Mussel Inspired Dynamic Cross-Linking of Self-Healing Peptide Nanofiber Network

Authors

  • Hakan Ceylan,

    1. Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey
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  • Mustafa Urel,

    1. Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey
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  • Turan S. Erkal,

    1. Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey
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  • Ayse B. Tekinay,

    1. Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey
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  • Aykutlu Dana,

    Corresponding author
    1. Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey
    • Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey.
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  • Mustafa O. Guler

    Corresponding author
    1. Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey
    • Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey.
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Abstract

A general drawback of supramolecular peptide networks is their weak mechanical properties. In order to overcome a similar challenge, mussels have adapted to a pH-dependent iron complexation strategy for adhesion and curing. This strategy also provides successful stiffening and self-healing properties. The present study is inspired by the mussel curing strategy to establish iron cross-link points in self-assembled peptide networks. The impact of peptide-iron complexation on the morphology and secondary structure of the supramolecular nanofibers is characterized by scanning electron microscopy, circular dichroism and Fourier transform infrared spectroscopy. Mechanical properties of the cross-linked network are probed by small angle oscillatory rheology and nanoindentation by atomic force microscopy. It is shown that iron complexation has no influence on self-assembly and β-sheet-driven elongation of the nanofibers. On the other hand, the organic-inorganic hybrid network of iron cross-linked nanofibers demonstrates strong mechanical properties comparable to that of covalently cross-linked network. Strikingly, iron cross-linking does not inhibit intrinsic reversibility of supramolecular peptide polymers into disassembled building blocks and the self-healing ability upon high shear load. The strategy described here could be extended to improve mechanical properties of a wide range of supramolecular polymer networks.

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