Preparation and Characterization of Silk Fibroin/Hydroxyapatite Bilayer Scaffolds

2011 ◽  
Vol 415-417 ◽  
pp. 1810-1815 ◽  
Author(s):  
Jian Bing Liu ◽  
Qiang Tang ◽  
Shen Zhou Lu ◽  
Ceng Zhang ◽  
Ming Zhong Li
Keyword(s):  
Silk Fibroin ◽  
Electron Excitation ◽  
Mouse Bone Marrow ◽  
High Porosity ◽  
X Ray Diffraction ◽  
Tissue Engineering Scaffolds ◽  
Molding Method ◽  
Isostatic Compaction ◽  
Fibroin Solution

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.

scholarly journals Fabrication and Characterization of Electrospun Polycaprolactone Blended with Chitosan-Gelatin Complex Nanofibrous Mats

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Yongfang Qian ◽  
Zhen Zhang ◽  
Laijiu Zheng ◽  
Ruoyuan Song ◽  
Yuping Zhao
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Weight Ratio ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Tissue Engineering Scaffolds ◽  
Elongation At Break ◽  
Nanofibrous Scaffolds ◽  
Two Peaks

Design and fabrication of nanofibrous scaffolds should mimic the native extracellular matrix. This study is aimed at investigating electrospinning of polycaprolactone (PCL) blended with chitosan-gelatin complex. The morphologies were observed from scanning electron microscope. As-spun blended mats had thinner fibers than pure PCL. X-ray diffraction was used to analyze the degree of crystallinity. The intensity at two peaks at 2θof 21° and 23.5° gradually decreased with the percentage of chitosan-gelatin complex increasing. Moreover, incorporation of the complex could obviously improve the hydrophilicity of as-spun blended mats. Mechanical properties of as-spun nanofibrous mats were also tested. The elongation at break of fibrous mats increased with the PCL content increasing and the ultimate tensile strength varied with different weight ratios. The as-spun mats had higher tensile strength when the weight ratio of PCL to CS-Gel was 75/25 compared to pure PCL. Both as-spun PCL scaffolds and PCL/CS-Gel scaffolds supported the proliferation of porcine iliac endothelial cells, and PCL/CS-Gel had better cell viability than pure PCL. Therefore, electrospun PCL/Chitosan-gelatin nanofibrous mats with weight ratio of 75/25 have better hydrophilicity mechanical properties, and cell proliferation and thus would be a promising candidate for tissue engineering scaffolds.

Optimizing Performance of ZnO Nanorod and Activated Carbon as a Composite Anode for Lithium-Ion Batteries

2020 ◽  
Vol 1000 ◽  
pp. 31-40
Author(s):  
Bambang Priyono ◽  
Ananta Riezky Bachtiar ◽  
Hugo Abraham ◽  
Mohammad Ridho Nugraha ◽  
Faizah ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Electrochemical Impedance ◽  
Zno Nanorods ◽  
Specific Capacity ◽  
Lithium Ion ◽  
High Porosity ◽  
Composite Anode ◽  
X Ray Diffraction ◽  
Stable Performance

To obtain the high specific capacity anode for Lithium-ion battery with stable performance is conducted by synthesizing a composite anode of ZnO-nanorods (ZnO-NR) and as a matrix is the activated carbon (AC). In this study, ZnO-NR synthesized a process that uses basic materials hexamethylenetetramine (HMTA) and zinc oxide. Activated carbon has been activated because it has high porosity and good electrical conductivity properties. Variable used is the percentage of ZnO-NR, which is 30wt%, 40wt%, and 50wt%. Characterization of the samples was examined using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Brunauer–Emmett–Teller (BET). The battery performance of the samples was obtained by Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV), and Charge-Discharge (CD) testing after being assembled into coin cell batteries. This study discusses the effect of adding activated carbon to ZnO NR composites. The results showed that the ZnO-NR30/AC has the highest specific capacity of 270.9 mAh g-1. According to Brunner-Emmet-Teller (BET) test, the largest surface area was 631.685 m2 g-1. Electrochemical performance is the best obtained by ZnO-NR30/AC.

