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1.
蒋伏广  姚晋荣  陈新  邵正中 《化学学报》2009,67(14):1675-1679
详细研究了不同浓度的聚丙烯酸(分子量为2000, PAA-2k)和镁离子对碳酸钙在再生丝素蛋白(RSF)膜表面结晶的影响. 发现单独采用PAA-2k时, 碳酸钙主要以方解石形式在RSF膜表面沉积成膜; 若加入一定量的镁离子参与共同调控, 碳酸钙则有可能在RSF膜表面形成以文石为主的连续薄膜, 进而得到了具有类珍珠质结构的层状RSF/文石复合材料. 我们认为, 吸附在RSF膜表面的PAA对碳酸钙成核诱导作用及其溶液中PAA对碳酸钙结晶抑制作用共同导致RSF膜表面碳酸钙薄膜的形成.  相似文献   

2.
陶瑜  顾恺  邵正中 《高分子学报》2021,(2):158-165,I0003
利用丝蛋白能够在还原氧化石墨烯片层上发生选择性聚集的特性,制备了还原氧化石墨烯片层上富集有丝蛋白微纤且分散性良好的还原氧化石墨烯片和丝蛋白混合溶液,并通过冷冻以及低温乙醇处理的方法得到一系列不同比例的还原氧化石墨烯/丝蛋白基多孔复合材料.随后,采用溶液浸泡的方法在多孔材料表面再次沉积还原氧化石墨烯,以进一步提高还原氧化石墨烯/丝蛋白基多孔复合材料的压敏导电性.系统观察和测试结果表明,还原氧化石墨烯的引入,不仅使得多孔材料内部出现了相应的微纳结构,同时也提高了多孔材料的力学性能.还原氧化石墨烯/丝蛋白基多孔复合材料在完全湿态下兼具较好的强度和弹性,可以在0%~80%的压缩应变之间实现良好的压缩回复效果和压力传感性能.其中,最佳比例下的还原氧化石墨烯/丝蛋白基多孔复合材料在低压力下的灵敏度可达0.15 kPa?1,在0~17.3 kPa范围内能够高效工作并且具有优异的电学稳定性和耐疲劳性.因此,还原氧化石墨烯/丝蛋白基多孔复合材料因其高灵敏度、宽工作范围、结构可调以及可塑性好等诸多优点,有望在柔性压力传感方面获得较好的应用.  相似文献   

3.
陈新 《高分子科学》2014,32(1):29-34
Ca(II) ions are added in the spinning dope to adjust the solidification rate of regenerated silk fibroin (RSF) solution during the wet-spinning process since Ca(II) ions are proved to be favorable to maintain the stable silk fibroin network in our previous work. The results show that when Ca(II)/RSF ratios are 1/50 and 1/20, the resulted RSF fibers exhibit good performance with the breaking energy more than 70 kJ/kg. However, higher Ca(II)/RSF ratio (for example, 1/10) hinders the solidification of spinning dope and results in poor RSF fibers. These observations together with earlier papers from this laboratory confirm that to produce tough silk fibers the spinning conditions must allow sufficient time for the adjustment of silk fibroin molecular chains.  相似文献   

4.
杨宇红  邵正中  陈新 《化学学报》2006,64(16):1730-1736
通过一系列光谱实验手段研究了再生桑蚕(Bombyx mori)丝素蛋白在水溶液中的构象转变情况. 由于丝素蛋白含有较多带电荷的氨基酸残基, 因此环境pH值对丝素蛋白的结构有着一定的影响: 酸性越强, 丝素蛋白越容易发生从无规线团到β-折叠结构转变; 相对而言, 碱性条件则更有利于丝素蛋白以无规线团结构稳定存在. 特别是当pH在4附近时, 丝素蛋白的无规结构最易发生改变; 而pH为6左右时, 丝素蛋白的结构则较为稳定. 这种变化趋势与沿着成熟蚕腺体中丝素蛋白所处的环境及其状态相当吻合, 由此表明pH值的调节是蚕在生物体中控制其丝素蛋白状态的一个相当重要的手段. 这一结果对人工纺制动物丝条件的调控有着极其重要的现实意义. 同时我们还发现, 在相当宽的pH范围内, 丝素蛋白的二级结构存在着中间体形态, 表明丝素蛋白的变性过程不符合简单的二态机制.  相似文献   

