Structure Changes of Silk Fibroin(SF) by Blending with Poly(ε-caprolactone)(PCL):Characterization of SF and PCL Blended Electrospinning Films

The mechanical properties and water solubility of electrospinning SF films limit their use as biomaterials. In order to develop a tissue engineering biomaterial with both satisfying biological properties and sufficient biomechanical properties,blended films composed of silk fibroin( SF) and poly( ε-caprolactone)( PCL) were fabricated by electrospinning in this study. Scanning electron microscope( SEM), X-ray diffraction( XRD),thermal analysis,Fourier transform-infrared( FT-IR),Raman spectra,mechanical testing,and water solubility were used to characterize the morphological, structural and mechanical properties of the blended electrospinning films. Results showed that the diameter of the blended fiber was distributed between 600 and1000 nm,and the fiber diameter increased as the PCL content increased. There is no obvious phase separation due to the similarity and intermiscibility,as well as the interactions( mainly hydrogen bonds), between the two polymers. Meanwhile, the secondary structures of SF changed from random coils and Silk I to Silk II because of the interactions between SF and PCL. For this reason,the tensile strength and elongation at break of the electrospinning films improved significantly,and the water solubility decreased. In conclusion,the blended electrospinning films fabricated in this study showed satisfying mechanical properties and water insolubilities,and they may be promising biomaterials for applications in tissue engineering for blood vessels,nerve conduits,tendons,ligaments and other tissues.

Preparation of Nano Silver/Silk Fibroin Composite Films

In this study, the outstanding biocompatibility of silk fibroin （SF） and the highly efficient anti-bacterial effect of nano silver （NS） were utilized to prepare SF/NS composite film with anti- bacterial property. The structure and property of the film were characterized. The results showed that the structure of SF in the film was mainly silk I. SF in the film was almost insoluble in water. The tensile strength of film with NS was significantly lower than that of films without NS. When the addition of NS was within the range of 0%-0.6%, the elongation at break had no significant difference. The antibacterial rate of the film on staphylococcus aurens and escherichia coil increased with the amount of NS. The minimum amount of NS in the fdm was O. 1% and the maximum amount was 0.5%.

Fabrication of Ethosome-Loaded Silk Fibroin/Polyethylene Oxide Nanofibrous Mats by Green Electrospinning

Ethosomes are permeation-enhancing carriers, which significantly promote drug delivery into skin. Thus,the introduction of ethosomes into electrospun nanofibers may result in good effect on transdermal drug delivery. In this work,a novel ethosome-loaded silk fibroin( SF) /polyethylene oxide( PEO) composite nanofiber was fabricated based on a green electrospinning process. The ethosome-loaded SF /PEO nanofiber was round and smooth as shown by scanning electron microscopy( SEM),and the incorporation of ethosome didn't significantly affect the morphology of the electrospun SF /PEO nanofiber. The data of Fourier transform infrares(FTIR)spectra suggested the existence of ethosome on the SF /PEO nanofiber and the transmission electron microscopy(TEM) clearly showed the distribution of ethosome on the ethosome-loaded SF nanofibers. This ethosome-loaded SF nanofibrous mat may have a promising application in transdermal drug delivery systems.

Silk Fibroin/Poly-L-lactide Lactone Bi-layered Membranes for Guided Bone Regeneration

After removal of the caries or diseased teeth,the alveolar ridge will undergo absorption and atrophy.When the amount of alveolar bone is insufficient,it will cause an inability to perform effective dental implant restoration.In order to control the absorption and promote the repair and regeneration of alveolar ridge,a method of implanting guided bone regeneration(GBR)membranes at the extraction site is often used.In this study,silk fibroin(SF)and poly-L-lactide lactone(PLCL)were used to prepare bilayered guided bone regeneration membranes,and its morphology,hydrophilicity,surface roughness and mechanical properties were studied.At the same time,the drug release behaviors and cell compatibility of the bilayered membranes were studied.The results showed that SF/PLCL bi-layered membranes had good mechanical properties and surface hydrophilicity,and the drug-loaded bi-layered membranes had good cell compatibility.The bilayered membranes fabricated in this study are of potential for applying in the oral health field to promote bone regeneration.

