Preparation of Silk Fibroin Microspheres

2011 ◽  
Vol 236-238 ◽  
pp. 1902-1905 ◽  
Author(s):  
Lu Wang ◽  
Zhen Ran Xia ◽  
Lin Lin Lv ◽  
Qiang Tang ◽  
Ming Zhong Li
Keyword(s):  
Silk Fibroin ◽  
Flow Rate ◽  
Molecular Conformation ◽  
Solution Concentration ◽  
Random Coil ◽  
Ethanol Treatment ◽  
Drying Method ◽  
Sphere Size ◽  
Ft Ir ◽  
Fibroin Solution

TheBombyx morisilk fibroin microspheres with controllable size were prepared by electrostatic spraying and freeze-drying method. The effects of solution concentration, voltage and flow rate on the sphere size were discussed. The morphology of microspheres was observed by scanning electron microscopy (SEM). The influence of ethanol treatment on the molecular conformation of silk fibroin microspheres was investigated by XRD and FT-IR spectra. The results indicated that the silk fibroin microspheres with diameter in range of 117-363 μm were spherical in shape, and there were plenty of pores both on the surface and in the interior of the microspheres. The sphere size increased with the rising of silk fibroin solution concentration and flow rate, while decreased as the voltage enhanced. The conformation of silk fibroin microspheres changed from random coil to silk II structure after ethanol treatment.

Comparison of Porosity Improvement of Silk Fibroin Membrane Using Polyethylene Glycol and Glutaraldehyde for Increasing Oxygen Permeability

2013 ◽  
Vol 750-752 ◽  
pp. 1601-1608
Author(s):  
Pacharawan Ratanasongtham ◽  
Ruangsri Watanesk ◽  
Surasak Watanesk
Keyword(s):  
Polyethylene Glycol ◽  
Silk Fibroin ◽  
Oxygen Permeability ◽  
Porous Membrane ◽  
Swelling Behavior ◽  
Random Coil ◽  
Environmental Friendliness ◽  
Ft Ir ◽  
Water Swelling ◽  
Β Sheet

Biomaterial is one of the good candidates for porous membrane preparation according to its environmental friendliness. In this work, the porous membranes of silk fibroin (SF) were prepared by solution casting with the addition of polyethylene glycol (PEG) and glutaraldehyde (GTA) aiming to improve the porosity and oxygen permeability of SF membrane. The conformation of SF was changed from random coil to β sheet form after treatment with MeOH. The interaction existing between SF chains and both PEG and GTA were characterized using Fourier Transform Infrared spectroscopy (FT-IR). The addition of PEG could produce more porosity in the membrane than GTA confirmed by their morphology observed from scanning electron microscopy (SEM). Moreover, the swelling behavior of the SF-PEG and SF-GTA membranes depended on the porous structure of the membrane which directly correlated to their oxygen permeability. The porosity of the SF membranes increased with the increase of PEG and GTA contents up to 40% and 3%w/w, respectively. After that, their porosity decreased as seen through the SEM and water swelling results. In addition, the SF-PEG membrane turned out to have higher degrees of both porosity and oxygen permeability than the SF-GTA membrane which related to its water swelling behavior.

EFFECT OF STORAGE TIME AND CONCENTRATION ON STRUCTURE OF REGENERATED SILK FIBROIN SOLUTION

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3878-3883 ◽  
Author(s):  
FANG XIE ◽  
HUILI SHAO ◽  
XUECHAO HU
Keyword(s):  
Aqueous Solution ◽  
Silk Fibroin ◽  
Storage Time ◽  
Conformational Transition ◽  
Solution Concentration ◽  
Cd Spectroscopy ◽  
Random Coil ◽  
Conformational Transformation ◽  
Regenerated Silk Fibroin ◽  
Α Helix

Concentrated regenerated silk fibroin (RSF) aqueous solutions with concentration close to that of the native silk fibroin (15.5%, 25.5% and 31%) were prepared. The effect of storage time and concentration on the conformational transition of the concentrated RSF aqueous solution was studied by Raman spectroscopy and circular dichroism (CD) spectroscopy. At the same time, the conformational change of RSF aqueous solution in flowing state was also investigated. It was found that the conformation of silk fibroin was changed gradually from random coil/α-helix to β-sheet structure during the storage. And the conformational transformation was accelerated with the increasing of the RSF aqueous solution concentration. When the solution was in flowing state, the conformational transformation was also accelerated.

