纳米羟基磷灰石/聚酰胺多孔支架材料的制备及其结晶行为研究

以NaCl为致孔剂,采用粒子沥滤-相转移法制备了纳米羟基磷灰石/聚酰胺6(n-HA/PA6)多孔支架材料,用扫描电子显微镜(SEM),X射线衍射(XRD),示差扫描量热仪(DSC)等对其进行表征.结果表明,用该方法制备的多孔支架孔径分布在50～300μm,孔隙率约为77%,孔与孔之间的贯通性良好.用粒子沥滤-相转移法制备的支架中PA6的晶胞体积较制备前有所增大,同时其结晶度也有增加.研究表明,NaCl粒子的存在促进了PA6聚合物晶体的生长.在制备成支架后,n-HA/PA6复合材料中PA6仍为混晶型高聚物,其晶型部分发生了转变,由制备前α晶型占多数变成了制备后γ晶型占多数.支架的制备过程使PA6更容易结晶,但结晶总速率在制备支架前后均没有太大改变.     

纳米羟基磷灰石／聚氨酯复合材料的制备与表征

以模拟体液（SBF）为介质,采用仿生法制备了纳米羟基磷灰石（n-HA）,通过原位聚合法制备了纳米羟基磷灰石／聚氨酯（n-HA／PU）复合材料。利用x射线衍射（XRD）、红外光谱（FT-IR）、热重分析（TGA）、扫描电镜（SEM）研究了n—HA和复合材料的结构和热稳定性、表面形貌特征。结果表明,在SBF中用浓度为0．200mol／L硝酸钙溶液制备出具有良好结晶度的n-HA,由此制备的n—HA／PU复合材料开孔率良好,有望成为一种性能良好的医用组织支架材料。     

3D PLLA/nano-hydroxyapatite scaffolds with hierarchical porous structure fabricated by low-temperature deposition manufacturing

A new Precision Extrusion nozzle based ball screw transmission was developed.3D hierarchical porous PLLA/nano-Hydroxyapatite(PLLA/nHA)scaffolds were fabricated by low-temperature deposition manufacturing.Scaffolds with macropores of 200-500 μm and micropores about 10 μm were fabricated through a thorough study and control of the processing parameters,in which the processing path and speed of material extrusion determine the macropores and there is a suitable temperature zone for fabricating qualified macropores.Micropore morphology can be controlled by adjusting supercooling of solvent crystallization or adding water into the solvent system.The compressive modulus of the scaffolds in air and phosphate buffer solution was measured,which increased with HA addition.In-vitro cell culture results showed a good biocompatibility of PLLA/HA scaffolds with the pre-osteoblastic MC3T3-E1 cells.     

纳米羟基磷灰石/丝素蛋白/聚己内酯复合超细纤维的制备及表征

通过静电纺丝法制备出纳米羟基磷灰石/丝素蛋白/聚己内酯复合超细纤维,利用扫描电镜、红外光谱仪、X射线衍射仪对纳米羟基磷灰石/丝素蛋白/聚己内酯复合超细纤维形貌和结构进行表征,并进行了拉伸测试。结果表明,随着超细纤维中羟基磷灰石含量的增加,纤维的直径逐渐降低,纤维中聚己内酯的结晶逐渐变差。相比于丝素蛋白/聚己内酯超细纤维,含有质量比为30%羟基磷灰石的复合超细纤维仍具有较好的力学性能。体外小鼠成纤维细胞(L929)培养表明,纳米羟基磷灰石/丝素蛋白/聚己内酯复合超细纤维对细胞没有毒性。     

玉米醇溶蛋白/明胶/羟基磷灰石纳米纤维膜制备及其性质研究

本研究通过静电纺丝技术制备了玉米醇溶蛋白/明胶/纳米羟基磷灰石（nHAP）复合纳米纤维膜。通过旋转测试和振荡测试发现玉米醇溶蛋白/明胶/纳米羟基磷灰石溶液为剪切变稀非牛顿流体并且具有粘弹性。纳米羟基磷灰石的添加显著增加了玉米醇溶蛋白/明胶（3/1,w/w）纳米纤维的直径,但不同nHAP浓度的纳米纤维之间没有显著差异。高浓度nHAP的复合纳米纤维中观察到结节的形成,通过TEM观察发现nHAP在纤维内部和表面均有分布。红外光谱结果表明蛋白与nHAP之间通过氢键相互作用,当nHAP添加浓度为10%时引起了蛋白二级结构从β-折叠向转角结构的转变。玉米醇溶蛋白/明胶/纳米羟基磷灰石复合纳米纤维膜表现出疏水的表面,随着10%nHAP的加入疏水性有所增加,这是由于表面极性基团比例的下降。由于高浓度的nHAP在纤维中聚集导致其对纳米纤维膜的机械性能产生了不利影响。     