Green Electrospun Silk Fibroin/Galactose Chitosan Composite Nanofibrous Scaffolds for Hepatic Tissue Engineering

The electrospun nanofibrous scaffolds made of proteins and polysaccharides were thought to be able to simulate the structure of natural extracellular matrix well.Silk fibroin(SF)and chitosan(CS)are probably the most widely used natural materials in biomedical fields including liver tissue engineering for their good properties and wide variety of sources.The asialoglycoprotein receptors of hepatocyte were reported to specifically recognize and interact with galactose.In this work,a green electrospun SF/galactosylated chitosan(GC)composite nanofibrous scaffold was fabricated and characterized.The data indicated that the addition of GC greatly influenced the spinning effect of SF aqueous solution,and the average diameter of the composite nanofibers was about 520nm.Moreover,the green electrospun SF/GC nanofibrous scaffolds were demonstrated significantly enhancing the adhesion and proliferation of hepatocyte(RH35)according to our data.The present study did a useful exploration on constructing scaffolds for liver regeneration by green electrospinning,and also laid a good foundation for the further applicative research of this green electrospun scaffolds in liver tissue engineering.

Fabrication and Drug Release Property of Silk Fibroin-Based Weft-Knitted Stents

This paper was to develop a weft-knitted stent coated by a drng-loaded electro-spun fibrous membrane and then investigate its morphology, mechan/cal properties and in vitro drug release property. This work was started by weft-knitting of an inner layer of such stent using polydioxanone （PDO） and silkf＇dment. Subsequently, 5-fluorouracil （5-FU） and curcnmin（CUR） loaded silk fibroin （SF） membranes were coated on the surface of the weft- knitted stent using electro-spinning technique to endow the drug delivery funct/on of the stent. The results show that the radial compression strength and c/renmferentlal expanding strength can reach above （9.1±0.4） cN/cm2 and （205.0± 0.2） cN/mm, respectively. The drug releasing behaviors can be sustained for 400 h. It is concluded that the stents have potential application as anintestinal stent in the future.

Silk Fibroin Film Blended with Poly( ethylene glycol-glycerin)

To improve the toughness of silk fibroin( SF) films,poly( ethylene glycol-glycerin)( PEGG) was synthesized with ethylene glycol and epichlorohydrin. The SF / PEGG blend films were prepared by casting aqueous solution and their structures were characterized. The PEGG was in liquid state at room temperature so it will not be a single phrase at blend film. It crosslinked with SF and made it insolubility in water. The results of X-ray diffraction( XRD) indicated that the crystallinity of the SF in the blend films decreased with the content of PEGG increasing. The tensile strength and elongation at break of blend films were measured using an instron tensile tester. The results showed that the tensile strength and elongation at break of blend films were high enough for application.After the blend films were stored at room temperature for 100 d,the crystallinity, the tensile strength and elongation at wet state increased. The blend films are superior to SF films in providing excellent flexibility and mechanical properties in both dry and wet states. Based on the fact that SF has good biocompatibility,the SF /PEGG blend film will offer new options in many different biomedical applications.

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.

Preparation of Antibacterial Electrospun PVA / Regenerated Silk Fibroin Nanofibrous Composite Containing Ciprofloxacin Hydrochloride as a Wound Dressing

Electrospinning technique was used for the fabrication of poly( vinyl alcohol)( PVA) / regenerated silk fibroin( SF)composite nanofibers,loaded with ciprofloxacin HCl( CipH Cl) as a wound dressing.Electrospun PVA / SF / CipH Cl composite nanofibers were stabilized against dissolving in water by heating in an oven at155 ℃ for 5 min.Incorporation of CipH Cl into electrospun nanofibers was confirmed by SEM and FT-IR spectra.Further the mechanical properties test illustrated that the addition of CipH Cl enhanced the mechanical properties of PVA and PVA / SF nanofibers.The antibacterial activities against Escherichia coli( E.coli)( gram-negative) and Staphylococcus aureus( S.aureus)( gram-positive) organisms were evaluated by disk diffusion method;and results suggested that electrospun PVA / CipH Cl and PVA / SF /CipH Cl composite nanofibers showed a remarkable antibacterial activity.

