等离子体磺酸化丝素蛋白膜聚四氟乙烯复合小口径人工血管的制备

背景:丝素蛋白膜用二氧化硫处理后,可表现出抗凝血活性,但丝素成膜后柔韧性及抗牵拉伸展等性能较差,如果将丝素蛋白涂覆于膨体聚四氟乙烯人造血管表面,并对涂覆后的丝素膜进行磺酸化处理,不但解决了上述不良因素,还能显著改善膨体聚四氟乙烯人造血管的血液相容性。目的:研究等离子体磺酸化丝素蛋白膜聚四氟乙烯复合小口径人工血管(复合血管)的制备过程,并探讨其制备过程的可行性。方法:采用低温等离子体技术处理普通聚四氟乙烯人工血管内表面,将制备并浓缩到一定浓度的丝素蛋白溶液均匀涂覆到人工血管内表面,再次使用低温等离子体技术对人工血管内表面的丝素膜进行磺酸化处理。以普通聚四氟乙烯人工血管为对照,进行接触角及磺酸化效果检测。结果与结论:氩气低温等离子体处理前后接触角分别为87.7°和65.1°,涂覆丝素蛋白后接触角为106.2°,二氧化硫低温等离子体处理后接触角为92.9°;X射线光电子能谱仪检测对照丝素膜表面仅有微量的硫元素(0.12%)存在,经过二氧化硫等离子体处理后丝素表面的硫元素含量上升到2.89%;X射线光电子能谱图中的S2p峰拟合曲线显示了复合血管表面的S原子主要是磺酸基团(-SO3H)。说明实验已制备出理论上具有抗凝血性能的血管。     

一种新的人工血管涂层及其实验研究

目的为克服目前使用的人工血管涂层材料性质普遍不稳定、不易提纯、交联用难且价格昂贵的缺陷,作者进行了人工血管丝素蛋白涂层的实验研究.材料和方法将丝素蛋白浸渍涂层涤纶人工血管内外壁并使用甲醛交联固定.通过血管壁渗水率、形态学以及力学性能等体外试验评价丝素蛋白涂层人工血管是否达到人工血管植入前标准.结果未涂层人工血管管壁渗水率通过丝素蛋白涂层降低了99%,达到植入时不漏血的目的.丝素蛋白涂层占重(117±22)mg/g显著低于较InterGardTM血管胶原涂层占重(302±23)mg/g(P＜0.05).结论丝素蛋白涂层人工血管可操控性好,渗水率低.同时在体外具备良好的生物降解性能.     

丝素蛋白在小口径人工血管中的应用

背景：国内外众多学者将丝素蛋白应用到小口径人工血管中,得到的人工血管拥有较好的抗血栓性及优秀的机械强度,动物实验也取得了满意的远期通畅率。目的：概述丝素蛋白的生物化学性质,目前在血管中常用的改性手段,以及国内外小口径人工血管中丝素蛋白的具体应用。方法：应用计算机检索中国知网、Medline数据库及ScienceDirect数据库1980年1月至2013年12月有关小口径人造血管血液相容性方面的文献,中文检索词为“人工血管,丝素蛋白”,英文检索词为“Vascular grafts,silk fibroin”。结果与结论：丝素蛋白拥有可控的机械性能,可通过醇化等处理获得不同的顺应性。同时,丝素蛋白拥有良好的生物相容性,分解产物已知、无毒,满足生物医药材料的安全需求。此外,丝素蛋白易于整合抗凝集团,效果明显可靠,且易于内皮细胞定植生长,而短期内能否形成稳定牢固的内皮层是保证血管假体拥有理想远期通畅率的关键,因此丝素蛋白是制备小口径人工血管的理想材料。但是由于制作工艺等问题,中国早期应用丝素蛋白制作的人工血管并未得到长远的发展。近年来,随着纳米材料、仿生技术、组织工程类血管、静电纺丝等技术的研究发展,以及众多学者为应对小口径血管中复杂血流动力学环境对多层血管的研究尝试,为丝素蛋白在人工血管中的应用开辟了新的空间领域。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：     

