Combination of wood fibre, spider silk could pose as rival to plastic

 It's a no-brainer that humans have generated tonnes of plastic and are now looking for a better alternative to it. Well, researchers at the Aalto University and VTT Technical Research Centre of Finland have succeeded in discovering a strong and extensible possible substitute for plastic.

They created a truly new bio-based material by gluing together wood cellulose fibres and the silk protein found in spider web threads. The result is a very firm and resilient material which could be used in the future as a possible replacement for plastic, as part of bio-based composites and in medical applications, surgical fibres, textile industry and packaging.

Nature offers great ingredients for developing new materials, such as firm and easily available cellulose and tough and flexible silk used in this research. The advantage with both of these materials is that, unlike plastic, they are biodegradable and do not damage nature the same way micro-plastic do, said lead researcher Prof Markus Linder at the Aalto University.

"We used birch tree pulp, broke it down to cellulose nanofibrils and aligned them into a stiff scaffold. At the same time, we infiltrated the cellulosic network with a soft and energy dissipating spider silk adhesive matrix," explained research scientist Pezhman Mohammadi from VTT.

Silk is a natural protein which is excreted by animals like silkworms and also found in spider web threads. The spider web silk used by Aalto University researchers, however, is not actually taken from spider webs but is instead produced by the researchers using bacteria with synthetic DNA.

"Because we know the structure of the DNA, we can copy it and use this to manufacture silk protein molecules which are chemically similar to those found in spider web threads. The DNA has all this information contained in it," Linder explained.

"Our work illustrates the new and versatile possibilities of protein engineering. In the future, we could manufacture similar composites with slightly different building blocks and achieve a different set of characteristics for other applications," said Pezhman.