Preparation and Characterization of Silk Fibroin/Calcium Phosphate Composite

2011 ◽  
Vol 332-334 ◽  
pp. 1655-1658
Author(s):  
Biao Wang ◽  
Rui Juan Xie ◽  
Yang Yang Huang
Keyword(s):  
Compressive Strength ◽  
Calcium Phosphate ◽  
Silk Fibroin ◽  
Solid Phase ◽  
Setting Time ◽  
Testing Machine ◽  
X Ray Diffraction ◽  
Acicular Crystal ◽  
Setting Times

In this paper, calcium phosphate cement (CPC) was prepared with tetracalcium phosphate (TTCP)/dicalcium phosphate anhydrous (DCPA) system as solid phase and phosphate buffered solution (PBS) as liquid phase, then silk fibroin (SF) was added into CPC to form silk fibroin/calcium phosphate composite. To study the effect of SF on the properties of composite, different mass fraction of SF was added into the composite. The surface morphology was observed by Scanning Electron Microscope. The setting time was investigated by ISO Cement Standard Consistency Instrument. The structure of the composite was studied by X-ray diffraction and infrared spectroscopy. Mechanical properties of samples were tested by Instron Universal Testing Machine. The results showed that the particles of SF could be seen obviously in the surface of all composite, and acicular crystal of hydroxyapatite (HA) was formed in the hardening body of both the composite and the pure CPC. The acicular crystal of HA derived from composite with SF appeared to be thinner. The setting times of the composites were all between 9 to 15min. Compared to pure CPC, the compressive strength and work-of-compressive of composites were all improved. The compressive strength of the composite with 1% SF increased obviously.

scholarly journals Mineralogical and Chemical Characterization of Bajrawia Iron Ore, Sudan

2019 ◽  
Vol 8 (1) ◽  
pp. 8-14
Author(s):  
Ahmed Mohammedelmubarak Abbaker ◽  
Eltahir Mohamed Moslim ◽  
Montasir Sabbah El Din Elsalmawy
Keyword(s):  
Iron Ore ◽  
Chemical Characterization ◽  
High Porosity ◽  
Rock Matrix ◽  
X Ray Diffraction ◽  
Mineralogical Characterization ◽  
X Ray ◽  
Iron Mineral ◽  
Fluorescence Energy

In this contribution, the mineralogical and chemical characterization of Bajrawia iron ore is investigated. The chemical analysis was conducted using atomic absorption spectroscopy, X-ray Fluorescence, Energy Dispersive X-ray and titration. The mineralogical characterization was obtained by optical microscopy and X-ray diffraction. The physical properties such as densities, water content and porosity were determined. It was found that Bajrawia iron ore contains about 35.5% Fe and some impurities like phosphorus and silica. Goethite is the major iron mineral associated with minor contents of hematite, kaolinite and quartz. SEM photo showed that the main minerals are goethite, clay minerals and quartz. The ore has low density because it has high porosity degree. This type of iron ore is disseminated in rock matrix and would be difficult to process.

Preparation and Characterization of the Porous Hydroxyapatite/Silk Fibroin Composite Scaffolds with Interconnected Ducts

2008 ◽  
Vol 368-372 ◽  
pp. 1190-1193 ◽  
Author(s):  
Jing Wang ◽  
Mu Qin Li ◽  
Xiang Cai Meng ◽  
Guang Wu Wen
Keyword(s):  
Compressive Strength ◽  
Silk Fibroin ◽  
Freeze Drying ◽  
Composite Scaffold ◽  
Drying Process ◽  
X Ray Diffraction ◽  
Composite Scaffolds ◽  
Porous Hydroxyapatite ◽  
X Ray

Porous hydroxyapatite (HA) bioceramic matrix with interconnected ducts was obtained using a porogen burnout technique at 1200°C. The HA/silk fibroin (SF) composite scaffolds were developed with the SF sponges formed inside the pores and ducts of the bioceramics by first introducing HA/SF slurries into the pores and ducts followed by a freeze-drying process. Phase components and morphology of materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Porosity was measured by Archimedean method. Compressive strength was also measured. The simulated body fluids (SBF) experiments were conducted to evaluate bioactivity. The results show that hydroxyapatite is the main phase compositions after sintering at 1200°C. The porosity of composite scaffolds reaches 70%~80%. The sizes of pores and ducts of HA matrix range from 150μm to 400μm and the pore sizes of SF sponges formed inside the macroporous structure of bioceramics are approximately 100μm,a structure favorable for bone tissue in-growth. The compressive strength of the composite scaffolds is greatly improved in comparison with that of HA matrix. In the SBF tests, a layer of randomly oriented apatite crystals form on the scaffold surface after sample immersion in SBF. The cell culture experiments show that the osteoblast cells are attached and proliferated on the surface of the composite scaffold, which suggest good bioactivity and cellular compatibility of the composite material.