增强型聚乳酸纳米纤维复合支架的制备与表征

采用热致相分离法制备了纳米羟基磷灰石和壳聚糖纤维增强的聚乳酸复合支架。扫描电镜结果显示复合支架具有纳米纤维和微米孔隙共存的亚微观结构形态,利于细胞生长。孔隙率测定结果显示复合支架的孔隙率较高(>88%),满足组织工程用要求。力学性能测定结果显示复合支架的压缩模量有显著增加,与纯聚乳酸支架相比,复合支架压缩模量的最大值能增加2~3倍。     

纳米羟基磷灰石/壳聚糖-明胶复合支架材料缓释基因的研究

用冷冻干燥法制备不同比例的纳米羟基磷灰石/壳聚糖-明胶(n-HA/CS-Gel)三维多孔支架材料,加入含骨形态发生蛋白-2(BMP-2)基因的质粒后再次冷冻干燥,制成具有基因缓释功能的组织工程支架材料.对支架材料的形貌结构、力学性能、体外降解特性、质粒的体外释放特性及质粒完整性进行检测.结果显示:纳米羟基磷灰石均匀分散在支架材料中,随着其含量的增加,孔隙率减少,抗压强度提高,在体外降解速度减慢.质粒DNA在体外1～3d快速释放,并能够维持释放5周以上,随着纳米羟基磷灰石含量的增加,释放时间延长,释放出的质粒DNA能够保持完整性.具有基因缓释功能的n-HA/CS-Gel支架材料是一种有望用于临床的新型骨组织工程支架材料.     

纳米羟基磷灰石/天然胶乳复合乳胶膜的制备及性能表征

对比研究了纳米羟基磷灰石(n-HA)经硅烷偶联剂(KH-570)表面改性前后的性能变化,实验结果表明,n-HA经改性后,疏水性得到提高,其表面与KH-570发生了偶联作用(FT-IR);将改性的n-HA与天然胶乳复合制备复合乳胶膜,力学性能测定结果表明,复合乳胶膜的力学强度与未经处理的相比有一定提高;另外n-HA还能够有效的抑制复合乳胶膜中水溶性蛋白的析出,利用考马斯亮蓝法测定复合材料中的水溶性蛋白,随着n-HA的添加量的增加,复合乳胶膜中的水溶性蛋白被屏蔽,溶出量逐渐降低。     

Biodegradable chitosan-based composites with dual functions acting as the bone scaffold and the inflammation inhibitor in the treatment of bone defects

A composite based on nano-hydroxyapatite (n-HA)/chitosan (CS) and loaded with ciprofloxacin (CIP) was prepared and its physicochemical properties, antibacterial properties, drug release ability, and bone regeneration ability were characterized. The physicochemical results indicated that the n-HA/CS composite exhibited about a 70/30 ratio of n-HA to CS, and the size of n-HA in the n-HA/CS composite was about 100?nm. According to the results of the antibacterial test, the materials loaded with CIP presented excellent antibacterial activity. In addition, the in vivo concentration of CIP far surpassed the minimum inhibitory concentration (0.25–2?µg?mL^?1). In vitro standard deviation-rats marrow mesenchymal stem cells (MSCs) tests, including cell counting kit-8 assay and scanning electron microscopy images of MSCs, revealed that both of the scaffolds could support MSCs proliferation and attachment. The in vivo results indicated that n-HA/CS-CIP could promote the formation of bone tissues and blood vessels, and displayed a better repair ability for bone defect than the control group of n-HA-CIP. The CS-based composite with dual functions has a good perspective which would justify further research.     

用超声分散法和研磨法制备纳米羟基磷灰石/聚酯型弹性体复合材料的比较

分别用超声分散法和研磨法制备了纳米羟基磷灰石(n-HA)/聚1,2-丙二醇-癸二酸-柠檬酸酯复合材料。通过差示扫描量热法、扫描电子显微镜和透射电子显微镜对复合材料中n-HA的分散性及复合材料的玻璃化转变温度进行了分析,测试了复合材料的溶胶含量、力学性能及降解性能。结果表明,无论是采用研磨法还是超声分散法制备的复合材料,其玻璃化转变温度和溶胶含量都随着n-HA质量分数的增加而降低,降解速率都随着n-HA质量分数的增加而减小。研磨法是改善n-HA在复合材料中的分散性、提高复合材料力学性能的有效方法。用该方法通过改变n-HA质量分数可使复合材料的拉伸强度提高8.2倍,弹性模量提高11.4倍,而扯断伸长率基本保持不变。