编织型丝素纤维人工韧带及其体外降解性能研究

该研究制备了一种丝素纤维人工韧带,分别在PBS和蛋白酶XIV溶液中进行体外降解试验。并对其表面形态、质量损失、降解液pH及力学性能等进行了观察和测试。结果表明,PBS溶液中降解70天后,丝素纤维人工韧带表面形貌和质量损失率没有发生明显变化,力学性能基本保持不变,溶液pH稳定呈中性。而酶降解70天的丝素纤维人工韧带表面发现多根纤维断裂,质量损失率高达18.4%,丝素纤维人工韧带材料直径下降达21.8%,最大断裂强力损失了近50%。降解后溶液的pH值呈弱酸性,且溶液中存在肉眼可见的絮状物。蛋白酶XIV对天然蛋白丝素纤维人工韧带材料具有明显的降解作用。该研究可为体外评价可降解人工韧带降解速率、建立体内外降解性能之间的关系提供参考。     

丝素纤维人工韧带材料的表面改性及细胞相容性

该文研究设计并制备了一种可降解的丝素纤维人工韧带材料,并对其进行了表面改性和细胞相容性研究。以丝素纤维为原材料编织仿生结构的人工韧带,对其材料表面进行低温氧等离子体处理,再通过EDC/NHS接枝I型胶原蛋白。同法接枝人纤维蛋白原和转化因子TGF-β1结合肽到材料表面。对材料的细胞相容性进行评价,结果表明,经过等离子体处理和生物活性分子接枝后,细胞相容性有了进一步提升。成纤维细胞在接枝了人纤维蛋白原的材料表面活性更高。     

聚乳酸-透明质酸复合膜的制备及其性能研究

以疏水性聚乳酸为原料,采用静电纺丝工艺制备得到纤维膜,通过等离子体表面处理技术将亲水性透明质酸与纤维膜结合,制备得到聚乳酸-透明质酸复合膜。采用扫描电镜、接触角测量仪和万能拉力机对复合膜的表面纤维形貌、接触角、力学性能等进行了表征。结果表明,聚乳酸纺丝的最佳电压为15～20 kv,随纺丝液浓度的增大,纤维膜的力学性能得以提高,等离子体处理时间为8 min时,得到的复合膜具有较好的亲水性。     

等离子体处理的丝素蛋白作为人内皮细胞培养基质的研究

目的：探讨人血管内皮细胞在等离子体处理后的丝素蛋白膜表面的生长情况。方法：等离子体由气体射频放电产生，工作气体为SO2和NH3：材料表面元素进行XPS分析；用MTT法测定人脐静脉内皮细胞系HU-VEC细胞生长；周间接免疫荧光法检测该细胞内Ⅷ凝血因子相关抗原的表达。结果：SO2和NH3等离子体处理后，丝素蛋白膜表面分别被磺酸化和氨基酸化，并均能促进HUVEC细胞生长，而且对细胞形态和产生Ⅷ凝血因子的功能没有明显的影响。结论：等离子体处理的丝素蛋白可以作为人内皮细胞的一种良好的培养基质。     

丝素蛋白/聚己内酯纳米纤维支架生物相容性评价

目的:改善再生丝素蛋白的降解性及力学性能,评价丝素蛋白/聚己内酯纳米纤维支架神经生物材料的生物相容性。方法:采用静电纺丝技术制备丝素蛋白/聚己内酯纳米纤维支架。体外培养雪旺细胞并与支架及其浸提液共培养,通过荧光染色,细胞毒性试验(MTT法)检测其细胞生物相容性。将纤维支架材料在体外置于蛋白酶ⅪV溶液评价其体外降解行为;通过皮下埋植实验观察纤维材料在体内的局部组织反应。结果:丝素蛋白/聚己内酯支架材料,呈现三维网状结构。雪旺细胞具有良好的生长形态;无细胞毒性。随着丝素蛋白比例的降低,能够显著增加混合支架的降解速度。皮下移植实验未引起明显免疫排斥反应,炎症反应轻。结论:丝素蛋白/聚己内酯支架具有良好的生物相容性和生物可降解性,有望用于神经组织工程支架材料修复神经缺损。     