不同肝细胞配体修饰的壳聚糖作为肝组织再生支架材料的比较研究:制备、表征和评价

为了获得理想的肝脏再生支架,使用乳酸(lactobionic acid,LA)或/和甘草次酸(glycyrrhetinic acid,GA)对壳聚糖(chitosan,CS)进行改性,得到LA改性的CS(LC)、GA改性的CS(GC)和GA/LA双改性的CS(GLC),并采用绿色静电纺丝法制备了由丝素蛋白(silk fibroin,SF)和上述改性CS组成的复合纳米纤维支架。这些支架是亲水的,其亲水性和热稳定性随着改性CS的增加而降低,而结晶度则相反。这些支架在促进HepG2细胞增殖及分泌白蛋白和尿素方面表现出良好的性能。此外,与SF/GC或SF/GLC支架相比,SF/LC支架具有更好的肝细胞相容性。

丝素蛋白/羟基磷灰石复合材料的制备及性能表征

为了改善羟基磷灰石(HAP)的脆性和新骨诱导性,采用共沉淀法合成HAP,盐溶法制备丝素蛋白(SF),在胶体状态下将HAP和SF复合得到了SF/HAP复合材料。采用扫描电镜(SEM)、X射线衍射(XRD),傅立叶红外光谱(FIR)对复合材料结构和化学组成进行了分析,在模拟体液中检验了复合材料的生物活性,并对其抗压强度进行了测定。结果表明:HAP与SF在纳米尺度进行了复合,复合材料中SF主要以β-折叠构象存在,酰胺Ⅴ红外特征峰消失,β-折叠构象的其他峰发生了移动,表明HAP与SF间存在化学结合;模拟体液中浸泡18天后,复合材料表面形成了片层状的HAP;与纯的HAP晶体比较,复合材料结构稳定,具有较好生物活性和骨诱导性,其抗压强度可达63 MPa,可望成为理想的骨组织替换和工程支架材料。

丝素蛋白/左旋聚乳酸支架材料与软骨细胞体外细胞相容性研究

目的:观察静电纺丝支架材料丝素蛋白/左旋聚乳酸(SF/PLLA)的体外细胞相容性,探索其作为软骨组织工程支架材料的可行性,为进一步的体内及动物实验奠定基础。方法:将兔膝关节软骨细胞与丝素蛋白/左旋聚乳酸(SF/PLLA)支架材料复合培养,在第3、7、14天分别作HE染色和阿利新蓝+核固红染色,扫描电镜检验细胞黏着情况,MTT试验检测细胞在支架上的增殖情况。结果:细胞在支架上可以获得良好的粘附,细胞增殖良好,无细胞表型的变化。结论:丝素蛋白/左旋聚乳酸(SF/PLLA)具有良好的细胞相容性,可作为软骨组织工程支架材料。

静电纺丝天然-人工合成聚合物复合纳米纤维及其对细胞黏附、增殖和迁移的影响

生物材料组成成分对细胞生物功能有不同的影响。利用静电纺丝技术制备了基于聚己内酯(PCL,polycaprolactone)的不同天然蛋白、多糖(丝素蛋白(SF,silk fibroin)、透明质酸(HA,hyaluronicacid))的混合组分纳米纤维,采用了扫描电镜和接触角对纳米纤维进行基础表征。同时,进一步考察了纳米纤维作为组织工程支架的可行性。研究结果表明SF组分能增加材料的可纺性,有利于细胞的前期黏附,并能够促进细胞增殖。HA组分可以改善材料的亲水性,增加细胞伪足并促进细胞迁移。重要的是,PCL/SF/HA纳米纤维能同时结合SF和HA的优点,有望在组织工程领域得到应用。

丝素共混膜的研究进展

介绍丝素与聚乙烯醇、聚丙烯酰胺、壳聚糖、海藻酸钠和纤维素等聚合物的共混膜,比较分析丝素共混膜的结构、力学性能;综述了丝素共混膜作为细胞培养底物、可控药物释放载体、人工皮肤、人工肌腱、酶固定材料等在生物医学领域的应用研究进展;阐述丝素与聚合物共混制膜在生物医学和药学材料上应用的潜在价值。

再生丝素与无机纳米粒子复合膜的结构与性能

用溶胶-凝胶法制备了纳米二氧化钛再生丝素复合膜,并用扫描电镜(SEM)、X射线(XRD)、热重分析(TGA、DTG)对复合丝素膜的结构与性能进行了表征。结果表明:加入纳米二氧化钛颗粒后再生丝素膜的热转变温度提高;再生丝素的结晶构象由S ilk I向S ilk II转变,结晶度增加。

