Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly
AbstractThe fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs) and recombinant spider silk protein fused to a cellulose binding domain (CBD) is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhibit improved thermal and structural characteristics in comparison to control recombinant spider silk sponges. The glass transition temperature (Tg) of the silk-CBD sponge was higher than the control silk sponge and similar to native dragline spider silk fibers. Gel filtration analysis, dynamic light scattering (DLS), small angle X-ray scattering (SAXS) and cryo-transmission electron microscopy (TEM) indicated that silk-CBD, but not the recombinant silk control, formed a nematic liquid crystalline phase similar to that observed in native spider silk during the silk spinning process. Silk-CBD microfibrils spontaneously formed in solution upon ultrasonication. We suggest a model for silk-CBD assembly that implicates CBD in the central role of driving the dimerization of spider silk monomers, a process essential to the molecular assembly of spider-silk nanofibers and silk-CNC composites. View Full-Text
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Meirovitch, S.; Shtein, Z.; Ben-Shalom, T.; Lapidot, S.; Tamburu, C.; Hu, X.; Kluge, J.A.; Raviv, U.; Kaplan, D.L.; Shoseyov, O. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly. Int. J. Mol. Sci. 2016, 17, 1573.
Meirovitch S, Shtein Z, Ben-Shalom T, Lapidot S, Tamburu C, Hu X, Kluge JA, Raviv U, Kaplan DL, Shoseyov O. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly. International Journal of Molecular Sciences. 2016; 17(9):1573.Chicago/Turabian Style
Meirovitch, Sigal; Shtein, Zvi; Ben-Shalom, Tal; Lapidot, Shaul; Tamburu, Carmen; Hu, Xiao; Kluge, Jonathan A.; Raviv, Uri; Kaplan, David L.; Shoseyov, Oded. 2016. "Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly." Int. J. Mol. Sci. 17, no. 9: 1573.
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