胶原/丝素电纺纳米纤维膜体外培养肝细胞的研究

本实验采用静电纺丝技术制备胶原/丝素纳米纤维支架,对支架上培养的人肿瘤肝细胞HepG2进行形态学观察、细胞功能和代谢功能检测。胶原/丝素纳米纤维支架以六氟异丙醇(HFIP)为溶剂通过静电纺丝技术制备,5种支架材料胶原和丝素配比分别为10∶0、7∶3、5∶5、3∶7、0∶10。扫描电镜结果显示制备的纤维平均直径在550～1100 nm之间,随着丝素含量的增加纤维平均直径增加。细胞培养结果显示HepG2细胞在材料表面生长状态良好并与支架材料紧密结合。随培养时间延长,常规培养组细胞在第5 d后逐渐死亡,失去细胞功能,胶原/丝素纳米纤维支架组细胞在4～9 d内能够维持稳定状态,其尿素合成、蛋白分泌与常规培养组有明显差别,其中丝素含量为50%组的细胞状态和细胞功能高于其它组。实验表明胶原/丝素纳米纤维支架材料细胞相容性良好,较之常规培养细胞增殖效果明显,维持功能表达时间延长,有望用于改善人工肝生物反应器中的细胞活性,维持细胞功能表达。     

多孔丝素材料组织相容性的初步研究

背景：丝素蛋白支架材料被植入生物体内后会发生降解且无法完全与宿主组织分离,这类材料生物相容性的研究大多为体外实验,其体内的组织相容性和降解过程的研究结果仍不充分。 目的：初步观察多孔丝素材料的体内组织相容性。 方法：将多孔丝素支架埋藏于SD大鼠背部皮下,术后2,4,6,8周分别取材,对伤口局部及材料情况大体观察,然后材料切片苏木精-伊红染色行组织学观察。 结果与结论：动物伤口愈合良好,多孔丝素表面形成极薄的纤维包裹,周围组织反应轻微。组织切片见炎细胞浸润,以巨噬细胞为主,支架材料边缘孔隙内有成纤维细胞和毛细血管长入。8周时材料边缘部分可见支架结构崩解现象,而材料内部变化不大。结果显示组织细胞可以沿多孔丝素支架表面贴附生长,提示支架材料具有较好的组织相容性。     

Biocompatibility and bioactivity of plasma-treated biodegradable poly(butylene succinate)

Poly(butylene succinate) (PBSu), a novel biodegradable aliphatic polyester with excellent processability and mechanical properties, is a promising substance for bone and cartilage repair. However, it typically suffers from insufficient biocompatibility and bioactivity after implantation into the human body. In this work, H(2)O or NH(3) plasma immersion ion implantation (PIII) is conducted for the first time to modify the PBSu surface. Both the treated and control specimens are characterized by X-ray photoelectron spectroscopy, contact angle measurements and atomic force microscopy. The plasma treatments improve the hydrophilicity and roughness of PBSu significantly and the different PIII processes result in similar hydrophilicity and topography. C-OH and C-NH(2) functional groups emerge on the PBSu surface after H(2)O and NH(3) PIII, respectively. The biological results demonstrate that both osteoblast compatibility and apatite formability are enhanced after H(2)O and NH(3) PIII. Furthermore, our results suggest that H(2)O PIII is more effective in rendering PBSu suitable for bone-replacement implants compared to NH(3) PIII.     

2-Methacryloyloxyethyl N-butylcarbamate: a new co-monomer for synthesis of polyurethane hydrogels with improved mechanical properties for biomedical applications

Hydrogels with tunable hydrophilic and mechanical properties were synthesized by the free radical polymerization of 2-hydroxyethyl methacrylate (HEMA) and 2-methacryloyloxyethyl N-butylcarbamate. The resulting hydrogels were investigated for their equilibrium water content, sessile drop water contact angles, gel fraction, mechanical properties and protein adsorption. Results indicated that co-polymer hydrogels have good hydrophilicity and that, with the incorporation of the 2-methacryloyloxyethyl N-butylcarbamate, mechanical properties could be improved significantly without affecting other important properties. Lysozyme and albumin adsorption experiments demonstrated that, similar to most hydrogel materials, the co-polymer hydrogels adsorb more lysozyme than albumin and that the adsorption was dependent on hydrophilicity. The control poly(HEMA) hydrogels were found to adsorb more protein than the co-polymer hydrogels; this is thought to be primarily a consequence of protein absorption rather than protein adsorption.     

2-methacryloyloxyethyl N-butylcarbamate: a new co-monomer for synthesis of polyurethane hydrogels with improved mechanical properties for biomedical applications

Hydrogels with tunable hydrophilic and mechanical properties were synthesized by the free radical polymerization of 2-hydroxyethyl methacrylate (HEMA) and 2-methacryloyloxyethyl N-butylcarbamate. The resulting hydrogels were investigated for their equilibrium water content, sessile drop water contact angles, gel fraction, mechanical properties and protein adsorption. Results indicated that co-polymer hydrogels have good hydrophilicity and that, with the incorporation of the 2-methacryloyloxyethyl N-butylcarbamate, mechanical properties could be improved significantly. without affecting other important properties. Lysozyme and albumin adsorption experiments demonstrated that, similar to most hydrogel materials, the co-polymer hydrogels adsorb more lysozyme than albumin and that the adsorption was dependent on hydrophilicity. The control poly(HEMA) hydrogels were found to adsorb more protein than the co-polymer hydrogels; this is thought to be primarily a consequence of protein absorption rather than protein adsorption.     

