40 research outputs found
Diffraction from the beta-sheet crystallites in spider silk
We analyze the wide angle x-ray scattering from oriented spider silk fibers
in terms of a quantitative scattering model, including both structural and
statistical parameters of the -sheet crystallites of spider silk in the
amorphous matrix. The model is based on kinematic scattering theory and allows
for rather general correlations of the positional and orientational degrees of
freedom, including the crystallite's size, composition and dimension of the
unit cell. The model is evaluated numerically and compared to experimental
scattering intensities allowing us to extract the geometric and statistical
parameters. We show explicitly that for the experimentally found mosaicity
(width of the orientational distribution) inter-crystallite effects are
negligible and the data can be analyzed in terms of single crystallite
scattering, as is usually assumed in the literature.Comment: 15 pages, 14 figures, on average 0.93 figures per pag
Composition and Hierarchical Organisation of a Spider Silk
Albeit silks are fairly well understood on a molecular level, their hierarchical organisation and the full complexity of constituents in the spun fibre remain poorly defined. Here we link morphological defined structural elements in dragline silk of Nephila clavipes to their biochemical composition and physicochemical properties. Five layers of different make-ups could be distinguished. Of these only the two core layers contained the known silk proteins, but all can vitally contribute to the mechanical performance or properties of the silk fibre. Understanding the composite nature of silk and its supra-molecular organisation will open avenues in the production of high performance fibres based on artificially spun silk material
Interactions between Spider Silk and Cells – NIH/3T3 Fibroblasts Seeded on Miniature Weaving Frames
Native spider silk does not require any modification to its application as a biomaterial that can rival any artificial material in terms of cell growth promoting properties. We could show adhesion mechanics on intracellular level. Additionally, proliferation kinetics were higher than in enzymatically digested controls, indicating that spider silk does not require modification. Recent findings concerning reduction of cell proliferation after exposure could not be met. As biotechnological production of the hierarchical composition of native spider silk fibres is still a challenge, our study has a pioneer role in researching cellular mechanics on native spider silk fibres
Wound dressings for a proteolytic-rich environment
Wound dressings have experienced continuous and significant changes over the years based on the knowledge of the biochemical events associated with chronic wounds. The development goes from natural
materials used to just cover and conceal the wound to interactive materials that can facilitate the healing process, addressing specific issues in non-healing wounds. These
new types of dressings often relate with the proteolytic wound environment and the bacteria load to enhance the healing. Recently, the wound dressing research is focusing on the replacement of synthetic polymers by natural protein materials to delivery bioactive agents to the wounds. This
article provides an overview on the novel protein-based wound dressings such as silk fibroin keratin and elastin.
The improved properties of these dressings, like the release of antibiotics and growth factors, are discussed. The different types of wounds and the effective parameters of
healing process will be reviewed