共查询到20条相似文献,搜索用时 15 毫秒
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Silk fibroin (SF) from the Bombyx mori silkworm exhibits attractive potential applications as biomechanical materials, due to its unique mechanical and biological properties. This review outlines the structure and properties of SF, including of its biocompatibility and biodegradability. It highlights recent researches on the fabrication of various SF-based composites scaffolds that are promising for tissue engineering applications, and discusses synthetic methods of various SF-based composites scaffolds and valuable approaches for controlling cell behaviors to promote the tissue repair. The function of extracellular matrices and their interaction with cells are also reviewed here. 相似文献
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Ulla König Anja Lode Petra B. Welzel Yuichiro Ueda Sven Knaack Anja Henß Anke Hauswald Michael Gelinsky 《Journal of materials science. Materials in medicine》2014,25(3):607-621
This study intended to evaluate a contemporary concept of scaffolding in bone tissue engineering in order to mimic functions of the extracellular matrix. The investigated approach considered the effect of the glycosaminoglycan heparin on structural and biological properties of a synthetic biomimetic bone graft material consisting of mineralized collagen. Two strategies for heparin functionalization were explored in order to receive a three-component bone substitute material. Heparin was either incorporated during matrix synthesis by mixing with collagen prior to simultaneous fibril reassembly and mineralization (in situ) or added to the matrix after fabrication (a posteriori). Both methods resulted in an incorporation of comparable amounts of heparin, though its distribution in the matrix varied as indicated by TOF-SIMS analyses, and a similar modulation of their protein binding properties. Differential scanning calorimetry revealed that the thermal stability and thereby the degree of crosslinking of the heparinized matrices was increased. However, in contrast to the a posteriori modification, the in situ integration of heparin led to considerable changes of morphology and composition of the matrix: a more open network of collagen fibers yielding a more porous surface and a reduced mineral content were observed. Cell culture experiments with human mesenchymal stem cells (hMSC) revealed a strong influence of the mode of heparin functionalization on cellular processes, as demonstrated for proliferation and osteogenic differentiation of hMSC. Our results indicate that not only heparin per se but also the way of its incorporation into a collagenous matrix determines the cell response. In conclusion, the a posteriori modification was beneficial to support adhesion, proliferation and differentiation of hMSC. 相似文献
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We measured radiance distributions for black lining cloth and copper gauze using the convenient technique of wrapping the materials around a circular cylinder, irradiating it with a parallel light source and collecting the scattered radiance by a digital camera. One family of parallel threads (weave or weft) was parallel to the cylinder generator. The most salient features for such glossy plane weaves are a splitting up of the reflection peak due to the wavy variations in local slopes of the threads around the cylinders and a surface scattering lobe due to the threads that run along the cylinder. These scattering characteristics are quite different from the (off-)specular peaks and lobes that were found before for random rough specular surfaces. The split off-specular reflection is due to the regular structures in our samples of man-made materials. We derived simple approximations for these reflectance characteristics using geometrical optics. 相似文献
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为研究纳米改性对复合材料力学性能的影响,以纳米黏土改性环氧树脂与固化剂混合胶液为基体,以三维正交机织玻璃纤维织物为增强体,利用真空辅助树脂传递模压工艺(Vacuum assisted resin transfer molding,VARTM),制备纳米增韧三维正交玻璃纤维机织物增强环氧树脂复合材料。分别测试不同质量分数(1wt%、2wt%、3wt%、4wt%)纳米黏土改性复合材料沿0°和90°方向的弯曲和拉伸性能。结果表明:当纳米黏土质量分数为1wt%时,复合材料弯曲强度最大,沿0°和90°方向的弯曲强度分别增大了约7.21%和13.71%,弯曲模量分别增大了约5.69%和16.64%。当纳米黏土质量分数为3wt%时,复合材料拉伸强度最大,沿0°和90°方向的拉伸强度分别增大了约24.96%和27.93%,拉伸模量分别增加了约21.35%和13.26%。这是由于纳米黏土呈纳米尺度以片层状分散于环氧树脂中,增加了两相间的接触面积,提高纤维/树脂界面的结合力,进而增强了复合材料的力学性能。 相似文献
