Microstructural change of degummed Bombyx mori silk: An in situ stretching wide-angle X-ray-scattering study

Liang, Ku; Gong, Yu; Fu, Jianlong; Shen, Yan; Tan, Yuanyuan; Du, Rongguang; Xing, Xueqing; Mo, Guang; Chen, Zhongjun; Cai, Quan; Sun, Dongbai; Wu, Zhonghua

doi:10.1016/j.ijbiomac.2013.02.018

Cited by 16 publications

(13 citation statements)

References 21 publications

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“…This resulted in crystallite dimensions of 3, 4, and 5 nm in the a, b , and c axes, respectively. 25 Azimuthal broadening of the crystalline reflections is indicative of variance in alignment of the crystalline fraction with respect to the fiber axis. Hermans orientation factor of the crystalline fraction, f c , was calculated to be 0.93, from the FWHM of radial integration at 4.3 Å −1 where f c = (3(cos 2 Φ )−1)/2 and Φ is the angle between the c axis of the nanocrystallite and the fiber axis.…”

Section: Resultsmentioning

confidence: 99%

“…Studies on spider dragline silk fibers show that the crystallinity content ranges from about 30% ( Nephila clavipes ) to 40% ( Latrodectus hesperus ), 23,24 while fibers from the domesticated silkworm are typically higher, in the range of 40–60% crystallinity. 25,26 The crystalline fractions arise mainly from repeated sequences, thus the primary protein sequence for webspinner silks should yield predictive power; protein secondary structure within spider dragline silk fibers has been shown to correlate quantitatively with silk primary protein sequences. 24,27 With the exception of short C-terminal domains, the protein sequences of many embiopteran silks are virtually entirely composed of repetitive motifs, which likely adopt a β-sheet structure.…”

Section: Introductionmentioning

confidence: 99%

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Structural characterization of nanofiber silk produced by embiopterans (webspinners)

et al. 2014

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Embiopterans produce silken galleries and sheets using exceptionally fine silk fibers in which they live and breed. In this study, we use electron microscopy (EM), Fourier-transform infrared (FT-IR) spectroscopy, wide angle X-ray diffraction (WAXD) and solid-state nuclear magnetic resonance (ssNMR) techniques to elucidate the molecular level protein structure of webspinner (embiid) silks. Silks from two species Antipaluria urichi and Aposthonia ceylonica are studied in this work. Electron microscopy images show that the fibers are about 90–100 nm in diameter, making webspinner silks among the finest of all known animal silks. Structural studies reveal that the silk protein core is dominated by β-sheet structures, and that the protein core is coated with a hydrophobic alkane-rich surface coating. FTIR spectra of native embiid silk shows characteristic alkane CH2 stretchings near 2800–2900 cm−1, which decrease approximately 50% after washing the silk with 2 : 1 CHCl3 : MeOH. Furthermore, 13C ssNMR data shows a significant CH2 resonance that is strongly affected by the presence of water, supporting the idea that the silk fibers are coated with a hydrocarbon-rich layer. Such a layer is likely used to protect the colonies from rain. FTIR data also suggests that embiid silks are dominated by β-sheet secondary structures similar to spider and silkworm silk fibers. NMR data confirms the presence of β-sheet nanostructures dominated by serine-rich repetitive regions. A deconvolution of the serine Cβ NMR resonance reveals that approximately 70% of all seryl residues exist in a β-sheet structure. This is consistent with WAXD results that suggest webspinner silks are 70% crystalline, which is the highest crystalline fraction reported for any animal silks. The work presented here provides a molecular level structural picture of silk fibers produced by webspinners.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Structural characterization of nanofiber silk produced by embiopterans (webspinners)

et al. 2014

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“…The intra and intermolecular hydrogen bond network provide strength and tensile strength to the biopolymer, while amorphous regions provide flexibility and elasticity [29]. In the literature, there is great variability in the sizes reported for these crystals [30][31][32][33]. To illustrate the size of these, reference can be made to X-ray diffraction measurements and low voltage transmission electron microscopy performed by Drummy et al [30].…”

