明胶/丝素共混多孔膜的制备

采用冷冻干燥法制备明胶与家蚕丝素的共混多孔蛋白膜，探讨了交联剂用量，共混比例及冷冻温度对膜结构和性能的影响，指出戊二醛对共混多膜具有明显的交联作用，膜内丝素与明胶的相容性较好，蛋白质的结构以无定形为主，通过与明胶共混，能够改善多孔丝素膜的拉伸性能。     

壳聚糖多孔支架的制备与生物学性质

用一种蛋白改性壳聚糖,通过冷冻干燥方法制备三维多孔支架,对支架材料的细胞毒性、贴壁率和细胞增殖等生物学特性进行评价.结果显示,采用-20,-70,-196 ℃不同温度预冻后冻干,可以制成孔结构不同的支架材料.通过冻干法制备的蛋白改性壳聚糖多孔支架对细胞没有毒性,L929细胞和人成纤维细胞可以在支架表面和内部正常生长和增殖,角质细胞在材料表面可以正常老化、角质化.     

聚乳酸多孔支架的制备研究

分别采用粒子滤出法和冷冻干燥粒子滤出复合法制备了聚乳酸多孔支架.在粒子滤出法中,采用氯化钠和碳酸氢铵作为造孔剂制备多孔支架;在冷冻干燥法中,采用碳酸氢铵和冰颗粒作为造孔剂制备多孔支架.实验结果表明:采用氯化钠或碳酸氢铵做造孔剂,生成的多孔支架有造孔剂残留;采用冰颗粒造孔则无残留.研究认为,采取适当的工艺措施,加速造孔剂向环境的传质过程,是降低支架中造孔剂残留的有效途径,并提出了在实际中可采取的改进措施,包括选用易于滤出的材料、提高氯仿和造孔剂含量、提高温度和真空度、采用特殊气氛、提高过滤溶液的流动性.     

多孔柞蚕丝素支架的制备及其在药物缓释中的应用

采用冷冻干燥法制备了多孔柞蚕丝素支架,分析了丝素溶液浓度与支架孔径、孔隙率之间的关系,并研究了多孔柞蚕丝素支架负载5-氟尿嘧啶的缓释性能.研究表明,当丝素浓度较低时,支架中的孔洞分布较为均匀,孔径和孔隙率也较大,而随着丝素溶液浓度增大,支架的孔径和孔隙率逐渐减小;支架的药物释放过程可分为快速释放和缓慢释放两个阶段.     

Preparation of insoluble fibroin films and its tensile property

Silk fibroin is becoming a promising biomate-rial because of its excellent biocompatibility. However, theregenerated fibroin is usually soluble in water and its me-chanical properties should be improved. Although manymethods, such as adding other polymers or treating withmethanol, can ameliorate the mechanical properties andinsolubility, the biocompatibility of fibroin is usually dam-aged in these processes. In this article, it is first reported thatthe insoluble fibroin films are directly prepared withoutmethanol treatment. According to the results of Fouriertransform infrared spectroscope (FTIR) and the X-ray dif-fraction (XRD), the amount of IS-sheet conformation in-creased with the increasing of concentration. When fibroinfilms are dried from 15 wt% at 60℃, the films become in-soluble in water. More importantly, The tensile strength andelongation of the insoluble fibroin films dried from 15% so-lution at 60℃ reached 15.9 MPa and 49.4% respectively in the wet state, which is distinctly superior to the fibroin films treated with methanol.     

天然丝素制备三维多孔支架

研究盐沥滤法制备三维多孔丝素支架,在丝素多孔支架上培养人成骨肉瘤细胞、成纤维细胞及肝细胞.研究材料的细胞相容性,发现多种动物细胞在盐沥滤法所制备的丝素多孔支架材料上能够很好地黏附和增殖.通过调整丝素水溶液的浓度、溶解丝素溶剂体系、NaCl添加量和NaCl粒径,制备出结构和性质可以调控的三维支架.该结果为丝素多孔支架材料的制备提供了新的研究思路和方法.     

Fine Structure of Regenerated Silk Fibroin Solids

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三维微流道支架直接压印成形方法

针对软质生物材料支架内部三维微结构成形难题,提出了结合分层制造、微压印与冷冻干燥技术的三维微流道支架直接压印成形方法.通过开发自动化成形设备,实现了材料溶液填充、微结构压印、结构预冻、层间黏结等工艺过程的可控化,从而解决了传统手工操作所造成的结构重复性差、成形效率低等问题.研究了模具表面等离子处理、亲水物质添加、改变溶液填充方式等工艺对自动化成形过程中微结构复型性能的影响.结果表明,向材料溶液中添加微量亲水物质并辅助溶液填充引导,可实现软质水溶性天然生物材料内部复杂微流道结构的精确三维压印成形.通过工艺装备保证了成形过程的自动化和稳定性,从而实现了支架微结构制造的可重复性与可控性.     

