Authors: Shen Zhou Lu, Ming Zhong Li, Lun Bai
Abstract: The complex porous materials, Hydroxyapatite(HA)/silk fibroin, were prepared using
ultrasonic vibration gel method in this paper. The mechanical properties decreased with the increase
of HA while the porosity increased. The pore size become bigger than 100μm when adding silk fiber
in the complex materials, and the breaking energy increased evidently from 10 to 1000 J/m2 when
fiber content increased from 0 to 4 wt.%. It was observed from SEM that all composites have
interconnected micropores.
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Authors: Yi Yu Wang, Ying Dong Cheng, Yu Liu, Hui Jing Zhao, Ming Zhong Li
Abstract: Silk fibroin hydrogels is an important morphous of biomaterial. As a natural protein collosol, purified native silk fibroin solution can be gelatinized under certain conditions. The main mechanism of the gelation is that the fibroin molecules turn into the β-sheet conformation from the random coils. This transformation of silk fibroin molecules would be influenced by various parameters such as the temperature, pH value, ion concentration and so on. In this paper, the effect of ultrasonication on the gelation velocity and structure of silk fibroin were discussed. It is believed that the cavitations caused by sonication could accelerate the process of gelation of silk fibroin. Our experiments demonstrated that the ultrasonic treatment could greatly reduce the silk fibroin gelation time, especially at a high sonication power exceeding 400W. The results of XRD, FTIR, and Raman spectra indicated that the ultrasonication had no significant effect on the final structure and composition of the silk fibroin gels except the acceleration for the molecular transition from random coil and α-structure to β-sheet conformation of silk fibroin. The SEM images showed freeze-dried fibroin gels close to the ultrasonication source had compact structure, while the structure was more loosening far away to the source.
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Authors: Zhen Ran Xia, Miao Liang Luo, Qin Zhang, Jing Qu, Ming Zhong Li
Abstract: In order to investigate the effects of addition amount, particle size distribution and aver- age particle size of NaCl porogen on the pore connectivity of silk fibroin (SF) / hydroxyapatite (HA) porous composites. In this paper, the SF/HA composites were fabricated by means of isostatic pressing. The pore structure of SF/HA porous composites was observed by Scanning electron microscopy (SEM), and the air permeability was tested by home-made device. Results indicated that the larger addition amount of NaCl particles, the greater scope of NaCl particles size distribution and increased the average particle size of NaCl particles were able to make the pore connectivity of the material improved significantly. The materials with good pore connectivity, which were conducive to the immigration and adhesion of bone repair cells, information transmission and exchange with the outside tissue, and also benefit for bone tissue regeneration.
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Authors: Li Mao, Xi Long Wu, Yu Liu, Shen Zhou Lu
Abstract: Antheraea pernyi silk fibroin (ASF) solution was prepared by dissolving Antheraea pernyi silk fiber in lithium thiocyanate solution. The ASF/1,4-butanediol (ASF/BDO) blend porous materials were prepared with freeze-drying method. The structure of ASF was investigated by the X-ray diffraction method. The result showed that the structure of regenerated ASF scaffold was α-helix and random coil conformation. After ASF mixed with 5 wt% BDO, the structure of ASF was changed to β-sheet and the ASF scaffolds became water-insoluble. There were some small pores and fibrous structure in the big pores and the surface of pores was rough with a great many raised particles. The scaffolds with the average pore size of 300-1000μm and the porosity of 82-92% can efficiently be produced in this paper. Due to avoid the use of organic solvents or harsh chemicals, these new ASF based porous materials provide much more excellent biocompatibility and is expected to be applied to tissue regeneration scaffolds.
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Authors: Jian Bing Liu, Qiang Tang, Shen Zhou Lu, Ceng Zhang, Ming Zhong Li
Abstract: When the articular cartilage defect accompanies with the subchondral bone defect, using bilayer scaffolds which can integrate with surrounding host cartilage and bone tissue respectively as the tissue engineering scaffolds will be conducive to the repair of tissue defects. This paper reports a new method for preparing bilayer scaffolds. Firstly, hydroxyapatite (HA)/silk fibroin(SF) composite porous materials which have high porosity were prepared by a isostatic compaction molding method, then it was fully immersed in silk fibroin solution, and finally SF/HA bilayer scaffolds were obtained by freeze-drying. The structure of the bilayer scaffolds were investigated through scanning electron microscopy, X-ray diffraction, Fourier transform-infrared spectroscopy, electron excitation spectroscopy and electron microprobe. The results indicated that the upper layer of SF/HA bilayer scaffolds is porous SF component, the under layer is the porous HA/SF composite component and the interface of the two layer is closely connected. Furthermore, mesenchymal stem cells from mouse bone marrow were seeded into the bilayer scaffolds and the results showed that the cells had a well adhesion and growth after culturing for 3 days.
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