scholarly journals Control of the gelation process of silk fibroin solution

2014 ◽  
Vol 18 (5) ◽  
pp. 1587-1590 ◽  
Author(s):  
Yu Liu ◽  
Ying Zhang
Keyword(s):  
Bombyx Mori ◽  
Silk Fibroin ◽  
Conformational Transition ◽  
Random Coil ◽  
Simple Shearing ◽  
Gelation Process ◽  
Bombyx Mori Silk ◽  
Fibroin Solution

In the present study, silk fibroin solution was controlled through a simple shearing to accomplish the steady and rapid gelation process and the conformational transition. Antheraea yamamai silk fibroin was formed into hydrogels quicker than Bombyx mori silk fibroin on the same condition. Comparing with Bombyx mori silk fibroin, the rapid gelation of Antheraea yamamai silk fibroin was concerned with its alternate polyalanine-containing units which are tended to form the ?-helix structures spontaneously. The entropic cost during the conformational transition to ?-sheet is less than that from random coil to ?-sheet.

Effect of Concentration on Structure and Properties of Concentrated Regenerated Silk Fibroin Solution

2011 ◽  
Vol 311-313 ◽  
pp. 1653-1656 ◽  
Author(s):  
Fang Xie ◽  
Hao Liang
Keyword(s):  
Silk Fibroin ◽  
Conformational Transition ◽  
Random Coil ◽  
Scanning Calorimetry ◽  
Regenerated Silk Fibroin ◽  
Lower Temperature ◽  
Α Helix ◽  
Β Sheet ◽  
Dsc Curves ◽  
Fibroin Solution

The thermal properties and rheological behavior of concentrated regenerated silk fibroin aqueous solution from 15% to 37% was investigated by differential scanning calorimetry (DSC) and rheometer. Also the conformation of solutions was characterized by Raman spectra. It was discovered that the major endothermic peak in the DSC curves shifted toward the lower temperature region with increasing the concentration. This behavior suggests increasing the concentration can accelerate conformational transition of silk fibroin from random coil and α-helix to β-sheet structure. In addition, it was found that the viscosity of solution increased with increasing concentration in favor of spinning.

Effects of Gamma Irradiation on the Structure and Mechanical Properties of Wild Silkworms and Bombyx Mori Silk Fibroin Films

2011 ◽  
Vol 197-198 ◽  
pp. 27-31 ◽  
Author(s):  
Si Yong Xiong ◽  
Ya Mei Xu ◽  
Yu Hong Jiao ◽  
Lu Wang ◽  
Ming Zhong Li
Keyword(s):  
Mechanical Properties ◽  
Gamma Irradiation ◽  
Silk Fibroin ◽  
Gamma Ray ◽  
Molecular Conformation ◽  
Covalent Bonds ◽  
Secondary Bonds ◽  
Aggregation Structure ◽  
Bombyx Mori Silk ◽  
Ft Ir

The structure and mechanical properties of A. yamamai, A. perny and B. mori silk fibroin films irradiated by gamma ray with various doses of 0, 25, 50, 100 and 200 kGy, respectively were determined by XRD, FT-IR, DSC and Instron 3365 equipment. Results showed that the aggregation structure and molecular conformation of A. yamamai, A. perny and B. mori silk fibroin films irradiated by gamma ray with those doses mentioned above were not significantly changed. However, with the increase of radiation intensity, the thermal stability of silk fibroin films declined slightly, and the breaking strength and extensibility reduced significantly, due to the breakdown of parts of secondary bonds and covalent bonds. These results suggested that, when these silk fibroin materials were sterilized by gamma irradiation, smaller radiation doses should be used, otherwise irreversible damages on these materials would be caused.

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.

Controlling molecular conformation of regenerated wild silk fibroin by aqueous ethanol treatment

2003 ◽  
Vol 14 (10) ◽  
pp. 694-698 ◽  
Author(s):  
Mingzhong Li ◽  
Wei Tao ◽  
Shigenori Kuga ◽  
Yoshiharu Nishiyama
Keyword(s):  
Silk Fibroin ◽  
Molecular Conformation ◽  
Aqueous Ethanol ◽  
Ethanol Treatment

Effect of Polymeric Additives on Turbulent Flow in Opposed Jets

1995 ◽  
Vol 48 (11S) ◽  
pp. S216-S221 ◽  
Author(s):  
A. J. Mu¨ller ◽  
A. E. Saez ◽  
J. P. Tatham ◽  
J. A. Odell
Keyword(s):  
Pressure Drop ◽  
Turbulent Flow ◽  
Flow Rate ◽  
Molecular Conformation ◽  
Rate Of Change ◽  
Newtonian Fluids ◽  
Transition To Turbulence ◽  
Random Coil ◽  
Polymer Addition ◽  
Polymeric Additives

