From plant proteins to botanical biomaterials
09 Nov 2026 - Rupo Mapanga
Researchers from the University of Leeds came to ISIS to investigate how an abundant plant protein can be transformed into a sustainable hydrogel with tuneable mechanical and water-absorbing properties for applications in water harvesting and filtration.
Biomaterials derived from renewable resources could provide more sustainable alternatives to materials based on fossil-fuel feedstocks. Plant-derived polymers such as polysaccharides and proteins are attractive because they are abundant and renewable. Proteins offer an additional advantage: their three-dimensional structures can provide intrinsic functionality, making them promising building blocks for materials whose properties can be tailored for different applications.
The challenge is to identify protein sources that are not only functional, but sufficiently abundant and inexpensive to support large-scale applications. Wheat gluten fits this requirement well and is cheap, widely available and produced as a by-product of industries including wheat starch extraction, providing an attractive starting material for a circular approach to biomaterial production.
However, commercial wheat gluten has very poor solubility in water. The Leeds team therefore used controlled hydrolysis to break up the insoluble gluten network and produce a soluble protein extract. They then used light-activated chemical crosslinking to join the protein molecules together into a self-supporting hydrogel. Since the crosslinking is triggered by light, the researchers could control when gel formation begins. By changing the concentration of gluten in the material, the team produced highly elastic hydrogels with storage moduli ranging from approximately 0.2 to 3.5 kPa. This demonstrated that a relatively simple processing route can transform commercial wheat gluten into mechanically robust materials whose rigidity can be tuned through their formulation.
But understanding why these materials behave as they do requires looking inside the hydrogel across much smaller length scales. The researchers therefore used small-angle neutron scattering (SANS) on ZOOM at the ISIS Neutron and Muon Source to investigate the nanoscale and larger mesoscale organisation of the gluten proteins. The measurements revealed dense, fractal-like assemblies of crosslinked gluten proteins forming an interconnected network. Importantly, the underlying geometry of these assemblies remained similar across the range of gluten concentrations investigated, even as the bulk mechanical rigidity changed. Cryogenic scanning electron microscopy at Leeds provided a complementary view of the material, revealing a heterogeneous network of protein-rich clusters separated by water-filled pores. Together with the SANS and mechanical measurements, these results point towards a hierarchical material in which the connections between protein assemblies play an important role in determining the macroscopic properties of the hydrogel.
The team also investigated the material’s ability to absorb water. Water absorption opens up the possibility of future sustainability applications, including materials for water retention. Gluten hydrogels reached their maximum swelling after approximately three hours, with swelling capacities that could be varied from approximately 100% to 200% by changing the concentration of the chemical crosslinker. Interestingly, maximum swelling did not simply track the hydrogel’s bulk stiffness, suggesting that the mesoscale pore network also plays an important role in determining how much water the material can hold. Commercial superabsorbent gels can absorb substantially more water, but commonly use sodium polyacrylate, a petrochemical-derived polymer. The gluten hydrogels represent an early step towards exploring renewable protein-based alternatives.
We have shown that an abundant plant-derived material can be transformed, using relatively straightforward processing, into a robust hydrogel whose mechanical and water-absorbing properties can be tuned.
Professor Lorna Dougan from the University of Leeds
“We have shown that an abundant plant-derived material can be transformed, using relatively straightforward processing, into a robust hydrogel whose mechanical and water-absorbing properties can be tuned,” says Professor Lorna Dougan from the University of Leeds. “By combining neutron scattering with mechanical measurements and microscopy, we can begin to understand how the organisation of the gluten proteins across different length scales gives rise to these macroscopic properties.”
This new study establishes wheat gluten as a promising building block for sustainable protein-based hydrogels. Further mapping how processing conditions control their hierarchical structure, mechanics and water absorption could enable these renewable materials to be designed for specific applications.
The project was supported by a grant from the Engineering and Physical Sciences Research Council (EPSRC) (EP/ P02288X/1) to L. Dougan, and the Engineering and Physical Sciences Research Council (EPSRC) Centre for Doctoral Training (CDT) in Molecules to Product grant ref. EP/S022479/1.
You can read the manuscript here:
Botanical biomaterials: From wheat gluten to sustainable hydrogels – ScienceDirect
