3.4 New protein cross-linkers for polysaccharide hydrogel formation

A hydrogel is a solid material made of a cross-linked network of hydrated polymer chains. Many hydrogels contain at least 90% water. Hydrogels are extremely useful and versatile materials, as they are strong, flexible, highly absorbent, and adaptable to different applications. Unfortunately, many medical and pharmaceutical-grade hydrogels are still produced using polymers that derive from non-renewable fossil resources. A more sustainable approach is to use biopolymers such as polysaccharides instead, but even these tend to require chemical modification for a hydrogel to form, and organic solvents are commonly used in preparation. We have uncovered a new chemical-free approach to hydrogel formation that makes use of a carbohydrate-binding protein sourced from beneficial soil bacteria. By characterising this protein in depth from a biochemical and structural perspective, we now understand the mechanism of gel formation. And by exploring the polymer chemistry interactions involved in polysaccharide cross-linking and gel formation, we are able to tune the viscosity and rheology of the biomaterial, which opens up many potential avenues for application. Our first proof-of-concept demonstrator uses a β-glucan polysaccharide and we hope to expand to other wood-derived biopolymers as we continue to characterise more proteins in our cross-linking family. Starting in 2022, innovation deriving from the discovery of this gel will be commercialised by the new start-up company GlycoLink AB, recently founded by KTH researchers.