scholarly journals On the Secondary Structure of Silk Fibroin Nanoparticles Obtained Using Ionic Liquids: An Infrared Spectroscopy Study

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1294
Author(s):  
Guzmán Carissimi ◽  
Cesare M. Baronio ◽  
Mercedes G. Montalbán ◽  
Gloria Víllora ◽  
Andreas Barth
Keyword(s):  
Ionic Liquids ◽  
Secondary Structure ◽  
Infrared Spectrum ◽  
Silk Fibroin ◽  
Liquid Solution ◽  
Power Ultrasound ◽  
Sheet Structure ◽  
Silk Fibroin Nanoparticles ◽  
Ionic Liquid Solution ◽  
Β Sheet

Silk fibroin from Bombyx mori caterpillar is an outstanding biocompatible polymer for the production of biomaterials. Its impressive combination of strength, flexibility, and degradability are related to the protein’s secondary structure, which may be altered during the manufacture of the biomaterial. The present study looks at the silk fibroin secondary structure during nanoparticle production using ionic liquids and high-power ultrasound using novel infrared spectroscopic approaches. The infrared spectrum of silk fibroin fibers shows that they are composed of 58% β-sheet, 9% turns, and 33% irregular and/or turn-like structures. When fibroin was dissolved in ionic liquids, its amide I band resembled that of soluble silk and no β-sheet absorption was detected. Silk fibroin nanoparticles regenerated from the ionic liquid solution exhibited an amide I band that resembled that of the silk fibers but had a reduced β-sheet content and a corresponding higher content of turns, suggesting an incomplete turn-to-sheet transition during the regeneration process. Both the analysis of the experimental infrared spectrum and spectrum calculations suggest a particular type of β-sheet structure that was involved in this deficiency, whereas the two other types of β-sheet structure found in silk fibroin fibers were readily formed.

Fabrication of robust silk fibroin film by controlling the content of β-sheet via the synergism of Uv-light and ionic liquids

2019 ◽  
Vol 492 ◽  
pp. 55-65 ◽  
Author(s):  
Congxia Xie ◽  
Wenjing Li ◽  
Qingqing Liang ◽  
Shitao Yu ◽  
Lu Li
Keyword(s):  
Ionic Liquids ◽  
Silk Fibroin ◽  
Uv Light ◽  
Silk Fibroin Film ◽  
Β Sheet

Production of silk fibroin nanoparticles using ionic liquids and high-power ultrasounds

2014 ◽  
pp. n/a-n/a ◽  
Author(s):  
Antonio Abel Lozano-Pérez ◽  
Mercedes García Montalbán ◽  
Salvador David Aznar-Cervantes ◽  
Francesca Cragnolini ◽  
José Luis Cenis ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Silk Fibroin ◽  
High Power ◽  
Silk Fibroin Nanoparticles

scholarly journals Effect of pH on the Conformational Transition of Silk Fibroin in Aqueous Solution Monitored by Thioflavin-T Fluorescence

2021 ◽  
Author(s):  
Ben Jia ◽  
Lan Jia ◽  
Jingxin Zhu
Keyword(s):  
Aqueous Solution ◽  
Secondary Structure ◽  
Silk Fibroin ◽  
Conformational Transition ◽  
Thioflavin T ◽  
Random Coil ◽  
Fluorescence Dye ◽  
Assembly Behavior ◽  
Β Sheet

Abstract In this work, the potential application of the fluorescence dye Thioflavin-T (ThT), which can specifically bind to amyloid, as a powerful tool for monitoring secondary structure transitions of silk fibroin (SF) induced by pH was examined. Results showed that ThT emission intensities substantially increased when pH decreased from 6.8 to 4.8. This increase may be due to conformational transitions from random coil to β-sheet. The morphology and secondary structure of SF were also investigated via TEM, AFM and circular dichroism spectroscopy. The information obtained herein can be utilized not only for the development of convenient and efficient noninvasive method for monitoring the assembly behavior of SF in aqueous solution but also for in vitro fluorescence imaging.

