EDC-Crosslinked Electrospun Silk-Fibroin Fiber Mats

2011 ◽  
Vol 175-176 ◽  
pp. 170-175 ◽  
Author(s):  
Rong Liu ◽  
Feng Zhang ◽  
Bao Qi Zuo ◽  
Huan Xiang Zhang
Keyword(s):  
Silk Fibroin ◽  
Rupture Strength ◽  
Mechanical Test ◽  
Crosslinking Agent ◽  
Water Soluble ◽  
Random Coil ◽  
Crosslinking Reaction ◽  
Elongation Ratio ◽  
Silk Fibroin Fiber ◽  
Α Helix

Electrospun Silk-Fibroin (SF) mats were fabricated by electrospinning with regenerated Bombyx mori silk-fibroin/formic acid solutions. After spinning, the water soluble and mechanical properties of pure fibroin nanofibers were poor. So electrospun SF mats were crosslinked with N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC), a low cell cytotoxicity crosslinking agent, and N-hydroxysuccinimide (NHS), which can increase the reaction rate. The scanning electron microscope images indicated that the diameter of fibers increased with crosslinking reaction. When EDC/NHS reached to 7.5wt.%, the diameter of fibers achieved the maximum. The mechanical test showed that tensile strength enhanced after crosslinking with EDC/ NHS. While EDC/NHS reached to 7.5wt %, the rupture strength reached to (38.31±5.30) Mpa, and the breaking elongation ratio reached to (182.00±31.27) %. FTIR results showed the the proportion of β-sheet increased while random coil and α-helix decreased after treatment.

Raman Spectroscopic Investigation of the Denaturation Process of Silk Fibroin

1989 ◽  
Vol 43 (7) ◽  
pp. 1269-1272 ◽  
Author(s):  
Siding Zheng ◽  
Guanxian Li ◽  
Wenhuo Yao ◽  
Tongyin Yu
Keyword(s):  
Raman Spectroscopy ◽  
Silk Fibroin ◽  
Conformational Transition ◽  
Transition Process ◽  
Random Coil ◽  
Helical Conformation ◽  
Extension Rate ◽  
Α Helix ◽  
Β Sheet ◽  
Denaturation Process

The mechanical denaturation process of silk fibroin is examined by Raman spectroscopy. The fresh silk fibroins from the middle gland of mature silkworms are drawn to various ratios on a tensile tester ( R = ldrawn/ linitial, where l is length) and their conformations are measured with Raman spectroscopy. Undrawn silk fibroin is mainly in the random coil structure with some α-helical conformation, the characteristic bands appearing at 1252 and 1660 (random coil) and at 942, 1106, and 1270 cm−1 (α-helix). When the samples are drawn up to R = 4 at an extension rate of 500 mm/min, two peaks at 1233 cm−1 (the amide III band) and 1085 cm−1 appear; it is shown that the β-sheet conformation is then formed. With an increase in drawing ratios, the intensities of these β-sheet bands increase and those of the random coil and α-helical bands decrease gradually. These changes indicate that, under the action of stress, the conformation of fibroin is altered from random coil and α-helix to β-sheet structures. This result is quite similar to the results achieved by the spinning of the silkworm. The effect of the water content in liquid silk on this conformational transition process is revealed and discussed.

scholarly journals Structure Water-Solubility Relationship in α-Helix-Rich Films Cast from Aqueous and 1,1,1,3,3,3-Hexafluoro-2-Propanol Solutions of S. c. ricini Silk Fibroin

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3945
Author(s):  
Moseti ◽  
Yoshioka ◽  
Kameda ◽  
Nakazawa
Keyword(s):  
Silk Fibroin ◽  
Water Solubility ◽  
Silk Gland ◽  
Post Treatment ◽  
Water Soluble ◽  
Cast Film ◽  
Silk Glands ◽  
Α Helix ◽  
Β Sheet ◽  
Structure Water