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Controlled functionalization of graphene oxide through surface modification with acetone 总被引:2,自引:0,他引:2
The facile method to functionalize graphene oxide through surface modification with acetone was studied and improved. The resulting nanomaterials showed variable characteristics as the surface energy could be tailored according to the combination (proportion of H2O to acetone) of mixed solvent under sonication. Stability test and contact angle measurement showed that the treated graphene oxide exhibited different dispersibility and wettability. SEM images of graphene oxide films corroborated the changes in chemical composition of the sheets. FT-IR, XPS, and TGA observation provided direct evidence for chemical composition changes occurred on the surface. The presence of alkyl chain could decrease the surface energy and obviously control the hydrophilicity of the graphene oxide sheets. These results will provide significant guidance for the study of graphene-based bio-materials and nano-composites. 相似文献
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《Materials Letters》2007,61(8-9):1641-1644
The cytotoxicity of CdSe quantum dots (QDs) with surface modification was reported first in the paper. CdSe QDs were incorporated into poly (d, l) lactide (PLA) nanoparticles and then surface modified with Fluronic® 68 (F-68), cetyltrimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), respectively. Three different particle sizes and zeta potential of the surface modified CdSe QDs were produced using a nano-precipitation method. The cytotoxicity of the surface modified CdSe QDs was evaluated in HepG2 cell model with MTT viability assay. The results showed that the cytotoxicity of the surface modified CdSe QDs in vitro was dependent on the surface properties. Surface modification with F-68 and SDS could lessen the cytotoxicity of CdSe QDs, while surface modification with CTAB showed significant cell damage. CdSe QDs surface modified with F-68 were injected into mice and the fluorescence images in viscus were obtained. The results suggested that CdSe QDs surface modified with F-68 have low cytotoxicity and good potential for biological labeling and imaging applications. 相似文献
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Tinneke Jacobs Heidi Declercq Nathalie De Geyter Ria Cornelissen Peter Dubruel Christophe Leys Arnaud Beaurain Edmond Payen Rino Morent 《Journal of materials science. Materials in medicine》2013,24(2):469-478
In this work, medium pressure plasma treatment of polylactic acid (PLA) is investigated. PLA is a biocompatible aliphatic polymer, which can be used for bone fixation devices and tissue engineering scaffolds. Due to inadequate surface properties, cell adhesion and proliferation are far less than optimal and a surface modification is required for most biomedical applications. By using a dielectric barrier discharge (DBD) operating at medium pressure in different atmospheres, the surface properties of a PLA foil are modified. After plasma treatment, water contact angle measurements showed an increased hydrophilic character of the foil surface. X-ray photoelectron spectroscopy (XPS) revealed an increased oxygen content. Cell culture tests showed that plasma modification of PLA films increased the initial cell attachment both quantitatively and qualitatively. After 1 day, cells on plasma-treated PLA showed a superior cell morphology in comparison with unmodified PLA samples. However, after 7 days of culture, no significant differences were observed between untreated and plasma-modified PLA samples. While plasma treatment improves the initial cell attachment, it does not seem to influence cell proliferation. It has also been observed that the difference between the 3 discharge gases is negligible when looking at the improved cell-material interactions. From economical point of view, plasma treatments in air are thus the best choice. 相似文献