Preparation of Silk Fibroin/Bacterial Cellulose Composite Films and their Mechanical Properties

2007 ◽  
Vol 342-343 ◽  
pp. 741-744 ◽  
Author(s):  
Rira Jung ◽  
Hyoung Joon Jin
Keyword(s):  
Mechanical Properties ◽  
Bacterial Cellulose ◽  
Silk Fibroin ◽  
Composite Films ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Individual ◽  
Fibroin Solution ◽  
Cellulose Composite

We prepared composite films consisting of two biocompatible materials, bacterial cellulose and silk fibroin. Aqueous silk fibroin solution and bacterial cellulose excreted by Acetobacter xylinum were used to fabricate the composite films. It was verified by field emission scanning electron microscopy and X-ray diffraction that the two components were finely blended and that the silk fibroin was crystallized during the composition of the films. The silk fibroin penetrated well between the individual fibrils of the bacterial cellulose, while the water molecules inside the pellicular bacterial cellulose were evaporating. The composite films did not dissolve in water due to the crystallization of the silk fibroin in the composite films. We also observed the change in the mechanical properties of the composite films according to the water content. The composite films became more flexible and tougher when they were dipped in water, whereas they were very brittle in the dehydrated state.

Study on Tissue Engineering Scaffolds of Silk Fibroin-Chitosan/ Nano-Hydroxyapatite Composite

2007 ◽  
Vol 330-332 ◽  
pp. 971-975 ◽  
Author(s):  
Guang Wu Wen ◽  
Jing Wang ◽  
Mu Qin Li ◽  
Xiang Cai Meng
Keyword(s):  
Tissue Engineering ◽  
Silk Fibroin ◽  
Porous Scaffolds ◽  
High Porosity ◽  
Tissue Engineering Scaffolds ◽  
Component Structure ◽  
X Ray ◽  
Hydroxyapatite Composite ◽  
Ray Diffusion ◽  
Interconnected Pores

The porous scaffolds of silk fibroin-chitosan /nano-hydroxyapatite (SF-CS / n-HA) were fabricated through the freeze- drying technique. Component, structure and morphology of scaffolds were studied by infrared (IR), X-ray diffusion (XRD) and scanning electron microscope (SEM), and the mechanical properties of the scaffolds were measured. The simulated body fluid (SBF) experiments were conducted to assess the bioactivity of the scaffolds. Results indicate that chemical binding is formed between HA and organics, the macropore diameter of the scaffolds varies from 150 to 400μm. The porous scaffolds with interconnected pores possess a high porosity of 78%-91% and compressive strength of 0.26 -1.96MPa, which can be controlled by adjusting the concentration of organic phases and prefreezing temperature. In the SBF tests, a layer of randomly oriented bone-like apatite crystals formed on the scaffold surface, which suggested that the composite material had good bioactivity. Studies suggest the feasibility of using SF-CS /n-HA composite scaffolds for bone tissue engineering.

Study on Silk Fibroin Gelation: Effect of Polyalcohol

2011 ◽  
Vol 175-176 ◽  
pp. 137-142 ◽  
Author(s):  
Qiang Zhang ◽  
Ying Dong Cheng ◽  
Yu Liu ◽  
Shu Qin Yan ◽  
Ming Zhong Li
Keyword(s):  
Silk Fibroin ◽  
Three Dimensional ◽  
Random Coil ◽  
X Ray Diffraction ◽  
Polyethylene Glycol 400 ◽  
Bombyx Mori Silk ◽  
Α Helix ◽  
Β Sheet ◽  
Important Form ◽  
Fibroin Solution

The Bombyx mori silk fibroin gel with three dimensional structures is an important form to be developed for tissue engineering materials. In this paper, silk fibroin gels were prepared with adding polyalcohol into silk fibroin solution. The gel structure was analyzed by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. The results demonstrated that when adding more than 100% of polyalcohol, both of glycerol and polyethylene glycol 400 (PEG400) can accelerate the gelation process markedly. With the increase of the percentage of PEG400 and glycerol, it promoted silk fibroin molecules to cluster rapidly and inhibit silk fibroin molecules transforming from the random coil or α-helix to β-sheet in a ratio of 900% especially. Silk fibroin gels containing 100% of polyalcohol had more uniform morphology and the pores distributed uniformly.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

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