5.
The molecular weight (MW) of regenerated silk fibroin (RSF) decreases during degumming and dissolving processes. Although MW and the MW distribution generally affect polymer material processability and properties, few reports have described studies examining the influences of MW and the distribution on silk fibroin (SF) material. To prepare different MW SF fractions, the appropriate conditions for fractionation of RSF by ammonium sulfate (AS) precipitation process were investigated. The MW and the distribution of each fraction were found using gel permeation chromatography (GPC) and SDS-polyacrylamide electrophoresis (SDS-PAGE). After films of the fractionated SFs formed, the secondary structure, surface properties, and cell proliferation of films were evaluated. Nanofiber nonwoven mats and 3D porous sponges were fabricated using the fractionated SF aqueous solution. Then, their structures and mechanical properties were analyzed. The results showed AS precipitation using a dialysis membrane at low temperature to be a suitable fractionation method for RSF. Moreover, MW affects the nanofiber and sponge morphology and mechanical properties, although no influence of MW was observed on the secondary structure or crystallinity of the fabricated materials.  相似文献   

6.
江霞蓉  管娟  陈新  邵正中 《化学学报》2010,68(18):1909-1914
利用冰晶为模板并结合冷冻干燥技术, 成功地获得了具有一定力学强度的定向多孔丝蛋白支架. 采用扫描电镜、流变、拉曼光谱和压缩测试等方法, 考察了丝蛋白原液在不同pH值和初始浓度的情况下对定向支架的成因、内部形貌及力学性能的影响. 结果表明, 当溶液的pH值为4.4, 浓度由低到高时, 所制备的丝蛋白支架内部将分别出现纤维状结构、轴向片层状和梭状多孔结构. 特别是由初始浓度为15% (及以上)的丝蛋白溶液定向冷冻得到的支架, 在压缩试验中表现出较好的力学性能, 其轴向压缩模量和屈服应力分别达122.6和6.9 MPa, 满足了进一步应用的基本需求.  相似文献   

7.
Regenerated silk fibroin (RSF)/graphene oxide (GO) nanocomposite has been substantially investigated due to its significant multifunctional potential. Here, in combination of micromorphology, crystalline conformation, dynamic mechanical property characterization, and Fourier self‐deconvolution (FSD) quantitative analysis, we investigated the RSF molecular chains conformation transition induced by GO nanosheet incorporation, and its influence on the structural and mechanical properties of solution casted RSF/GO composite films. The GO nanosheet promoted the silk fibroin molecular chains conformation transition from random coil to β‐sheet structure, and a correlation between β‐sheet structure fraction and GO concentration was revealed. The β‐sheet structure fraction increases further improved the dynamic mechanical property of composite films. Moreover, based on nucleation‐dependent aggregation of silk fibroin molecular chains, a mechanism considering the competition effect between GO concentration and its total surface area was proposed to explain the observed concentration‐dependent conformation transition phenomenon. The study improves our understanding on silk fibroin conformation transition process in RSF/GO composite and would provide a valuable reference for the rational design of bioinspired multifunctional materials with enhanced mechanical properties. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1506–1515  相似文献   

8.
The structure and properties of the blend of regenerated silk fibroin (RSF) and poly(vinyl alcohol) (PVA) were investigated. The two polymers in the blend are in the state of phase segregation. Infrared (IR) spectra indicate that the RSF in the blend maintains its intrinsic properties, thus, ethanol treatment can transfer silk I structure of RSF to silk II structure. The water absorption property and mechanical property of the blend are improved in comparison with those of RSF. The blend maintains the major merit of RSF, that is, it can immobilize glucose oxidase on the basis of the conformational transition from silk I structure to silk II structure. The properties of the immobilized enzyme are examined. Moreover, the second generation of glucose sensor based on the immobilized enzyme is fabricated and it has a variety of advantages including easy maintenance of enzyme, simplicity of construction, fast response time and high stability.  相似文献   

9.
Starch and polyvinyl alcohol composite films, reinforced with raw and methylmethacrylate-grafted silk fibroin particles, were prepared by the solution-casting method on leveled plates. Silk fibroin was used as reinforcement for starch and polyvinyl alcohol (St/PVA) blends in order to improve their mechanical and water-resistance properties. The composites were plasticized with citric acid and cross-linked with gluteraldehyde. The reinforced films showed an increase in tensile strength with decrease in elongation at break. The optimized samples were characterized by scanning electron microscopy and were studied for their antibacterial properties. The biodegradable behavior was studied by the soil burial method.  相似文献   