In this work we study the effect of polymeric additives on the transition to turbulence in opposed-jets flow. In this type of flow, the transition to turbulence for Newtonian fluids is characterized by a decrease in the rate of change of pressure drop with flow rate. We have used various polymers whose equilibrium molecular conformation in aqueous solution is different: poly (ethylene oxide), which exists in a conformation close to a random coil, hydroxypropyl guar, which adopts an expanded coil conformation, and hydrolyzed polyacrylamide, whose conformation is close to a random coil in the presence of an electrolyte (sodium chloride) but it changes to an expanded coil in distilled water. The results show that small amounts of either flexible or semi-rigid polymers induce a delay in the critical Reynolds number at which turbulence sets in. This delay seems to be a result of the suppression of flow instabilities in a region close to the stagnation point, which is linked to macromolecular orientation. Since, for Newtonian fluids, this flow has an increase of drag with flow rate that is slower in the turbulent flow regime than in the laminar regime, the addition of polymer causes a substantially higher pressure drop in turbulent flow with respect to that of the pure solvent. Therefore, polymer addition causes, in this particular case, a drag increase in turbulent flow, as opposed to the commonly observed drag reduction in turbulent flow through pipes.

Preparation of Small-Diameter Silk Fibroin Tubular Scaffolds with Electrospinning Method

2013 ◽  
Vol 745-746 ◽  
pp. 1-5
Author(s):  
Jing Xin Zhu ◽  
Yan Long Ma ◽  
Tetsuo Asakura
Keyword(s):  
Silk Fibroin ◽  
Fiber Diameter ◽  
Small Diameter ◽  
Electrospun Nanofibers ◽  
Random Coil ◽  
Diameter Distribution ◽  
Ethanol Treatment ◽  
Regenerated Silk Fibroin ◽  
Tubular Scaffold ◽  
Mandrel Diameter

In recent years, electrospinning has received much attention to prepare porous tubular scaffold due to electrospun nanofibers mat, which can mimic the structure characteristics of the extracellular matrix (ECM). In the present paper, silk fibroin (SF) tubular scaffolds with small-diameter were prepared by electrospinning from regenerated silk fibroin (RSF) aqueous solutions with rotating mandrel collector. The morphology and fiber diameter distribution of SF tubular scaffolds were influenced much by the concentration of regenerated silk fibroin (RSF) solution, collecting distance and mandrel diameter. The results showed that SF tubular scaffold, which was in flat surface with smaller fiber diameter and uniform distributed, could be obtained at the concentration of 22%, collection distance of 10 cm and mandrel diameter of 4 mm. The structure of SF tubular scaffolds before and after ethanol treatment was characterized by FTIR and XRD. After ethanol treatment, the SF tubular scaffolds had a conformation transition from random-coil conformation to Silk II conformation.

scholarly journals Chitosan hydrogel/silk fibroin/Mg(OH)2 nanobiocomposite as a novel scaffold with antimicrobial activity and improved mechanical properties

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Reza Eivazzadeh-Keihan ◽  
Fateme Radinekiyan ◽  
Hooman Aghamirza Moghim Aliabadi ◽  
Sima Sukhtezari ◽  
Behnam Tahmasebi ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Cell Viability ◽  
Silk Fibroin ◽  
Analytical Techniques ◽  
Structural Features ◽  
Mechanical Tests ◽  
Chitosan Hydrogel ◽  
Biological Capacity ◽  
Ft Ir ◽  
Novel Scaffold

AbstractHerein, a novel nanobiocomposite scaffold based on modifying synthesized cross-linked terephthaloyl thiourea-chitosan hydrogel (CTT-CS hydrogel) substrate using the extracted silk fibroin (SF) biopolymer and prepared Mg(OH)2 nanoparticles was designed and synthesized. The biological capacity of this nanobiocomposite scaffold was evaluated by cell viability method, red blood cells hemolytic and anti-biofilm assays. According to the obtained results from 3 and 7 days, the cell viability of CTT-CS/SF/Mg(OH)2 nanobiocomposite scaffold was accompanied by a considerable increment from 62.5 to 89.6% respectively. Furthermore, its low hemolytic effect (4.5%), and as well, the high anti-biofilm activity and prevention of the P. aeruginosa biofilm formation confirmed its promising hemocompatibility and antibacterial activity. Apart from the cell viability, blood biocompatibility, and antibacterial activity of CTT-CS/SF/Mg(OH)2 nanobiocomposite scaffold, its structural features were characterized using spectral and analytical techniques (FT-IR, EDX, FE-SEM and TG). As well as, given the mechanical tests, it was indicated that the addition of SF and Mg(OH)2 nanoparticles to the CTT-CS hydrogel could improve its compressive strength from 65.42 to 649.56 kPa.

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