Silk fibroin (SF) produced by the domesticated wild silkworm, Samia cynthia ricini (S. c. ricini) is attracting increasing interest owing to its unique mechanical properties, biocompatibility, and abundance in nature. However, its utilization is limited, largely due to lack of appropriate processing strategies. Various strategies have been assessed to regenerate cocoon SF, as well as the use of aqueous liquid fibroin (LFaq) prepared by dissolution of silk dope obtained from the silk glands of mature silkworm larvae in water. However, films cast from these fibroin solutions in water or organic solvents are often water-soluble and require post-treatment to render them water-stable. Here, we present a strategy for fabrication of water-stable films from S. c. ricini silk gland fibroin (SGF) without post-treatment. Aqueous ethanol induced gelation of fibroin in the posterior silk glands (PSG), enabling its separation from the rest of the silk gland. When dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), the SGF-gel gave a solution from which a transparent, flexible, and water-insoluble film (SGFHFIP) was cast. Detailed structural characterization of the SGFHFIP as-cast film was carried out and compared to a conventional, water-soluble film cast from LFaq. FTIR and 13C solid-state NMR analyses revealed both cast films to be α-helix-rich. However, gelation of SGF induced by the 40%-EtOH-treatment resulted in an imperfect β-sheet structure. As a result, the SGF-gel was soluble in HFIP, but some β-sheet structural memory remains, and the SGFHFIP as-cast film obtained has some β-sheet content which renders it water-resistant. These results reveal a structure water-solubility relationship in S. c. ricini SF films that may offer useful insights towards tunable fabrication of novel biomaterials. A plausible model of the mechanism that leads to the difference in water resistance of the two kinds of α-helix-rich films is proposed.

scholarly journals FORMULATION, DEVELOPMENT AND CHARACTERIZATION OF DRUG DELIVERY SYSTEMS BASED TELMISARTAN ENCAPSULATED IN SILK FIBROIN NANOSPHERE’S

2019 ◽  
Vol 11 (1) ◽  
pp. 247 ◽  
Author(s):  
Shahid Ud Din Wani ◽  
Gangadharappa H. V. ◽  
Ashish N. P.
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Zeta Potential ◽  
Silk Fibroin ◽  
Drug Delivery Systems ◽  
Delivery Systems ◽  
Water Soluble ◽  
Random Coil ◽  
Burst Release

Objective: The aim of the present work was to formulate silk fibroin (SF) nanospheres (NS’s) for drug delivery application. The current study was designed to advance the water solubility and bio-availability of telmisartan by nanoprecipitation method.Methods: SF NS’s loaded with TS were prepared by nanoprecipitation method. The drug was dissolved in aqueous solution of SF by using acetone as a non-solvent. The prepared NS’s were then characterized by FTIR, X-ray diffraction and zeta potential, and were evaluated for its, surface morphology, %drug content, encapsulation efficiency and in vitro drug release.Results: The evaluation results of SF NS’s loaded of TS showed 74.22±0.17 % entrapment efficiency, 35.21±0.02 % of drug loading, and-4.9 mV to-13.6 mV of zeta potential due to the proper bounding of TS with the β-sheets of SF, the particle size reported was within the size range of 160-186 nm having smooth surface and were spherical in shape. The SFNS’s pattern switched from random coil to β-sheet formation on treating with acetone. FTIR and DSC studies marked no such inter-molecular interactions between SF and drug molecules. The % cumulative in vitro drug release from SF NS’s exhibited quick burst release. The in vitro cumulative drug release of SF NS’s of TS it was found that about 74% of the drug was released within 8 h and about 96% of drug released at 24 hr. The rate of drug release increased with the increase in SF ratio.Conclusion: It is believed that these SF NS’s will find potential applications in drug delivery release as drug carriers, especially poor water-soluble drugs. All these results proposed that SF NS’s are eventuality handy in various drug delivery systems.

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.

