三维丝素蛋白/羟基磷灰石支架的生物学性能

综合运用丝素蛋白纤维网的非编织制作方法和仿生矿化法,构建三维多孔丝素蛋白/纳米羟基磷灰石复合支架.通过体外蛋白酶降解和成骨细胞培养,对支架材料的生物学性能进行初探.发现蛋白酶对丝素蛋白降解的作用大小依次为,蛋白酶K＞胰蛋白酶＞α-糜蛋白酶＞Ⅰ型胶原酶.所构建的支架显示出良好的生物相容性并能促进成骨细胞生长和分化.三维多孔丝素蛋白/纳米羟基磷灰石支架可望成为新型有机/无机复合生物材料,为骨组织工程支架的设计提供了新的思路.     

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.     

高链玉米淀粉对聚己内酯组织工程支架材料结构与性质的影响

采用高链玉米淀粉改性聚己内酯（PCL）,通过溶剂浇铸/粒子沥滤法制备聚己内酯/淀粉（SPCL）组织工程支架;考察了改性后支架材料的化学结构、结晶性、亲水性和细胞相容性.结果表明,适量淀粉的引入能够降低支架材料的结晶性、改善材料的亲水性和细胞相容性,70％PCL/30％淀粉支架材料的细胞粘附率、增殖率和细胞活性为最佳,有望应用在骨组织工程中.     

改进溶剂浇铸/粒子沥滤法制备聚ε-己内酯组织工程支架

对经典的溶剂浇铸／粒子沥滤法进行适当改进，结合致孔剂直接黏结工艺制备三维多孔聚ε-己内酯（PCL）组织工程支架材料.以氯化钠为致孔剂，利用预成型-真空浇铸-脱溶荆工艺制得支架材料．对支架的微结构、孔径、孔隙率和亲水性等性能进行表征．结果表明，黏结工艺中加入水量在2％～8％时都可形成均匀多孔黏结结构，且支架孔隙率几乎不变；支架孔径基本分布在10～80μm；孔隙率可达（89±1）％；采用抽真空与加热相结合的脱溶荆工艺可以提高孔隙率．制得的PCL支架厚度2〉5mm且为三维高孔隙率海绵体结构，可适用于软组织工程的修复．     

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.     

3D打印技术制备明胶纳米微球基复合凝胶支架

以明胶为原料,使用两步去溶剂法分别合成了具有相反电荷的两种纳米微球,将它们混合后分别溶于水、明胶溶液和丝素蛋白溶液形成3种凝胶.使用3D打印技术对3种凝胶进行加工,成功制备了3种三维多孔的支架.明胶增强的支架与丝素蛋白增强的支架在冷冻干燥以后分别使用1-乙基-(3-二甲基氨基丙基)碳二亚胺盐酸盐(EDC)/羟基丁二酰亚胺(NHS)和乙醇进行交联.通过扫描电镜(SEM)观察支架的形态并研究支架的膨胀性质.实验结果表明,仅靠纳米微球之间相互的作用力无法维持支架在水中的稳定结构,而使用明胶和丝素蛋白增强的支架则可以克服这种缺点.     

气体发泡PLA/PS共混高聚物制备组织工程支架研究

相互联通的三维可控孔隙结构是组织工程支架材料设计的关键.介绍了一种通过气体物理发泡工艺制备多孔生物支架材料的方法,研究了对不可共混的双相高分子材料聚乳酸与聚苯乙烯进行可控发泡的设计,发泡后经溶蚀工艺处理得到相互联通的孔隙结构.成骨细胞种植实验结果显示,细胞在支架中生长情况良好,经2周培养初步表现出在三维空间蔓延传递生长的特征,表明此方法为制备三维可控多孔类组织工程支架材料提供了一种有效设计途径.     

溶剂浇铸-粒子沥滤法制备PBS/PCL组织工程支架

选用聚丁二酸丁二醇酯(PBS)/聚ε-已内酯(PCL)共混材料作为组织工程支架材料基质,氯化钠和葡萄糖颗粒作为致孔剂,在传统的溶刺浇铸-粒子沥滤法的基础上,通过调节PBS/PCL的质量分数制得了不同尺寸且孔径、孔隙率满足组织工程支架要求的PBS/PCL多孔支架.对多孔支架的微结构、孔径、孔形态和素水性进行了表征,研究了PBS/PCL的质量分数、致孔剂粒径对支架成型及孔隙率的影响.结果表明,PBS/PCL的质量分教对支架成型影响较大,过低或过高的质量分数都会导致支架成型性差,质量分数在6%～10%时支架成型较好.利用质量分数为8%的PBS/PCL溶液可以制备形状复杂的多孔支架.所制支架内部孔洞分布均匀,贯通性好,孔径可由致孔剂的粒径来调控,支架孔隙率为86%～93%.支架亲水性良好,吸水率随孔隙率的增大而上升.     

聚乙烯醇及改性聚乙烯醇/明胶多孔支架的体外生物相容性研究

以吐温80为发泡剂,采用乳化发泡/冷冻—解冻法制备多孔的聚乙烯醇(PVA)和改性聚乙烯醇/明胶(PVA/Gel)支架材料,用扫描电子显微镜(SEM)对其形貌进行观察,并通过体外细胞培养对支架的生物相容性进行评价.实验结果表明,用该方法制备的多孔支架具有良好的贯通性,且PVA/Gel支架贯通性高于PVA支架;细胞结果显示,乳化发泡法制备的多孔支架对细胞的黏附、增殖和形貌无不良影响;荧光染色结果表明,PVA/Gel支架由于引入了大量氨基,使得细胞的黏附力优于PVA支架,具有更好的生物相容性.     