Fabrication and Properties of Porous Film/Fabric Composites for Vascular Scaffold Application

A composite vascular scaffold combining textile reinforced structure and biodegradable polymer is introduced, which may possess high porosity and connectivity. Moreover, the porous size could be controlled. The proposed scaffold consists of a warp-knitted poly （ethylene terephthalate ） （PET） fabric with well-defined macropores, which is embedded with a porous biodegradable polymer membrane. The aim of this paper is to study the fabrication and properties of porous polymer membrane through optimizing the parameter of composite methods from freeze drying/particle leaching （ FD/PL ） and gas foaming/particle leaching （ GF/PL ）, subsequently combining with the warp-knitted fabric. Weighing method was utilized to analyze the porosity of the samples and the scanning electron microscope （SEM） images were taken to observe the porous structure of the vascular membrane. In addition, ,the static contact angle （CA） was measured to estimate the hydrophilicity of the samples, and the tensile testing of the composites was performed on the universal mechanical tester. Furthermore, the water permeability of the membrane was also calculated. The results showed that the porosity and pore connectivity of the vascular membrane were diverse, became of solution concentration, particle size, ratio of content, etc. Meanwhile, the stress-strain curves and the bursting strength showed the different mechanical properties among composite scaffolds in different structures.     

Preparation and Characterization of Silk Fibroin Aerogel

Silk protein fibroin,as a biomedical material,has good biocompatibility,biodegradability,regulation and excellent physical and chemical properties. In this work,a low density porous silk fibroin material is prepared from fibroin solution by high-speed shearing with impeller. By adjusting shear rate of the stirrer,silk fibroin aerogel with different sizes of the aperture is prepared. In general, this aerogel has small porosity, uniform pores, good mechanical properties and slow rate of degradation. It is observed that increasing the shear rate results in higher porosity of aerogel,while the diameter of the aerogel becomes smaller. This silk aerogel may offer a new option as biomaterial for the tissue engineering application based on the information on the structural behaviors.     

3D Nanocomposite Hydrogel Scaffolds Fabricated by Rapid Prototyping for Bone Tissue Engineering

Colloidal gels made of oppositely charged nanoparticles are a novel class of hydrogels and can exhibit pseudoplastic behavior which will enable them to mold easily into specific shapes. These moldable gels can be used as building blocks to self-assemble into integral scaffolds from bottom to up through electrostatic forces. However, they are too weak to maintain scaffold morphology just depending on interparticle interactions such as Van der Waals attraction and electrostatic forces especially for bone tissue engineering. In this study, oppositely charged gelatin nanoparticles were firstly prepared by two-step desolvation method, followed by the mixture with water to form colloid gels. To solve the problem of weak mechanical performance of colloid gels, gelatin macromolecules were introduced into the prepared gels to form blend gels. The blend gels can be easily processed into three-dimensional （3D） porous scaffolds via motor assisted microsyringe （MAM） system, a nozzle-based rapid prototyping technology, under mild conditions. After fabrication the scaffolds were erosslinked by glutaraldehyde （ GA, 25 % solution in water by weight）, then the crosslinked gelatin macromolecules network could form to improve the mechanical properties of colloid gels. The average particle size and zeta potential of gdatin nanoparticles were measured by Nano- ZS instrument. The morphology and microstructures of scaffolds were characterized by macroscopic images. The mechanical properties of the scaffolds were studied by a universal material testing machine.     

非挥发性组分对真空冷冻干燥过程的影响

对纯水和ＮａＣｌ溶液在砂床中冷冻干燥的特性进行了实验研究,分析了冻干过程中砂床温度的分布特性,研究了在不同颗粒尺寸砂床中,溶液浓度对干燥时间的影响和干燥后非挥发性质砂床中的分布。     

On Modeling Bio-Scaffolds: Structural and Fluid Transport Characterization Based on 3-D Imaging Data

Bio-scaffolds which are most commonly open celled porous structures are increasingly used for tissue engineering and regenerative medicine. A number of studies have shown that the bulk properties of such irregular structures are poorly modeled using idealized unit cell approaches. The paper therefore uses novel image based meshing techniques to explore both fluid flow and bulk structural properties of a bone scaffold, as accurate modeling of bio-scaffolds with non-uniform cellular structures is very important for the development of optimal scaffolds for tissue engineering application. In this study, a porous hydroxyapatite/tricalcium phosphate (HA/TCP) bone scaffold has been scanned in a Micro-CT scanner, and converted into a volumetric mesh using image processing software developed by the authors. The resulting mesh was then exported to commercial FEA and CFD solvers for analysis. Initial FEA and CFD studies have shown promising results and have highlighted the importance of accurate modeling to understand how microstructures influence the mechanical property of the scaffold, and to analyze flow regimes through the sample. The work highlights the potential use of image based meshing for the ad hoc characterization of scaffolds as well as for assisting in the design of scaffolds with tailored strength, stiffness, and transport properties.     

