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Layered Gradient Nonwovens of In Situ Crosslinked Electrospun Collagenous Nanofibers Used as Modular Scaffold Systems for Soft Tissue Regeneration

Authors

  • Marco Angarano,

    1. Freiburg Materials Research Center (FMF) and Institute for Macromolecular Chemistry of the Albert-Ludwigs University Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany
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  • Simon Schulz,

    1. Department of Oral Biotechnology, Dental School, University Hospital Freiburg, Hugstetterstrasse 55, D-79106 Freiburg, Germany
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  • Martin Fabritius,

    1. Freiburg Materials Research Center (FMF) and Institute for Macromolecular Chemistry of the Albert-Ludwigs University Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany
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  • Robert Vogt,

    1. Freiburg Materials Research Center (FMF) and Institute for Macromolecular Chemistry of the Albert-Ludwigs University Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany
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  • Thorsten Steinberg,

    1. Department of Oral Biotechnology, Dental School, University Hospital Freiburg, Hugstetterstrasse 55, D-79106 Freiburg, Germany
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  • Pascal Tomakidi,

    1. Department of Oral Biotechnology, Dental School, University Hospital Freiburg, Hugstetterstrasse 55, D-79106 Freiburg, Germany
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  • Christian Friedrich,

    1. Freiburg Materials Research Center (FMF) and Institute for Macromolecular Chemistry of the Albert-Ludwigs University Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany
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  • Rolf Mülhaupt

    Corresponding author
    1. Freiburg Materials Research Center (FMF) and Institute for Macromolecular Chemistry of the Albert-Ludwigs University Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany
    • Freiburg Materials Research Center (FMF) and Institute for Macromolecular Chemistry of the Albert-Ludwigs University Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany.
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Abstract

In a versatile modular scaffold system, gradient nonwovens of in situ crosslinked gelatin nanofibers (CGN), fabricated by reactive electrospinning, are laminated with perforated layers and nonwovens of thermoplastic non-crosslinked biodegradable polyesters. The addition of glyoxal to a gelatin solution in a non-toxic solvent mixture consisting of acetic acid, ethyl acetate, and water (5:3:2 w/w/w) enables the in situ crosslinking of gelatin nanofibers during electrospinning. The use of this fluorine-free crosslinking system eliminates the need of post-treatment crosslinking and purification steps typical for conventional CGN scaffolds. The slowly progressing crosslinking of the dissolved gelatin in the presence of glyoxal increases the viscosity of the gelatin solution during electrospinning so that the average diameter of the crosslinked gelatin nanofibers gradually increases from 90 to 680 nm. During the subsequent lamination process, alternating layers of CGN and polycaprolactone (PCL) nonwovens, produced by 3D microextrusion of micrometer-sized PCL fibers, are bonded together upon heating above the PCL melting temperature. In contrast to the water-soluble gelatin nanofibers and the comparatively weak CGN, the CGN/PCL/CGN layered biocomposites are water-resistant and very robust. In such modular scaffold systems, strength, biodegradation rate, and biological functions can be controlled by varying the type, composition, fiber diameter, porosity, number, and sequence of the individual layers. The CGN/PCL multilayer biocomposites can be cut into any desired scaffold shape and attached to tissue by surgical sutures in order to suit the needs of individual patients.

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