Section: Figurementioning

confidence: 99%

Silk Fibroin Nanoparticles: Synthesis and Applications as Drug Nanocarriers

Carissimi¹,

Montalbán²,

Fuster³

et al. 2022

21st Century Nanostructured Materials - Physics, Chemistry, Classification, and Emerging Applications in Industry, Biomedicine,

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The use of nanoparticles in biomedical fields is a very promising scientific area and has aroused the interest of researchers in the search for new biodegradable, biocompatible and non-toxic materials. This chapter is based on the features of the biopolymer silk fibroin and its applications in nanomedicine. Silk fibroin, obtained from the Bombyx mori silkworm, is a natural polymeric biomaterial whose main features are its amphiphilic chemistry, biocompatibility, biodegradability, excellent mechanical properties in various material formats, and processing flexibility. All of these properties make silk fibroin a useful candidate to act as nanocarrier. In this chapter, the structure of silk fibroin, its biocompatibility and degradability are reviewed. In addition, an intensive review on the silk fibroin nanoparticle synthesis methods is also presented. Finally, the application of the silk fibroin nanoparticles for drug delivery acting as nanocarriers is detailed.

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“…Natural biopolymers are similar to both biological macromolecules present and metabolized in the biological environment 1 and the extracellular matrix, including collagen, gelatin, alginate, chitosan, hyaluronic acid, and silk fibroin (SF), which have shown high applicability for wound healing. Among such biopolymers, SF is a fibrous protein extracted from silkworm cocoons of Bombyx mori species and whose molecular structure is composed of hydrophilic and hydrophobic groups represented by α‐helix and β‐sheet secondary structures, respectively 2 . Those structures enable the obtaining of materials of specific properties (amorphous or crystalline characteristics), since, depending on the type of chemical and/or physical stimulus, the α‐helix structure can be converted into a β‐sheet one (crystalline domains or the so‐called ordered domains).…”

Section: Introductionmentioning

confidence: 99%

“…Several organic solvents are used for the obtaining of a stable solution of SF, although formic acid has excelled in the production of fibroin films and fibers 1–4 . According to Um et al, 20 the solubilization of fibroin in formic acid leads to a transparent solution that neither aggregates, nor precipitates after a long storage period.…”

Section: Introductionmentioning

confidence: 99%

Large‐area thin films of silk fibroin prepared by two methods with formic acid as solvent and glycerol as plasticizer

Santos

Yoshioka

Branciforti

2021

J of Applied Polymer Sci

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This article reports on an evaluation of the physical, chemical, thermal, morphological, and thermomechanical behavior of silk fibroin (SF) films conducted by a casting process with formic acid as solvent. Thin films of SF with and without glycerol were produced by two different methods, namely M1, from degummed SF, and M2, after degumming, dissolution, dialysis, centrifuge, and freeze‐drying of SF. According to the results, those fabricated by M1 are thinner and the addition of glycerol increased their thickness. All films showed high‐surface area of approximately 1033 cm2, good transparency, flexibility, absence of bubbles, hydrophilic characteristics, and high‐thermal stability. They displayed a predominantly crystalline structure, no heat‐induced crystallization, and spontaneous formation of β‐sheet, favored by a chemical treatment with ethanol and the plasticization with glycerol. Their morphology was dependent on the production method adopted, and the nanofibril structure of SF was kept in the films obtained by M1. The films proved viable for the production of scaffolds for tissue engineering due to their adequate chemical, physical, and thermomechanical properties for this purpose. The preparation methods adopted enabled the regulation of both the structure and the material properties of SF films, and generated films of large dimensions and able for use in the treatment of patients with extensive burns on the body.

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Microstructural change of degummed Bombyx mori silk: An in situ stretching wide-angle X-ray-scattering study

Cited by 16 publications

References 21 publications

Structural characterization of nanofiber silk produced by embiopterans (webspinners)

Structural characterization of nanofiber silk produced by embiopterans (webspinners)

Silk Fibroin Nanoparticles: Synthesis and Applications as Drug Nanocarriers

Large‐area thin films of silk fibroin prepared by two methods with formic acid as solvent and glycerol as plasticizer

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