scholarly journals A Comparative Study on the Dissolution of Argema mimosae Silk Fibroin and Fabrication of Films and Nanofibers

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 549
Author(s):  
Hlobsile Kgomo ◽  
Somandla Ncube ◽  
Vimbai Mhuka ◽  
Temesgen Girma Kebede ◽  
Simiso Dube ◽  
...  
Keyword(s):  
Formic Acid ◽  
Silk Fibroin ◽  
Influence Of Temperature ◽  
Regenerated Silk Fibroin ◽  
Silk Fibroins ◽  
Contour Plots ◽  
Wild Silkworm ◽  
Β Sheets ◽  
Β Sheet ◽  
Central Composite

Limited studies have been done on silk fibroins of wild silkworm species owing to their relative insolubility in many solvents. In this study, the solubility of Argema mimosae wild silk fibroin in different salts (LiBr, LiCl, Ca(NO3)2, and CaCl2) dissolved in formic acid under varying temperatures was investigated. The dissolution conditions under which the solubility was optimum were optimized using a central composite design approach. The optimum range for solvation of the fibroin were visualized using contour plots. The influence of temperature and salt concentration were found to significantly influence the solvation of the fibroin. Following the successful dissolution of the fibroin, the regenerated silk fibroin solutions were cast to obtain water insoluble films which were used in investigating optimum electrospinning conditions. Average nanofiber diameters in the 110–141 nm range were obtained under optimum electrospinning conditions. The silk forms were characterized using the FTIR, TGA, XRD, and SEM to understand their properties. The investigations revealed that formic acid—salt solvents were effective in the solvation of the wild silk fibroin. Some of the dissolution conditions induced mild effects on the silk fibroin while others were harsh. Furthermore, processing to nanofibers resulted in the degradation of the β-sheets producing nanofibers rich in α-helices. However, post-treatment using methanol and water vapor were effective in restoring β-sheet crystallinity.

Effect of Solvent on the Characteristics of Electrospun Regenerated Silk Fibroin Nanofibers

2007 ◽  
Vol 342-343 ◽  
pp. 813-816 ◽  
Author(s):  
Lim Jeong ◽  
Kuen Yong Lee ◽  
Won Ho Park
Keyword(s):  
Secondary Structure ◽  
Formic Acid ◽  
Silk Fibroin ◽  
Structural Changes ◽  
Effective Means ◽  
Electrospun Nanofibers ◽  
Random Coil ◽  
Regenerated Silk Fibroin ◽  
Silk Fibroin Nanofibers ◽  
Β Sheet

Nonwoven nanofiber matrices were prepared by electrospinning a solution of silk fibroin (SF) dissolved either in formic acid or in 1,1,1,3,3,3-hexafluoro-2-isopropyl alcohol (HFIP). The mean diameter of the electrospun nanofibers prepared from SF dissolved in formic acid was 80 nm with a unimodal size distribution, which was smaller than those prepared from HFIP (380 nm). SF nanofibers were then treated with an aqueous methanol solution, and structural changes due to solvent-induced crystallization of SF were investigated using IR and 13C solid-state CP/MAS NMR spectroscopy. SF nanofibers prepared from formic acid were found to have a higher proportion of β-sheet conformations than those prepared from HFIP. Methanol treatment provided a fast and effective means to alter the secondary structure of both types of SF nanofibers from a random coil form to a β-sheet form. As demonstrated in the present study, this approach to controlling the dimensions and secondary structure of proteins using various solvents may be useful for the design and tailoring of materials for biomedical applications, especially for tissue engineering applications.

SILK FIBROIN FILMS CRYSTALLIZED BY MULTIWALLED CARBON NANOTUBES

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1807-1812 ◽  
Author(s):  
H.-S. KIM ◽  
W.-I. PARK ◽  
Y. KIM ◽  
H.-J. JIN
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Silk Fibroin ◽  
Composite Films ◽  
Tensile Modulus ◽  
Multiwalled Carbon ◽  
Regenerated Silk Fibroin ◽  
Silk Films ◽  
Β Sheet

