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Heterogeneous structure of silk fibers from Bombyx mori resolved by 13C solid-state NMR spectroscopy
Asakura T Yao J Yamane T Umemura K Ulrich AS 《Journal of the American Chemical Society》2002,124(30):8794-8795
The molecular conformation of silk fibrion is characterized by solid-state 13C NMR before spinning (silk I structure) and after spinning (silk II structure). We compare native silk fibers with the quasi-crystalline Cp-fraction and a synthetic model peptide (Ala-Gly)15, both of which can be converted either into silk I by dialysis from 9 M LiBr or into silk II by treatment with formic acid. Our results demonstrate that silk II fibers are intrinsically heterogeneous, consisting of beta-sheets, distorted beta-turns, and distorted beta-sheets. This higher-order heterogeneity is revealed by the 13C-NMR Cbeta-peak of Ala, indicating that the Ala side chains are stacked partially in parallel and partially face-to-face, at a ratio of 1:2. 相似文献
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Li Zhen Gong Wenli Chen Xuan Liu Lin Meng Ranju Ding Yanhong Yao Juming 《Cellulose (London, England)》2021,28(17):11097-11108
Cellulose - Green bio-flocculants from renewable biomass resources have received the widespread attention for wastewater treatment, which are promising alternatives to petroleum-based synthetic... 相似文献
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A two‐step method was used to fabricate the hydroxyapatite (HAP)/silk fibroin (SF) scaffolds, i.e. the nano‐sized HAP/SF composite powders were prepared by co‐precipitation, which were then blended with SF solution to fabricate the HAP/SF composite scaffolds. The obtained scaffolds showed a 3D porous structure. The porosity was higher than 90% with the average macropore size of 214.2 µm. Moreover, the nano‐sized HAP/SF composite powders were uniformly dispersed in the silk fibroin matrix, which provided the scaffolds enhanced compressive properties. The cell culture assay showed that the scaffolds fabricated by the two‐step method could improve the cell proliferation and osteogenic differentiation when compared with those prepared by the conventional one‐step blending method. The results suggested that the two‐step method could promote the uniform dispersion of HAP in the SF matrix and efficient combination between the HAP and the matrix, which may provide a potential application in the composite scaffold preparation for tissue engineering. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Wei K Li Y Lei X Yang H Teramoto A Yao J Abe K Ko FK 《Macromolecular bioscience》2011,11(11):1526-1536
The effectiveness of a multifunctional scaffold produced by the electrospinning of emulsions composed of organic PLGA and aqueous collagen-like protein (denoted as Fol-8Col) solutions is demonstrated. The resultant Fol-8Col/PLGA fibrous scaffolds with homogeneous morphology have mean fiber diameters from 600 to 2,000 nm. A uniform distribution of encapsulated Fol-8Col in the fibers is observed by fluorescence microscopy. TEM is used to clarify the representative core/sheath structure of emulsion electrospun Fol-8Col/PLGA fibers. Preliminary release assessment of encapsulated Fol-8Col shows results of sustained release for more than one month from the Fol-8Col/PLGA fibrous mats. The cytocompatibility of fibroblast cell line L929 with the fibrous composite seems promosing. 相似文献
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Sosulski Krystyna Wang Sunmin Ingledew W. M. Sosulski Frank W. Tang Juming 《Applied biochemistry and biotechnology》1997,(1):59-70
Rye, triticale, and barley were evaluated as starch feedstock to replace wheat for ethanol production. Preprocessing of grain
by abrasion on a Satake mill reduced fiber and increased starch concentrations in feedstock for fermentations. Higher concentrations
of starch in flours from preprocessed cereal grains would increase plant throughput by 8–23% since more starch is processed
in the same weight of feedstock. Increased concentrations of starch for fermentation resulted in higher concentrations of
ethanol in beer. Energy requirements to produce one L of ethanol from preprocessed grains were reduced, the natural gas by
3.5–11.4%, whereas power consumption was reduced by 5.2–15.6%. 相似文献
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将丝素蛋白(SF)光诱导自交联原理与挤出式三维(3D)打印相结合, 开发了光交联自支撑SF水凝胶的原位成型加工技术. 采用旋转流变仪、 光流变测试系统和改装的挤出式3D打印设备等对SF溶液的流变性能、 光交联性能和成型加工性能等进行研究. 结果表明, SF溶液主要表现为黏性特征, 结构强度和稳定性均较差. 利用SF的光诱导自交联特性, 以三联吡啶氯化钌[Ru(Ⅱ)]和过硫酸钾(KPS)为蓝光引发体系, 可实现SF水凝胶的快速光交联成型. SF光交联行为符合指数函数增长模型, 因“滤镜效应”, 当Ru(Ⅱ)的浓度为0.05 mmol/L时, SF具有最佳的光交联性能. 通过调节气压、 针头孔径、 移动速度及固化速率等参数, 采用3D打印设备可实现从单层几何结构到多层三维网络构型SF凝胶材料的高效、 精准构建, 为SF的生物3D打印提供了新思路. 相似文献
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Direct Synthesis of Porous Nanorod‐Type Graphitic Carbon Nitride/CuO Composite from Cu–Melamine Supramolecular Framework towards Enhanced Photocatalytic Performance 下载免费PDF全文
Jiangpeng Wang Dr. Hui Xu Xuefeng Qian Yingying Dong Prof. Dr. Junkuo Gao Prof. Dr. Guodong Qian Prof. Dr. Juming Yao 《化学:亚洲杂志》2015,10(6):1276-1280
Facile and direct synthesis of porous nanorod‐type graphitic carbon nitride/CuO composite ( CuO‐g‐C3N4 ) has been achieved by using a Cu–melamine supramolecular framework as a precursor. The CuO‐g‐C3N4 nanocomposite demonstrated improved visible‐light‐driven photocatalytic activities. The results indicate that metal–melamine supramolecular frameworks can be promising precursors for the preparation of efficient g ‐C3N4 nanocomposite photocatalysts. 相似文献
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利用基于天然生物高分子的绿色环保法制备纳米贵金属材料是当今纳米技术发展的一个重要方向之一. 利用丝胶蛋白(SS)为还原剂和分散剂合成了纳米银颗粒, 利用紫外-可见(UV-Vis)光谱、X射线衍射(XRD)、透射电镜(TEM)等研究了反应温度、pH值、SS/Ag+物质的量比对反应速率和合成的纳米银粒子形貌的影响. 实验结果表明, 利用本方法可以合成尺寸均匀且分散性良好的球形纳米银粒子, 且随着反应温度和溶液pH值的逐渐升高, 反应速率随之加快, 合成的纳米银粒子的粒径逐渐变小, 而SS/Ag+物质的量比的变化主要对纳米银粒子的尺寸有影响. 相似文献