Characterization of low-temperature-plasma treated silk fibroin fabrics by ESCA and the use of the fabrics as an enzyme-immobilization support.

Bombyx mori silk fibroin fabrics were treated with low-temperature-plasma using various gases. Alkaline phosphatase was immobilized onto the fabrics using the CNBr method. The enzyme activity was much improved by plasma treatment, especially when both O2 and CF4 were used. Using the ESCA technique it was found that the activities of the immobilized enzyme were strongly correlated with the C1s peak intensities of the atomic group -C-O-CF3. The apparent Michaelis constant for the enzyme decreased with increasing amounts of -C-O-CF3.     

Preparation and in vitro/in vivo evaluations of dimpled poly(l-lactic acid) fibers mixed/coated with hydroxyapatite nanocrystals

A novel hydroxyapatite (HAp)/poly(l-lactic acid) (PLLA) nanocomposite nonwoven fabric, which was coated and mixed with calcined HAp nanocrystals, and has submicron-sized dimples on its surface, was fabricated. First, HAp-mixed PLLA fabric was prepared by electrospinning a HAp nanocrystal dispersion in dichloromethane (DCM)-dissolved PLLA. It was found that most of the HAp nanocrystals were not exposed on the HAp-mixed PLLA fiber surface but covered with the PLLA matrix. A HAp-nanocrystal coating was applied onto the surface of the HAp-mixed PLLA fabric after corona discharge treatment followed by ethanol washing. The submicron-sized dimples were enlarged after the ethanol washing. After the HAp-nanocrystal coating, the HAp-mixed PLLA fabric surface was uniformly coated with the HAp nanocrystals. In vitro cell spread tests showed that the rat osteoblasts spread more on HAp-nanocrystal-coated fabrics than on non-HAp-coated fabrics. Upon covering calvarial defects, the in vivo hard tissue responses suggested earlier restoration of the defects with HAp-nanocrystal-coated fabrics than those with non-HAp-coated fabrics.     

Effect of the fiber diameter and porosity of non-woven PET fabrics on the osteogenic differentiation of mesenchymal stem cells

The proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) was investigated in three-dimensional non-woven fabrics prepared from polyethylene terephthalate (PET) fiber with different diameters. When seeded into the fabrics of cell scaffold, more MSC attached in the fabric of thicker PET fibers than that of thinner ones, irrespective of the fabric porosity. The morphology of cells attached became more spreaded with an increase in the fiber diameter of fabrics. The rate of MSC proliferation depended on the PET fiber diameter and porosity of fabrics: the bigger the fiber diameter of fabrics with higher porosity, the higher their proliferation rate. When the alkaline phosphatase (ALP) activity and osteocalcin content of MSC cultured in different types of fabrics was measured to evaluate the ostegenic differentiation, they became maximum for the non-woven fabrics with a fiber diameter of 9.0 microm, although the values of low-porous fabrics were significantly high compared with those of high porous fabrics. We concluded that the attachment, proliferation and bone differentiation of MSC was influenced by the fiber diameter and porosity of non-woven fabrics as the scaffold.     

Effect of the fiber diameter and porosity of non-woven PET fabrics on the osteogenic differentiation of mesenchymal stem cells

The proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) was investigated in three-dimensional non-woven fabrics prepared from polyethylene terephthalate (PET) fiber with different diameters. When seeded into the fabrics of cell scaffold, more MSC attached in the fabric of thicker PET fibers than that of thinner ones, irrespective of the fabric porosity. The morphology of cells attached became more spreaded with an increase in the fiber diameter of fabrics. The rate of MSC proliferation depended on the PET fiber diameter and porosity of fabrics: the bigger the fiber diameter of fabrics with higher porosity, the higher their proliferation rate. When the alkaline phosphatase (ALP) activity and osteocalcin content of MSC cultured in different types of fabrics was measured to evaluate the ostegenic differentiation, they became maximum for the non-woven fabrics with a fiber diameter of 9.0 μm, although the values of low-porous fabrics were significantly high compared with those of high porous fabrics. We concluded that the attachment, proliferation and bone differentiation of MSC was influenced by the fiber diameter and porosity of non-woven fabrics as the scaffold.     