Ultrasonication-Induced Rapid Gelation of Wild Silkworm Silk Fibroins

2013 ◽  
Vol 634-638 ◽  
pp. 1165-1169 ◽  
Author(s):  
Gui Yang Liu ◽  
Si Yong Xiong ◽  
Ren Chuan You ◽  
Ling Shuang Wang ◽  
Ming Zhong Li
Keyword(s):  
Secondary Structure ◽  
Silk Fibroin ◽  
Gelation Time ◽  
Random Coil ◽  
X Ray Diffraction ◽  
Freeze Dried ◽  
Silk Fibroins ◽  
Wild Silkworm ◽  
Α Helix ◽  
Silkworm Silk

Silk fibroin （SF） hydrogels of the wild silkworm species Antheraea pernyi and Antheraea yamamai were obtained from aqueous SF solutions at room temperature. Both A. pernyi and A. yamamai solutions were slow to gelate. Hydrogels of the two species of wild silkworm were obtained rapidly following ultrasonicaton at 400–500 W. The secondary structure of the freeze-dried SF hydrogels was measured by X-ray diffraction and Fourier transform infrared spectroscopy. Ultrasonication did not change the main secondary structure of the hydrogels, but it accelerated the structural transformation of silk fibroin molecules from random coil or α helix to β sheet and reduced the gelation time.

Study on Antheraea Pernyi Silk Fibroin Porous Materials

2011 ◽  
Vol 332-334 ◽  
pp. 1718-1721
Author(s):  
Li Mao ◽  
Xi Long Wu ◽  
Yu Liu ◽  
Shen Zhou Lu
Keyword(s):  
Porous Materials ◽  
Silk Fibroin ◽  
Average Pore Size ◽  
Diffraction Method ◽  
Random Coil ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Antheraea Pernyi ◽  
Thiocyanate Solution ◽  
Α Helix

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.

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.

Preparation of Water-Insoluble Antheraea Pernyi Silk Fibroin Films

2012 ◽  
Vol 569 ◽  
pp. 311-315 ◽  
Author(s):  
Shen Zhou Lu ◽  
Li Mao ◽  
Yu Liu ◽  
Shan Sun ◽  
Gui Jun Li
Keyword(s):  
Silk Fibroin ◽  
Diffraction Method ◽  
Random Coil ◽  
X Ray Diffraction ◽  
Antheraea Pernyi ◽  
Blend Film ◽  
Blend Films ◽  
Thiocyanate Solution ◽  
Α Helix ◽  
Β Sheet

Antheraea pernyi silk fibroin (ASF) solution was prepared by dissolving Antheraea pernyi silk fiber in lithium thiocyanate solution. The ASF/glycol blend films were prepared by casting aqueous solution of ASF mixed with glycol. The structure of blend film was investigated by the X-ray diffraction method and infrared spectroscopy. The result showed that the structure of regenerated ASF film was α-helix and random coil conformation. After mixing with glycol, it resulted in significant increase in β-sheet structure with the improvement of water resistance of the films. This effect was strongly dependent on glycol content in the blend film. When the glycol content was more than 45 wt%, the structure of ASF changed to β-sheet and the film became water-insoluble. The breaking strength and elongation of ASF/glycol blend film were 30 Mpa and 50 %, respectively. In summary, the ASF/glycol blend film provided a great potential as a biological material.

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.

scholarly journals Preparation of silk fibroin microspheres by emulsificationdiffusion method for controlled release drug delivery applications

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Thanonchat Imsombut ◽  
Mangkorn Srisa-ard ◽  
Prasong Srihanam ◽  
Yodthong Baimark
Keyword(s):  
Drug Release ◽  
Silk Fibroin ◽  
Drug Loading ◽  
Water Soluble ◽  
Random Coil ◽  
Diffusion Method ◽  
Surface Erosion ◽  
Erosion Processes ◽  
Release Drug ◽  
Model Drug

AbstractSilk fibroin (SF) microspheres containing a model drug were prepared by a simple water-in-oil emulsification-diffusion method. Aqueous SF solution and ethyl acetate were used as water and oil phases, respectively. Methylene Blue was used as a water-soluble model drug. Effect of drug content on microsphere characteristics, drug loading efficiency and drug release behavior was determined. Scanning electron microscopy revealed that drug-loaded SF microspheres were spherical in shape with a smooth surface. The SF microspheres showed predominant random coil SF conformation. All drug loading efficiencies were approximately 50%. An increase in drug/SF ratio could lead to an increase in %drug release and surface erosion after the drug release test. Drug release from SF microspheres is due to SF matrix swelling and surface erosion processes.

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