10.
A solution-phase approach to the synthesis of nano-Se/silk fibroin colloids(NSeSFC) by reducing selenious acid solution with silk fibroin(SF) was proposed, and the composites were in situ prepared by macrowave method. The nanocomposites were characterized with ultraviolet-visible(UV-Vis) absorption spectrometry, resonance Rayleigh scattering(RRS) spectrometry and transmission electron microscopy(TEM). The nano-Se(0) solution exhibited the strongest resonance Rayleigh scattering at 579 nm. Through the RRS di...  相似文献   

11.
再生蚕丝的制备及其结构和性能初探   总被引:3,自引:0,他引:3  
在制备高浓度高分子量蚕丝素蛋白水溶液的基础上, 采用湿法纺丝技术, 在一定条件下纺制出力学性能优于天然蚕(茧)丝的再生蚕丝纤维, 其断裂强度及断裂伸长率分别达到0.5 GPa和20%. 扫描电镜观察结果显示: 初生纤维具有典型的“皮芯”结构, 而纤维内部则为疏松多孔的网状或蜂窝状结构; 经过一定的后拉伸处理后, 纤维的表面变得光滑, 且内部结构也趋于致密. 固体 13C核磁共振及拉曼光谱分析结果表明, 后拉伸及热湿处理均有利于提高纤维内部β-折叠结构的含量, 分子链的规整度和取向性也随之改善, 从而使再生蚕丝纤维的力学性能得到进一步提高.  相似文献   

12.
We have carried out studies on the rheological properties of regenerated silk fibroin (RSF) solution using video microscopy. The degummed silk from the Bombyx mori silkworm was used to prepare RSF solution by dissolving it in calcium nitrate tetrahydrate‐methanol solvent. Measurements were carried out by tracking the position of an embedded micron‐sized polystyrene bead within the RSF solution through video imaging. The time dependent mean squared displacement (MSD) of the bead in solution and hence the complex shear modulus of this solution was calculated from the bead's position information. We present here the results of rheological measurements of the silk polymer network in solution over a frequency range, whose upper limit is the frame capture rate of our camera at full resolution. By examining the distribution of MSD of beads at different locations within the sample volume, we demonstrate that this probe technique enables us to detect local inhomogeneities at nanometre length scales, not detectable either by a rheometer or from diffusing wave spectroscopy. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2555–2562, 2007  相似文献   

13.
天然蜘蛛丝是由β-sheet交联的蛛丝蛋白溶剂流入S-型导管后经牵引拉伸形成,它显示了高强度与高韧性的完美结合。其优异的力学性质主要源于它的多级结构:交联、线性排列的纳米组装体以及核壳结构。受此启发,我们合成了一种交联的水凝胶,通过牵引拉丝的方法,制备了交联的、含有取向排列的纳米组装体结构以及核壳结构的凝胶纤维,并通过少量引入二维纳米材料—氧化石墨烯(0.01%),进一步调控纳米组装体的取向和尺寸,实现了蜘蛛丝般优异的力学性能(断裂强度560 MPa,断裂韧性200 MJ·m–3,缓冲能94%)。这种纤维可以用于高速下落物体的能量耗散和降低冲击力。  相似文献   

14.
Silk fibroin is a useful protein polymer for biomaterials and tissue engineering. In this work, porogen leached scaffolds prepared from aqueous and HFIP silk solutions were reinforced through the addition of silk particles. This led to about 40 times increase in the specific compressive modulus and the yield strength of HFIP‐based scaffolds. This increase in mechanical properties resulted from the high interfacial cohesion between the silk matrix and the reinforcing silk particles, due to partial solubility of the silk particles in HFIP. The porosity of scaffolds was reduced from ≈90% (control) to ≈75% for the HFIP systems containing 200% particle reinforcement, while maintaining pore interconnectivity. The presence of the particles slowed the enzymatic degradation of silk scaffolds.