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通过分析复合材料平面织物预成形体在铺覆过程中的变形模式,提出铺覆仿真计算的织物变形基本假设。分析已存在的几种渔网铺覆算法,提出一种基于曲面信息的改进渔网算法(SIB渔网法),该算法利用相邻节点处的曲面切向量及曲率信息来确定当前节点位置,避免了高强度的迭代计算,提高了仿真精度。研究采用非均匀有理B样条(NURBS)技术表达的复杂曲面求交算法。通过不同算法对球面、马鞍面仿真的结果对比,验证了SIB渔网法对复杂曲面铺覆计算的精确性及稳定性。 相似文献
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金属钴对储氢合金电极的表面修饰研究 总被引:2,自引:0,他引:2
运用真空蒸镀法时MH/Ni电池储氢合金电极进行了镀覆金属钴的表面修饰,测试了电池的放电容量、高倍率放电性能、循环寿命和充电时的内压,利用XPS和XRD时电极进行了表面和结构分析。实验结果表明,运用该方法对电极进行表面修饰可以降低电池内阻,提高电池的放电容量和放电电压,极片经过修饰的电池,5C(8.5A)放电容量提高了120mAh,放电平台电压提高了约0.05V,内阻降低了19.3%。极片经过表面镀钴后,显著改善了电池的循环性能,电池500周循环后的放电容量仍为初始容量的94.09/6,同时,电池在充电时的内压有了明显的降低,充电效率有了较大的提高。 相似文献
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Nanocrystalline NiO thin films were prepared by dc reactive magnetron sputtering in a mixture of oxygen and argon and subsequently coated by Pt on an NiO film surface. Very thin Pt overlayers with a thickness of about 3 and 5 nm have been deposited by magnetron sputtering. Then, the modified NiO films have been analyzed by TEM, EELS and AES. NiO thin films showed a polycrystalline structure (fcc NiO phase) with the size of nanocrystals ranging from a few nanometres to 10 nm. TEM observations both of unmodified and Pt-modified NiO films revealed that they were formed by nanocrystals and an amorphous phase. Uniformly distributed Pt particles were produced on top of the NiO surface. According to AES measurements, the presence of Ni in the spectra recorded from Pt pad indicated that the Pt layer has discontinuous nature. Electrical responses of NiO-based sensor structures towards hydrogen have been measured. 相似文献
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A marked improvement in the interlaminar shear strength and flexural strength of aramid/ epoxy composites is observed when
the fibres are pretreated in an ammonia or ammonia/ nitrogen gaseous discharge (plasma) to introduce amine groups on to the
fibre surface. Scanning electron and optical microscopic observations are used to examine the microscopic basis for these
results. Scanning electron micrographs of shear fracture surfaces show clean fibre/matrix separation in composites made from
untreated fibres, indicative of weak interfacial bonding. In contrast, shear fracture surfaces of composites containing plasma-treated
fibres exhibit clear evidence of fibre fibrillation and matrix cracking, suggesting stronger interfacial bonding. Optical
microscopic examination of flexure specimens shows that enhanced strength results mainly from reduced compressive fibre buckling
and debonding, due to an increase in fibre/matrix interfacial bond strength. This increase is not accompanied by any significant
change in the interlaminar fracture energy or flexural modulus of the composites, but there is an appreciable loss in transverse
ballistic impact properties. These results are also examined in terms of the observed increase in fibre/matrix interfacial
strength. 相似文献
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The interlaminar shear strength, interlaminar fracture energy, flexural strength and modulus of extended-chain polyethylene/epoxy composites are improved substantially when the fibres are pretreated in an ammonia plasma to introduce amine groups on to the fibre surface. These property changes are examined in terms of the microscopic properties of the fibre/matrix interface. Fracture surface micrographs show clean interfacial tensile and shear fracture in composites made from untreated fibres, indicative of a weak interfacial bond. In contrast, fracture surfaces of composites made from ammonia plasma-treated fibres exhibit fibre fibrillation and internal shear failure as well as matrix cracking, suggesting stronger fibre/matrix bonding, in accord with the observed increase in interlaminar fracture energy and shear strength. Failure of flexural test specimens occurs exclusively in compression, and the enhanced flexural strength and modulus of composites containing plasma-treated fibres result mainly from reduced compressive fibre buckling and debonding due to stronger interfacial bonding. Fibre treatment by ammonia plasma also causes an appreciable loss in the transverse ballistic impact properties of the composite, in accord with a higher fibre/matrix interfacial bond strength. 相似文献