胶原/丝素膜的制备及其SO_2等离子体改性研究

利用丝素和胶原蛋白各自的优点,制备了胶原-丝素共混膜,并通过FTIR、TGA、SEM等手段对其结构进行了表征。选用SO2采用低温等离子体技术对胶原/丝素膜进行了表面处理。材料的体外抗凝血性能由体外凝血时间——凝血酶原时间(PT)、部分凝血活酶时间(APTT)、凝血酶时间(TT)作为评价标准。结果表明,共混膜中二组分间存在的分子间作用力,加入小于50%的丝素的胶原膜经乙醇处理后与纯胶原膜相比,其力学性能及热稳定性有所改善。通过改变丝素比例可以调整共混膜的吸水性。经SO2处理后由于在共混膜表面引入了磺酸基团,因而具有良好的抗凝血性能。

丝素蛋白及其复合材料的研究进展

丝素蛋白是天然高分子材料,具有很好的生物相容性、生物降解性等优良的性能,在医药、食品和美容等领域具有很好的发展前景。本文阐述了丝素蛋白及其分别与天然生物蛋白、无机物、合成聚合物、碳纳米管和氧化石墨烯进行复合的制备技术、材料结构、性能以及研究发展趋势,介绍了丝素蛋白及其复合材料的不同制备机制,分析了制备方法与结构和材料性能之间的关系及不同材料间的相互作用机理,总结了其在组织工程、药物释放和抗凝血性等方面的应用,并提出丝素蛋白复合材料实现规模化生产、发展智能材料以及从基因层面对丝素蛋白进行重组改性方面的未来发展趋势。

丝素蛋白膜修复海绵体神经缺损的实验研究

目的 探讨丝素蛋白膜（SF）修复海绵体神经缺损的效果.方法 选取健康雄性纯系SD大鼠33只,随机将其分成3组,假手术组（A组,n=11）、实验组（B组,n=11）及海绵体神经切断组（C组,n=11）.A组大鼠单纯游离双侧海绵体神经;B组大鼠首先建立海绵体缺损模型,后用SF桥接修复;C组大鼠切断双侧海绵体神经.术后3个月对各组大鼠进行阿朴吗啡试验,观察阴茎勃起情况并记录勃起次数.然后取阴茎中后部海绵体组织应用免疫组化方法检测神经型一氧化氮合酶（nNOS）的表达.对于所得数据使用SPSS17.0统计软件进行统计学分析.结果 A组与B组大鼠阴茎勃起次数、勃起率及nN0S神经纤维数目明显高于C组,统计学分析证实前两组与C组的差另别有统计学意义,前两组间的差别亦有统计学意义.结论 SF具有促进大鼠海绵体神经损伤修复的能力;本研究为丝素蛋白膜修复海绵体神经缺损的临床应用提供了实验依据.

丝素蛋白材料对成神经分化人脐带间充质干细胞生长的影响

目的 研究成神经分化的人脐带间充质干细胞(hUC-MSC)在丝素蛋白(SF)材料上的生长发育,明确细胞与SF膜材料的生物相容性。方法 从新生儿脐带分离培养hUC-MSC,接种在家蚕SF膜材料上,并诱导其向神经样细胞分化,作为实验组。同时在常规培养基上培养hUC-MSC作为对照组。对不同时间段的细胞进行β-Ⅲ-tubulin特异性免疫荧光染色,并通过CCK-8及流式细胞术等对细胞增殖及存活率等生物学性状进行分析。结果 经过诱导,hUC-MSC逐渐向成神经元样细胞分化,神经细胞特异性标志物Nestin和NSE呈阳性表达。SF薄膜能较好地支持成神经样分化hUC-MSC的生长。CCK-8及流式细胞检测表明SF膜能促进细胞的增殖并提高成活率。结论 SF膜具有良好的生物相容性,能有效支持成神经分化hUC-MSC的生长。

丝素/纳米纤维素晶须/壳聚糖多孔复合支架的应用

以冷冻干燥法制备多孔丝素(SF)支架,利用层层自组装将纳米纤维素晶须(CNW)和壳聚糖(CS)交替组装到多孔SF支架上得到SF/CNW-CS多孔复合支架。对SF/CNW-CS多孔复合支架的形貌和机械性能进行了表征。以MG-63细胞进行体外培养评估SF及SF/CNW-CS多孔复合支架的细胞相容性,MTT比色法和荧光图像的测试结果表明,与SF多孔支架相比,MG-63细胞在SF/CNW-CS多孔复合支架上的增殖、粘附和分化功能最高。因此,SF/CNW-CS支架有望成为骨组织工程的理想材料。