  相似文献   


15.
蚕丝蛋白与硅溶胶复合材料的研究   总被引:3,自引:2,他引:1  
程成  邵正中  陈新 《高分子学报》2008,(10):974-978
采用动态力学测试手段(DMA)并结合扫描电镜和拉曼光谱等方法,考察了用桑蚕丝蛋白与二氧化硅水分散体系(硅溶胶)制备的复合材料的结构与性质.结果表明,在此共混体系中,直径约为100 nm的二氧化硅聚集体与丝蛋白连续相的界面相容性良好.动态力学测试发现,复合材料的动态力学性能在15℃到55℃范围相对于纯丝蛋白材料得到了改善,二氧化硅组分的加入对丝蛋白分子链段的运动性有所阻碍,从而导致了40℃模量损耗的消失.  相似文献   

16.
夏友谊 《广州化学》2007,32(4):35-38
探讨了纳米TiO2在丝素溶液中的分散条件,在此基础上制备了纳米TiO2/丝素复合膜,并用原子力显微镜(AFM)和扫描电子能谱(EDS)对复合膜进行了表征。实验结果表明,制膜方法较为合理。当以有机物A为分散剂,纳米TiO2含量为1/1000时,其以粒径50 nm左右均匀地分散于复合膜中。  相似文献   

17.
莫春丽  DICKO Cedric  邵正中  陈新 《化学学报》2009,67(22):2641-2644
采用时间分辨全反射红外光谱为主要分析手段, 对醋酸在丝蛋白膜中的扩散过程及其对丝蛋白构象转变机理进行了研究. 结果表明, 醋酸能够诱导丝蛋白构象转变为β-折叠. 醋酸的扩散速率和β-折叠构象的生成速率较为相似, 表明醋酸分子渗透到丝蛋白聚集体中是破坏丝蛋白原有氢键并诱导肽链重排, 进而实现构象转变的一个先决条件. 同时, 通过比较真空干燥处理前后丝蛋白膜的实验结果, 证实了丝蛋白中的水含量是影响醋酸的扩散速度以及丝蛋白多肽链重排速度的一个重要因素.  相似文献   

18.
Neutron reflectivity (NR) measurements of ultrathin surface films (below 30 nm) composed of Bombyx mori silk fibroin protein in combination with atomic force microscopy and ellipsometry were used to reveal the internal structural organization in both dry and swollen states. Reconstituted aqueous silk solution deposited on a silicon substrate using the spin-assisted layer-by-layer (SA-LbL) technique resulted in a monolayer silk film composed of random nanofibrils with constant scattering length density (SLD). However, a vertically segregated ordering with two different regions has been observed in dry, thicker, seven-layer SA-LbL silk films. The vertical segregation of silk multilayer films indicates the presence of a different secondary structure of silk in direct contact with the silicon oxide surface (first 6 nm). The layered structure can be attributed to interfacial β-sheet crystallization and the formation of well-developed nanofibrillar nanoporous morphology for the initially deposited silk surface layers with the preservation of less dense, random coil secondary structure for the layers that follow. This segregated structure of solid silk films defines their complex nonuniform behavior in the D(2)O environment with thicker silk films undergoing delamination during swelling. For a silk monolayer with an initial thickness of 6 nm, we observed the increase in the effective thickness by 60% combined with surprising decrease in density. Considering the nanoporous morphology of the hydrophobic silk layer, we suggested that the apparent increase in its thickness in liquid environment is caused by the air nanobubble trapping phenomenon at the liquid-solid interface.  相似文献   

19.
In this work, we developed a simple and flexible method to manufacture a 3D porous scaffold based on the blend of regenerated silk fibroin (RSF) and chitosan (CS). No crosslinker or other toxic reagents were used in this method. The pores of resulted 3D scaffolds were connected with each other, and their sizes could be easily controlled by the concentration of the mixed solution. Compared with pure RSF scaffolds, the water absorptivities of these RSF/CS blend scaffolds with significantly enhanced mechanical properties were greatly increased. The results of MTT and RT-PCR tests indicated that the chondrocytes grew very well in these blend RSF/CS porous scaffolds. This suggested that the RSF/CS blend scaffold prepared by this new method could be a promising candidate for applications in tissue engineering.  相似文献   

20.
Summary: The thermal and structural analysis of silk fibroin (SF) and silk sericin (SS) blend films reveals that the crystallization of SF is retarded in the presence of SS. Although a phase separation was observed, there might be a strong interaction at the boundary of the SF and SS through intermolecular hydrogen bonding, which restricts the conformational transition of SF.

TEM image of the cross‐section of the SF/SS blend (75:25) film (magnification: ×15 000).  相似文献   


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