一种新型复合膜层的制备及其性能研究

在镁合金上设计研究出一种增强型生物相容性好耐腐蚀的MgO/PCL/ZnO复合膜层。采用阳极氧化法和浸渍提拉法将AZ91镁合金与聚己内酯(PCL)及粉末ZnO复合制备出该复合生物膜层。对该复合膜层进行了SEM、附着力、电化学、生物浸泡实验等。研究结果表明,该复合生物膜层表面完整,孔隙率低,ZnO在PCL中均匀分布;复合层附着力好;该复合材料具有好的耐腐蚀性能。     

聚己内酯/羟基磷灰石晶须复合多孔支架的研究

采用溶液浇铸法,以二氯甲烷作为溶剂,制备了聚己内酯/羟基磷灰石晶须(PCL/HAw)复合多孔支架,并进行了正交试验,综合分析了不同配方量的PCL和HAw对材料机械性能的影响。结果表明,可通过控制PCL的量来控制支架的力学性能,通过加入HAw提高支架的亲水性能,支架的接触角实验显示其接触角为81°;PCL的结晶度会随着HAw含量的增加而增强,复合多孔支架的抗拉强度为1.43M~9.21MPa,并在PCL与HAw的质量比为100∶3时达到最大;细胞毒性实验显示,PCL/HAw复合多孔支架细胞毒性为0,满足生物材料使用要求。     

纳米羟基磷灰石/聚己内酯复合生物活性多孔支架研究

采用水热法制备了纳米羟基磷灰石（n-HA）及其与聚己内酯（PCL）的复合材料. 用熔融浇铸/食盐微粒浸出法制备了孔径在200～400μｍ、大孔互相贯通的复合材料支架. 通过细胞培养和体内动物实验研究了该支架的生物学性能. 结果表明,复合支架的孔隙率随致孔剂用量的增加而增加,而抗压强度随之而减小;支架的最大孔隙率可达86%,相应的抗压强度为2.4MPa. 成骨细胞在支架上的细胞粘附率和增殖随磷灰石含量增加而提高,复合材料明显高于单纯的PCL支架. 组织学观察显示,新生骨长入多孔支架和复合材料形成了直接的骨性结合. n-HA/PCL复合材料支架有很好的生物相容性和生物活性.     

用于软骨和软骨下骨修复的纳米羟基磷灰石/聚乙烯醇/聚酰胺66功能梯度材料的制备和表征

利用反复冷冻-解冻法和相分离法,制备出用于软骨和软骨下骨修复的纳米羟基磷灰石(nHA)/聚乙烯醇(PVA)/聚酰胺(PA66)功能梯度材料。研究表面层PVA的力学性能和摩擦学性能,及软骨下骨nHA/PA66(m(HA)∶m(PA66)=1∶1)支架的力学性能及生物学性能。结果表明PVA拉伸强度为1.938MPa,平均摩擦系数在生理盐水及代血浆润滑条件下分别为0.076和0.085;nHA/PA66复合多孔支架孔隙率为80.93%,孔径为50～500μm,压缩强度和压缩模量分别为0.88和15.21MPa,且具有良好的生物相容性。     

海藻酸钙水凝胶/聚乳酸复合材料的制备与性能

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。     

激光熔融静电纺丝法制备PLLA/PCL/nHA复合纤维支架及细胞相容性评价

利用激光熔融静电纺丝技术制备了PLLA/PCL及PLLA/PCL/nHA复合纤维,热压后形成层压复合纤维支架。利用扫描电镜对纤维支架进行了表征,同时对其进行了亲水性的测试,最后通过倒置荧光显微镜和MTT实验对复合纤维支架的细胞相容性进行了评价。研究结果表明,层压复合纤维支架的直径和孔结构具有多样性,nHA能够提高PLLA/PCL层压纤维支架的亲水性,改善支架的细胞相容性,增加细胞的附着能力,提高细胞的存活率。     

选择性激光烧结用尼龙12覆膜Cu粉的制备

提出了溶剂沉淀法制备选择性激光烧结(SLS)用尼龙12覆膜Cu粉复合粉末材料,利用扫描电镜(SEM)观察了复合粉末材料的微观形貌,通过差示扫描量热分析(DSC)、热重分析(TGA)对复合粉末材料的熔融、结晶行为,烧结温度窗口及热稳定性进行了研究,并测试了其烧结件的力学性能。结果表明,复合粉末材料的熔点、结晶速度及热稳定性较纯尼龙粉末有所提高,烧结温度窗口变宽,因而烧结性能优于纯尼龙粉。复合粉末材料烧结件的弯曲强度、弯曲模量、硬度均高于纯尼龙粉的烧结件。     

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.     

Preparation of poly(3-hydroxybutyrate)/nano-hydroxyapatite composite scaffolds for bone tissue engineering

Poly(3-hydroxybutyrate)/nano-hydroxyapatite (PHB/nHA) composite scaffolds were fabricated via powder mixing, compression moulding, and particle leaching technique. The scaffolds had high porosity with interconnected porous architecture, a favorable structure for cell attachment and new bone tissue ingrowth. A homogeneous dispersion and a uniform distribution of HA nanoparticles in the polymer matrix were obtained. The scaffolds exhibited improved compressive modulus and compressive strength, which were all in the range of compressive modulus and compressive strength of cancellous bone. In addition, the use of toxic organic solvents was eliminated. Thus, the fabricated PHB/nHA composite scaffolds tend to be promising for application in bone tissue engineering.     

