Abstract:
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Polylaminin (polyLM) is a non-covalent acid-induced nano- and micro-structured polymer of the protein laminin displaying
distinguished biological properties. Polylaminin stimulates neuritogenesis beyond the levels achieved ...[+]
Polylaminin (polyLM) is a non-covalent acid-induced nano- and micro-structured polymer of the protein laminin displaying
distinguished biological properties. Polylaminin stimulates neuritogenesis beyond the levels achieved by ordinary laminin
and has been shown to promote axonal regeneration in animal models of spinal cord injury. Here we used confocal
fluorescence microscopy (CFM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) to characterize its
three-dimensional structure. Renderization of confocal optical slices of immunostained polyLM revealed the aspect of a
loose flocculated meshwork, which was homogeneously stained by the antibody. On the other hand, an ordinary matrix
obtained upon adsorption of laminin in neutral pH (LM) was constituted of bulky protein aggregates whose interior was not
accessible to the same anti-laminin antibody. SEM and AFM analyses revealed that the seed unit of polyLM was a flat
polygon formed in solution whereas the seed structure of LM was highly heterogeneous, intercalating rod-like, spherical
and thin spread lamellar deposits. As polyLM was visualized at progressively increasing magnifications, we observed that
the morphology of the polymer was alike independently of the magnification used for the observation. A search for the
Hausdorff dimension in images of the two matrices showed that polyLM, but not LM, presented fractal dimensions of 1.55,
1.62 and 1.70 after 1, 8 and 12 hours of adsorption, respectively. Data in the present work suggest that the intrinsic fractal
nature of polymerized laminin can be the structural basis for the fractal-like organization of basement membranes in the
neurogenic niches of the central nervous system.
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Thanks:
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This work was supported by a grant from the Brazilian National Research Council (CNPq; 476772/2008-7) to TCS. MSS acknowledges support from the European Research Council through ERC - 306990. The funders had no role in ...[+]
This work was supported by a grant from the Brazilian National Research Council (CNPq; 476772/2008-7) to TCS. MSS acknowledges support from the European Research Council through ERC - 306990. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
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