| Rheology and dynamic light scattering of silk fibroin solution extracted from the middle division of Bombyx mori silkworm. | |
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MedLine Citation:
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PMID: 12425655 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Dynamic light scattering (DLS) and rheological measurements were performed on aqueous silk fibroin solutions extracted from the middle division of Bombyx mori silkworm over a wide range of polymer concentration C from 0.08 to 27.5 wt %. DLS results obtained in the dilute region of C less than 1 wt % are consistent with a model that an elementary unit is a large protein complex consisting of silk fibroin and P25 with a 6:1 molar ratio. Rheological measurements in the dilute C region reveal that those units (or clusters) with the hydrodynamic radius of about 100 nm form a network extending over the whole sample volume with small pseudoplateau modulus mainly by ionic bonding between COO(-) ions of the fibroin molecules and divalent metallic ions such as Ca(2+) or Mg(2+) ions present in the sample and also that, after a yield stress is reached, steady plastic flow is induced with viscosity much lower than the zero-shear viscosity estimated from creep and creep recovery measurements by 4-6 orders of magnitude. Angular frequency omega dependencies of the storage and the loss shear moduli, G'(omega) and G' '(omega), measured in the linear viscoelastic region, indicate that all solutions possess the pseudoplateau modulus in the low omega region and samples become highly viscoleastic for C greater, similar 4.2 wt %. Above C = 11.2 wt % another plateau appears at the high omega end accompanied by a distinct maximum of G' ' in the intermediate omega region. The relaxation motion with tau = 0.5 s corresponding to the maximum of G' ' is one of characteristic properties of the fibroin solutions in the high C region. Thermorheological behaviors of the solution with C = 27.5 wt % show that the network structure formed in the MM part of the silk gland is susceptible to temperature and a more stable homogeneous network is realized by raising the temperature up to T = 65 degrees C. |
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Authors:
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Akie Ochi; Khandker S Hossain; Jun Magoshi; Norio Nemoto |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Biomacromolecules Volume: 3 ISSN: 1525-7797 ISO Abbreviation: Biomacromolecules Publication Date: 2002 Nov-Dec |
Date Detail:
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Created Date: 2002-11-11 Completed Date: 2003-08-13 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 100892849 Medline TA: Biomacromolecules Country: United States |
Other Details:
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Languages: eng Pagination: 1187-96 Citation Subset: IM |
Affiliation:
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Department of Molecular and Material Sciences, IGSES, Kyushu University, Hakozaki, Fukuoka 812-8581, Japan. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Bombyx Calcium Fibroins / chemistry* Insect Proteins / chemistry* Rheology* Scattering, Radiation Silk Solutions |
| Chemical | |
Reg. No./Substance:
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0/Insect Proteins; 0/Silk; 0/Solutions; 7440-70-2/Calcium; 9007-76-5/Fibroins |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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