FLOW paper published in ACS Nano

The paper ‘Ultrastrong and Bioactive Nanostructured Bio-Based Composites’ by Nitesh Mittal, Ronnie Jansson, Mona Widhe, Tobias Benselfelt, Karl Håkansson, Fredrik Lundell, My Hedhammar and Daniel Söderberg has been published in ACS Nano, the second highest ranked journal in the area of Nanotechnology and top ten in the area of Material Science. The research is a collaboration between scientists from Linné FLOW Centre, Wallenberg Wood Science Center, the School of Biotechnology at KTH and RISE (Research Institutes of Sweden).

 

Abstract: Nature’s design of functional materials relies on smart combinations of simple components to achieve desired properties. Silk and cellulose are two clever examples from nature – spider silk being tough due to high extensibility, whereas cellulose possess unparalleled strength and stiffness among natural materials. Unfortunately, silk proteins cannot be obtained in large quantities from spiders and recombinant production processes are so far rather expensive. We have therefore combined small amounts of functionalized recombinant spider silk proteins (RSP) with the most abundant structural component on earth (cellulose nanofibrils (CNF)) to fabricate isotropic as well as anisotropic hierarchical structures. Our approach for the fabrication of bio-based anisotropic fibers results in previously unreached but highly desirable mechanical performance with a stiffness ~55 GPa, strength at break ~1015 MPa, and toughness ~55 MJ m-3. We also show that addition of small amounts of silk fusion proteins to CNF result in materials with advanced bio-functionalities, which cannot be anticipated for the wood-based CNF alone. These findings suggest that bio-based materials provide abundant opportunities to design composites with high strength and functionalities and bring down our dependence on fossil-based resources.