Silk films prepared from regenerated silk fibroin are normally stabilized by β-sheet formation through the use of solvents (methanol, water etc.). Herein, we report a new method of preparing water-stable films without a β-sheet conformation from regenerated silk fibroin solutions by incorporating a small amount (0.2 wt%) of multiwalled carbon nanotubes (MWCNTs). To extend the biomaterial utility of silk proteins, forming water-stable silk-based materials with enhanced mechanical properties is essential. Scanning electron microscopy and transmission electron microscopy were used to observe the morphology of the MWCNT-incorporated silk films. The wide-angle X-ray diffraction provided clear evidence of the crystallization of the silk fibroin induced by MWCNT in the composite films without any additional annealing processing. The tensile modulus and strength of the composite films were improved by 108% and 51%, respectively, by the incorporation of 0.2 wt% of MWCNTs, as compared with those of the pure silk films. The method described in this study will provide an alternative means of crystallizing silk fibroin films without using an organic solvent or blending with any other polymers, which may be important in biomedical applications.

A comparison of centrifugally-spun and electrospun regenerated silk fibroin nanofiber structures and properties

RSC Advances ◽  
2015 ◽  
Vol 5 (119) ◽  
pp. 98553-98558 ◽  
Author(s):  
Chen Liu ◽  
Jiaqi Sun ◽  
Min Shao ◽  
Bin Yang
Keyword(s):  
Thermal Properties ◽  
Silk Fibroin ◽  
Secondary Structures ◽  
Random Coil ◽  
Structures And Properties ◽  
Regenerated Silk Fibroin ◽  
Centrifugal Spinning ◽  
Β Sheet

Centrifugal spinning converts the conformation of silk fibroin from random coil to β-sheet more easily than electrospinning, which results in fiber differences on secondary structures, orientation and thermal properties.

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.

Self-assembly of regenerated silk fibroin from random coil nanostructures to antiparallel β-sheet nanostructures

Biopolymers ◽  
2014 ◽  
Vol 101 (12) ◽  
pp. 1181-1192 ◽  
Author(s):  
Jian Zhong ◽  
Mengjia Ma ◽  
Wenying Li ◽  
Juan Zhou ◽  
Zhiqiang Yan ◽  
...  
Keyword(s):  
Silk Fibroin ◽  
Self Assembly ◽  
Random Coil ◽  
Regenerated Silk Fibroin ◽  
Β Sheet

Property Research of Silk Fibroin Nanofibers by Electrospinning Dissolved in CaCl2-Formid Acid

2015 ◽  
Vol 1120-1121 ◽  
pp. 331-336
Author(s):  
Yan Zhou ◽  
Hui Ying Wu
Keyword(s):  
Mechanical Properties ◽  
Silk Fibroin ◽  
Solvent System ◽  
Dissolution Time ◽  
Ethanol Treatment ◽  
Regenerated Silk Fibroin ◽  
Silk Fibroin Nanofibers ◽  
Different Content ◽  
Β Sheet ◽  
Paper Property

In this paper, property research of silk fibroin nanofibers by electrospinning dissolved in CaCl2-Formid Acid was discussed. The dissolve process, morphology, structure and mechanical properties of fibers were studied. It showed that more dissolution time was needed to dissolve silk with 1% CaCl2. The diameters of silk fibroin nanofibers decreased with the CaCl2 contents increased and the surface of 6%5% fibers was more uniform and smooth. After ethanol treatment, strong peak at 1628cm-1, 1517cm-1 and 1231cm-1 was corresponding to β-sheet. It was important to discover that silk fibroin was weakly destroyed in CaCl2-FA solvent system, and the regenerated silk fibroin nanofibers had better mechanical properties. The stress of 6%5% fibers was nearly 3 times to traditional way. With different content of CaCl2, the stress of 6%5% fibers was nearly 2 times to 6%1% fibers.

scholarly journals Silk inverse opals from template-directed β-sheet transformation of regenerated silk fibroin

Soft Matter ◽  
2007 ◽  
Vol 3 (11) ◽  
pp. 1377 ◽  
Author(s):  
Victoria M. Swinerd ◽  
Andrew M. Collins ◽  
Nicholas J. V. Skaer ◽  
Tom Gheysens ◽  
Stephen Mann
Keyword(s):  
Silk Fibroin ◽  
Inverse Opals ◽  
Regenerated Silk Fibroin ◽  
Β 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.

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