丝素包埋SPA成膜的理化性能和生物效应研究

研究将丝素溶液包埋金黄色葡萄球菌A蛋白(staphylococcal protein A)(简称A蛋白或SPA ),制成不溶性SPA丝素膜.用粘附生长因子RGD(序列为GLY-ARG-GLY-ASP-SER-PRO-L YS)的抗体IgG结合IgG到该丝素膜的表面,再将RGD结合到不溶性SPA丝素膜表面RGD抗体IgG 上,制备成RGD-IgG-SPA丝素膜.用酶联免疫吸附试验(简称ELISA)方法,证明RGD-IgG -SPA丝素膜是稳定的.种植培养血管内皮细胞(vascular endothelial cell,简称EC细胞) 于该改性丝素膜的表面,用四甲基偶氮唑盐比色方法(简称MTT法)检测细胞的生长,证明改性丝素膜能有效地促进EC细胞的生长.     

Preparation of 3-D porous fibroin scaffolds by freeze drying with treatment of methanol solutions

In this study, silk scaffolds with appropriate porous structures were prepared by adjusting solution concentrations and providing treatment with methanol solutions in the way of freeze drying. The effects of the preparation conditions on the microstructures and properties of the scaffolds were discussed. Fibroin solutions with different concentrations of 4, 6, 8, 10 wt% were used respectively to prepare the scaffolds. The effects of the addition of 20 vol% methanol before or after freeze drying to the 4 wt% fibroin solution were investigated. As demonstrated by Scanning Electron Microscope (SEM), the fib-roin scaffolds prepared without methanol had porous microstructures composed of thin sheets, and the sizes of the pores decreased with the increase of the fibroin solution concentrations, while the scaffolds prepared in the presence of methanol showed porous microstructures formed by fine-particle aggregates. The porosities and mechanical properties of the prepared fibroin scaffolds under different conditions were tested. The crystalline structures and conformations of the fibroin scaffolds were detected by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD).     

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。     

VE TPGS-Loaded Silk Fibroin/Hydroxybutyl Chitosan Nanofibrous Scaffolds for Skin Care Application

Vitamin E（ VE） is an ideal antioxidant and a stabilizing agent in biological membranes. In this study,silk fibroin（ SF） /hydroxybutyl chitosan（ HBC） nanofibrous scaffolds are loaded with VE tocopherol polyethylene glycol 1000 succinate（ VE TPGS） via electrospinning. SEM images show that the average nanofibrous diameter has no significant difference when the content of VE TPGS increases to 4. 0%（ SF / HBC）. However,the average nanofibrous diameter decreases largely to 200 nm when the VE TPGS content reaches 6. 0%. Furthermore,VE TPGS presents a sustained release behavior from the nanofibrous scaffolds. Cell viability studies of mouse skin fibroblasts（ L929） demonstrate that VE TPGS loaded SF / HBC nanofibrous scaffolds present good cellular compatibility.Moreover,the incorporation of VE TPGS could strengthen the ability of SF / HBC nanofibrous scaffolds on protecting the cells against oxidation stress using the Tertbutyl hydroperoxide（ t-BHP）-induced oxidative injury model. Therefore,VE TPGS-loaded SF /HBC nanofibrous scaffolds might be potential candidates for personal skin care,wound dressing and skin tissue engineering scaffolds.     

Fine Structure of Regenerated Silk Fibroin Solids

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Covalently immobilized gelatin gradients within three-dimensional porous scaffolds

A stable gelatin gradient providing continuous increment of signaling for cell adhesion and proliferation was fabricated within 3D poly（L-lactic acid） （PLLA） scaffolds. The porous PLLA scaffold fabricated by NaCI particle leaching was vertically fixed on a glass vial. 1,6-Hexanediamine/propanol solution was continuously injected into the vial by a micropump to aminolyze the PLLA scaffold. As a result of reaction time difference, the introduced -NH2 groups increased continuously along with the longitude of the PLLA scaffold in the z-direction. After covalent immobilization of gelatin by glutaraldehyde coupling, the gelatin gradient scaffold was thus obtained. In vitro chondrocyte culture showed that the cells had higher viability and more extending morphology in the gelatin gradient scaffold than that in the uniform gelatin control.     

丝素在生物医学领域中的应用

讨论了丝素（silk fibroin,SF)与生物医学领域应用相关的基本性质，以及在生物分析及药物缓释载体，人工器官及组织工程支撑体材料中的应用现状，结论认为：丝素具有固化结晶方式的多样化。易于保持高度生物亲和性以及形成特殊的多孔性网状结构。丝素还具有优良的成膜特性，并且通过与其它一些天然高分子材料的复合与化学改性，可以进一步改善其物理性能，从而适宜于构建新型药物载体与人工器官，同时，针对丝素蛋白在体的生物相容性，在体降解特性方面存在的问题，认为其在体变化机制不仅取决于与之接触体液的化学构成，也与温度，力学环境等生物物理因素有关，因此其在体变化机制是生物力学与生物流变学的因素与生物化学因素协同控制的。     

丝素改性聚氨酯膜的物理性质及其细胞相容性

用丝素蛋白或丝素肽表面改性的聚氨酯膜表现出良好的柔韧性，它能够克服丝素膜刚而脆的弱点；由水分散型聚氨酯制备的改性膜的透气性高于疏水性聚氨酯膜；细胞培养实验结果表明：经丝素蛋白或丝素肽改性后，聚氨酯膜的生物相容性明显提高且处理效果是稳定的。     

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.