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

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.     

介孔生物活性玻璃/脱钙骨复合支架的制备及性能研究

将介孔生物活性玻璃(MBG)与脱钙骨(DB)复合, 利用浸渍法制备出MBG/DB复合支架材料. 采用红外光谱(FTIR), 扫描电镜(SEM), X射线衍射(XRD), 电子万能材料试验机等方法对牛松质骨(CB)、DB、MBG/DB复合支架进行表征. 结果表明, CB经浸酸处理后制备的DB, 孔径大小在200~600μm范围内, 孔隙率约为71%, 抗压性能比CB明显降低(1.10±0.31)MPa, 而采用浸渍法制备的复合支架, 孔隙率降为40%左右, 而压缩强度明显提高(8.49± 2.14)MPa. 体外生物活性测试表明: 复合支架具有良好的生物活性.     

复合明胶涂层对钙磷陶瓷多孔支架的增强作用

采用有机泡沫浸渍工艺制备了高孔隙率的钙磷多孔陶瓷支架, 将多孔陶瓷样品浸于明胶溶液中渗涂得到陶瓷/明胶复合支架; 采用复合明胶涂层的方法对钙磷多孔陶瓷支架进行增强处理, 在不破坏多孔支架孔隙特征的情况下, 成功地在样品的孔壁上复合了明胶涂层。复合明胶涂层提高了样品的压缩强度和压缩模量, 与未涂覆样品相比, 涂敷样品受压时的应变特性发生了明显变化。尤其是渗涂5%明胶溶液的多孔样品, 在保持高孔隙率(82.8%)的条件下其压缩强度和压缩模量分别由原来的1.04MPa 和 0.105GPa增加到5.17MPa和0.325GPa。研究结果表明, 孔壁上复合明胶涂层可以有效地增强多孔陶瓷支架。      

Biofabrication and in vitro study of hydroxyapatite/mPEG–PCL–mPEG scaffolds for bone tissue engineering using air pressure-aided deposition technology

The aims of this study were to fabricate biopolymer and biocomposite scaffolds for bone tissue engineering by an air pressure-aided deposition system and to carry out osteoblast cell culture tests to validate the biocompatibility of fabricated scaffolds. A mPEG–PCL–mPEG triblock copolymer was synthesized as a biopolymer material. Biocomposite material was composed of synthesized biopolymer and hydroxyapatite (HA) with a mean diameter of 100 μm. The weight ratio of HA added to the synthesized biopolymer was 0.1, 0.25, 0.5 and 1. The experimental results show that the maximum average compressive strength of biocomposite scaffolds, made of weight ratio 0.5, with mean pore size of 410 μm (porosity 81%) is 18.38 MPa which is two times stronger than that of biopolymer scaffolds. Osteoblast cells, MC3T3-E1, were seeded on both types of fabricated scaffolds to validate the biocompatibility using methylthianzol tetrazolium (MTT) assay and cell morphology observation. After 28 days of in vitro culturing, the seeded osteoblasts were well distributed in the interior of both types of scaffolds. Furthermore, MTT experimental results show that the cell viability of the biocomposite scaffold is higher than that of the biopolymer scaffold. This indicates that adding HA into synthesized biopolymer can enhance compressive strength and the proliferation of the osteoblast cell.     

Biocompatibility and biodegradation studies of PCL/β-TCP bone tissue scaffold fabricated by structural porogen method

Three-dimensional printer (3DP) (Z-Corp) is a solid freeform fabrication system capable of generating sub-millimeter physical features required for tissue engineering scaffolds. By using plaster composite materials, 3DP can fabricate a universal porogen which can be injected with a wide range of high melting temperature biomaterials. Here we report results toward the manufacture of either pure polycaprolactone (PCL) or homogeneous composites of 90/10 or 80/20 (w/w) PCL/beta-tricalcium phosphate (β-TCP) by injection molding into plaster composite porogens fabricated by 3DP. The resolution of printed plaster porogens and produced scaffolds was studied by scanning electron microscopy. Cytotoxicity test on scaffold extracts and biocompatibility test on the scaffolds as a matrix supporting murine osteoblast (7F2) and endothelial hybridoma (EAhy 926) cells growth for up to 4?days showed that the porogens removal process had only negligible effects on cell proliferation. The biodegradation tests of pure PCL and PCL/β-TCP composites were performed in DMEM with 10?% (v/v) FBS for up to 6?weeks. The PCL/β-TCP composites show faster degradation rate than that of pure PCL due to the addition of β-TCP, and the strength of 80/20 PCL/β-TCP composite is still suitable for human cancellous bone healing support after 6?weeks degradation. Combining precisely controlled porogen fabrication structure, good biocompatibility, and suitable mechanical properties after biodegradation, PCL/β-TCP scaffolds fabricated by 3DP porogen method provide essential capability for bone tissue engineering.