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.

scholarly journals Ionic Liquids and Water: Hydrophobicity vs. Hydrophilicity

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7159
Author(s):  
Rita F. Rodrigues ◽  
Adilson A. Freitas ◽  
José N. Canongia Lopes ◽  
Karina Shimizu
Keyword(s):  
Ionic Liquid ◽  
Hydrogen Bonding ◽  
Ionic Liquids ◽  
Aqueous Media ◽  
Liquid Solution ◽  
Chemical Processes ◽  
Processes And Reactions ◽  
High Hydrogen ◽  
Ionic Liquid Solution ◽  
Dynamics Simulations

Many chemical processes rely extensively on organic solvents posing safety and environmental concerns. For a successful transfer of some of those chemical processes and reactions to aqueous media, agents acting as solubilizers, or phase-modifiers, are of central importance. In the present work, the structure of aqueous solutions of several ionic liquid systems capable of forming multiple solubilizing environments were modeled by molecular dynamics simulations. The effect of small aliphatic chains on solutions of hydrophobic 1-alkyl-3-methylimidazolium bis(trifluoromethyl)sulfonylimide ionic liquids (with alkyl = propyl [C3C1im][NTf2], butyl [C4C1im][NTf2] and isobutyl [iC4C1im][NTf2]) are covered first. Next, we focus on the interactions of sulphonate- and carboxylate-based anions with different hydrogenated and perfluorinated alkyl side chains in solutions of [C2C1im][CnF2n+1SO3], [C2C1im][CnH2n+1SO3], [C2C1im][CF3CO2] and [C2C1im][CH3CO2] (n = 1, 4, 8). The last system considered is an ionic liquid completely miscible with water that combines the cation N-methyl-N,N,N-tris(2-hydroxyethyl)ammonium [N1 2OH 2OH 2OH]+, with high hydrogen-bonding capability, and the hydrophobic anion [NTf2]–. The interplay between short- and long-range interactions, clustering of alkyl and perfluoroalkyl tails, and hydrogen bonding enables a wealth of possibilities in tailoring an ionic liquid solution according to the needs.

scholarly journals The Relationship between Secondary Structure and Biodegradation Behavior of Silk Fibroin Scaffolds

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Yongpei Hu ◽  
Qin Zhang ◽  
Renchuan You ◽  
Lingshuang Wang ◽  
Mingzhong Li
Keyword(s):  
Tissue Engineering ◽  
Secondary Structure ◽  
Silk Fibroin ◽  
Degradation Rate ◽  
Mechanical Performance ◽  
Tissue Growth ◽  
Random Coil ◽  
Regenerated Silk Fibroin ◽  
Sheet Structure ◽  
The Relationship

Silk fibroin has a unique and useful combination of properties, including good biocompatibility and excellent mechanical performance. These features provided early clues to the utility of regenerated silk fibroin as a scaffold/matrix for tissue engineering. The silk fibroin scaffolds used for tissue engineering should degrade at a rate that matches the tissue growth rate. The relationship between secondary structure and biodegradation behavior of silk fibroin scaffolds was investigated in this study. Scaffolds with different secondary structure were prepared by controlling the freezing temperature and by treatment with carbodiimide or ethanol. The quantitative proportions of each secondary structure were obtained by Fourier transform infrared spectroscopy (FTIR), and each sample was then degradedin vitrowith collagenase IA for 18 days. The results show that a high content ofβ-sheet structure leads to a low degradation rate. The random coil region in the silk fibroin material is degraded, whereas the crystal region remains stable and the amount ofβ-sheet structure increases during incubation. The results demonstrate that it is possible to control the degradation rate of a silk fibroin scaffold by controlling the content ofβ-sheet structure.

Packing arrangement of 13C selectively labeled sequence model peptides of Samia cynthia ricini silk fibroin fibers studied by solid-state NMR

2017 ◽  
Vol 19 (20) ◽  
pp. 13379-13386 ◽  
Author(s):  
Tetsuo Asakura ◽  
Kenta Miyazawa ◽  
Yugo Tasei ◽  
Shunsuke Kametani ◽  
Yasumoto Nakazawa ◽  
...  
Keyword(s):  
Solid State ◽  
Silk Fibroin ◽  
Solid State Nmr ◽  
Silk Fibroin Fiber ◽  
Sheet Structure ◽  
Staggered Arrangement ◽  
Packing Arrangement ◽  
Β Sheet ◽  
Model Peptides

Samia cynthia ricini silk fibroin fiber was proposed to take anti-parallel β-sheet structure with staggered arrangement.

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