用于人体上肢运动姿态监测的聚吡咯导电织物的机电性能评价

针对当前可穿戴电子产品对柔性可拉伸纤维基传感元件的需求,探讨导电弹力机织物用于监测人体上肢复杂运动姿态的可行性。为此,采用原位聚合法制备3种不同类型的聚吡咯导电织物（棉/氨斜纹、棉/氨平纹和涤/氨平纹织物）,采用扫描电镜（SEM）观察聚合之后聚吡咯在织物中的分布状态;分别以这3种导电织物为传感元件,制作姿态监测织物传感器,进行上肢运动状态的准静态测试。扫描电镜图显示,聚吡咯不仅吸附在织物表面,且被吸附在织物内部的每一根纤维表面,可反映所制备导电织物作为传感器敏感材料的稳定性。准静态运动的测试结果表明,导电织物拉伸变形时,电阻变化的方向性差异能用于表征人体上肢的不同运动姿态,且表征过程中3种织物的电阻变化无明显差异。随后的棉/氨平纹导电织物弯曲运动实时测试表明,聚吡咯导电织物能够实时呈现人体关节的运动幅度及运动次数。通过观测聚吡咯导电织物的拉伸电阻变化及其方向性差异,可准确反映上肢的弯曲、旋转及其复合运动。     

Electrospun nano- to microfiber fabrics made of biodegradable copolyesters: structural characteristics, mechanical properties and cell adhesion potential

Nano- to micro-structured biodegradable poly(L-lactide-co-epsilon-caprolactone) (PLCL) fabrics were prepared by electrospinning. Electrospun microfiber fabrics with different compositions of PLCL (mol% in feed; 70/30, 50/50, and 30/70), poly(L-lactide) (PLL) and poly(epsilon-caprolactone) (PCL) were obtained using methylene chloride (MC) as a solvent. The PLL microfiber exhibited a nanoscale-pore structure with a pore diameter of approximately 200-800 nm at the surface and subsurface regions, whereas such a surface structure was hardly observed in other polymers containing CL. The microfiber fabric made of PLCL 50/50 was elastomeric. Nanoscale-fiber fabrics with PLCL 50/50 (approx. 0.3 or 1.2 microm in diameter) were electrospun using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as a solvent. Mercury porosimetry showed that the decrease in the fiber diameter of the fabric decreased porosity, but increased fiber density and mechanical strength. Human umbilical vein endothelial cells (HUVECs) were adhered well and proliferated on the small-diameter-fiber fabrics (0.3 and 1.2 microm in diameter), both of which are dense fabrics, whereas markedly reduced cell adhesion, restricted cell spreading and no signs of proliferation were observed on the large-diameter-fiber fabric (7.0 microm in diameter). The potential biomedical application of electrospun PLCL 50/50 was discussed.     

Adsorption behavior of antimicrobial peptide histatin 5 on PMMA

Adsorption of antimicrobial peptide histatin 5 on a poly(methyl methacrylate) denture base may serve to prevent biofilm formation, leading to a reduction of denture-induced stomatitis. This study focused on adsorption behavior of histatin 5 onto PMMA surfaces modified using a cold plasma technique and the effectiveness of histatin 5 adsorption for reducing Candida albicans biofilm formation by the quartz crystal microbalance-dissipation (QCM-D) technique. PMMA spin-coated specimens were treated with oxygen (O(2)) plasma using a plasma surface modification apparatus. The amount of histatin 5 adsorbed onto the PMMA treated with O(2) plasma is more than six times greater than that adsorbed onto untreated PMMA. The degree of histatin 5 adsorption had a negative correlation with the contact angle, whereas that of zeta-potential showed no significant correlation. XPS analysis revealed that the introduction of the carboxyl and O(2) functional groups were observable on the O(2) plasma-treated PMMA. Increased surface hydrophilicity and the formation of the carboxyl could be responsible for histatin 5 adsorption on plasma-treated PMMA. There is no significant difference between histatin-adsorbed PMMA and control PMMA for C. albicans initially attached. On the contrary, the amount of C. albicans colonization on histatin-adsorbed PMMA was significantly less than the control.