Structure and Property of Silk Fibroin ／ Cellulose Blend Film

Silk fibroin/cellulose blend films were prepared using Nmethylmorpholine-N-oxide (NMMO) as solvent. The effects of different proportions and solid contents on properties of blend films were discussed. The mechanical properties showed that the blend films had preferable moisture permeability and a high strength. The structures of the blend films were investigated by infrared spectrum and X-ray diffraction. The results indicated the occurrence of hydrogen bonds between hydroxyl groups of cellulose and amido groups of fibroin.     

多孔介质快速传热传质藕合效应的理论研究

针对多孔材料快速受热物理过程传热和传质藕合微分方程组,用拉普拉斯变换法进行求解,将温度和湿度藕合方程转化为温度度或湿度的常微分方程,给出了半无限体藕合方程温度或湿度拉氏变换的普遍解。且给出各自普适解系数之间的比例关系。在第一类边界条件下对具体算例进行解析研究,求得问题的解析解,给出了温度和湿度的时空变化规律。讨论了传热与传质过程的藕合效应,结果表明在快速受热情况下,考虑与不考虑藕合效应表面邻域温度和湿度的空间分布差别很大,藕合效应非常明显。     

胶原支架材料的制备与表征

分别采用真空高温脱水和化学交联剂1-乙基-3-(3-二甲基氨基丙基)-碳化二亚胺处理经冷冻干燥后的胶原海绵材料,制备组织工程支架,讨论反应条件对胶原性能的影响,测定胶原支架的力学强度和降解特性.结果发现,不同的处理方法都能保持胶原海绵的三维多孔结构,孔隙率可达到90%;真空高温脱水获得的胶原海绵材料力学强度较小,但断裂伸长率略大;碳化二亚胺交联胶原海绵材料力学强度相对较高,抗张强度为380 kPa左右.胶原海绵交联后,降解速率显著小于未经交联的胶原材料.细胞培养试验表明成纤维细胞可以在支架材料上正常生长.两种交联方法处理胶原海绵,其细胞生长行为差异无显著性,适合于作为组织工程支架.     

氧化碳加氢合成甲醇CuO-ZnO-ZrO2催化剂的制备

采用共沉淀法、真空冷冻干燥法、超声波法、水热法等方法制备了一系列CuO-ZnO-ZrO2甲醇合成催化剂,在微型固定床反应器上考察了其对CO2加氢合成甲醇的催化性能及影响,并用XRD、H2-TPR、CO2-TPD、TEM、EDAX、BET等手段进行了表征.研究结果表明,采用真空冷冻干燥法和超声波法能够制备出高比表面积、高活性、高选择性的甲醇合成催化剂CuO-ZnO-ZrO2     

多孔淀粉的酯化交联改性及其性质研究

以玉米多孔淀粉为原料,三氯氧磷为交联剂制备酯化交联多孔淀粉,利用扫描电子显微镜、布拉班德黏度仪等分析仪器对原淀粉、多孔淀粉和酯化交联多孔淀粉的理化性质、流变学性质、微观结构进行分析比较研究,结果表明,经交联处理后多孔淀粉的吸水率、吸油率与原淀粉相比有较大提高,溶解度、膨胀率、冻融稳定性、耐酸性都有较大改善,优于原淀粉和多孔淀粉,同时也提高了多孔淀粉的结构性能.     

几种骨组织工程复合支架材料在模拟生理溶液中的生物矿化性能比较

采用生物活性玻璃(BG)、磷酸三钙(TCP)、羟基磷灰石(HA)等生物活性陶瓷与3-羟基丁酸酯-3-羟基戊酸酯的共聚物(PHBV)复合,制备了性能良好的骨组织工程支架材料,分析了PHBV/BG,PHBV/TCP,PHBV/HA三种复合多孔支架在模拟生理溶液中的一系列化学反应,以及多孔材料在模拟生理溶液中浸泡后的成分、结构和微观形貌的变化.研究结果表明,三种复合支架材料在模拟生理溶液中发生了降解反应而失重;PHBV/BG和PHBV/TCP在模拟生理溶液中还发生了生物矿化反应,在表面形成矿化沉积层,为具有骨生物活性的结晶态类骨碳酸羟基磷灰石;而PHBV/HA在模拟生理溶液中没有明显的生物活性反应.     

聚合诱导相分离法制备纳米Fe掺杂多孔炭

以2130酚醛树脂为碳质前驱体,乙二醇为溶剂,苯磺酰氯为催化剂,纳米单质Fe粒子为掺杂剂,通过聚合诱导相分离热解法制备了掺Fe多孔炭单体,主要分析了Fe对前驱体溶液和多孔炭形态的影响。结果表明:纳米Fe粒子使前驱体溶液的pH值降低,溶液开始凝胶的时间增长,不同酚醛树脂含量下纳米Fe掺杂多孔炭的微结构及性能具有明显差异。Fe主要化合态存在于FeS和C48H44Fe14.01N15O35.68中。