The world of gels and hydrogels may seem a little mundane to the general public, but new research is showing that their potential is both vast and exciting. Assistant Professor Geonzon, using a new toughening technique for hydrogels called “strain-induced ordering,” is stretching the boundaries of what is possible with bio-based gels and bio-hydrogels, from bioengineering and regenerative medicine to agriculture and elder care. 

Controlling the mechanical properties of natural-based polymers 

My research centers on developing soft materials from natural polymers. In general, they are materials that exhibit both solid-like and liquid-like properties. The most common of these are gel-like materials—gels and hydrogels—which consist of a three-dimensional network that can hold large amounts of liquid. In the case of hydrogels, the liquid is water. 

There are already synthetic gels with a wide range of useful properties. These can be tougher than natural ones, but they have limitations due to lack of biocompatibility and biodegradability. The problem with natural polymers is that their mechanical properties, such as stiffness and toughness, are difficult to tune over a wide range, because they are inherently weak and soft. Tough and soft natural polymers would find numerous applications as a replacement for plastics in tissue engineering, agriculture, food science and many other fields. Therefore, my main research seeks to bridge this gap and address the limitations of natural-based materials by controlling their structure and improving their mechanical properties, especially focusing on natural polymer hydrogels (bio-based hydrogels). 

A new strategy to increase the strength of natural polymers 

Natural polymers have an inherent conformation in nature. For example, one of the most common natural polymers is gelatin, which is a polymer from collagen, a component of bodily tissues. On dissolving in water, gelatin transforms into hydrogel. 

Both collagen and gelatin in collagen naturally form a triple helical structure and organize it to form the tissues. When the gelatin is extracted from collagen, it can be in linear form, like a free random conformation. When specific conditions are met, like temperature, concentration and so on, this collagen naturally transforms to form the triple helical structure. But because of this intrinsic conformation, it’s very difficult to control the network structure of natural polymers. Similarly, naturalbased polymers such as polysaccharides like carrageenan undergo comparable conformational transformations that lead to a sol–gel transition. This phenomenon is commonly observed in everyday settings, such as during the preparation of dessert jelly in the kitchen (Fig), liquid when heated yet solid when cooled. 

Fig. Supplementary Cover of Macromolecules. This art depicts the network structure of mixed κ- and ι-carrageenan chains that control the macroscopic viscoelasticity and texture of the carrageenan-based gels.  
Geonzon et al. Macromolecules 2023, 56, 21, 8676–8687, https://pubs.acs.org/doi/10.1021/acs.macromol.3c00747.  https://pubs.acs.org/toc/mamobx/56/21 

I recently, together with my previous supervisor at the Institute for Solid State Physics, The University of Tokyo we utilized the new toughening strategy for synthetic hydrogels called “strain-induced crystallization or ordering,” to develop strong natural-based hydrogels. Many synthetic polymers become weaker and more prone to breakage when stretched. But with strain-induced crystallization or ordering, the synthetic gels when stretched, become stronger and tougher. Until now, no one believed this strategy could be used with natural hydrogels; however, we found that this strain-induced mechanism can be used to enhance the mechanical properties of natural hydrogels, including those made from polysaccharides.   

To achieve the strain-induced ordering phenomenon, natural hydrogels are reinforced by using cross-linkers—such as specific chemical agents and/or metal ions—to tightly bond their molecular chains, preventing them from breaking even under significant tension. When stretched, these molecular bundles align precisely in the direction of the force, rendering the hydrogel remarkably strong and tough. 

Potential applications in a broad range of fields 

The applications could be endless. For example, gel-based foods can be anything from soft and easy-to-eat like pudding to firm and tough like beef jerky. One focus of my research is with elder care. A serious problem with the elderly is that they have trouble swallowing as the muscles used to swallow become weak. So a highly controlled texture for food applications could make it easier and safer to swallow food.  

Their intrinsic property to form three-dimensional network structures makes them promising for tissue engineering applications as well, because you can make both soft muscle tissues and tough ones like tendon and cartilage. Most tough gels are made from synthetic polymers, but many synthetic gels have limitations in biocompatibility and biodegradability. Controlling the mechanical properties of hydrogels from natural polymers could be a good approach. Accordingly, I have started to make tough and strong hydrogels from polysaccharides as well as collagens and gelatins (photo).

Photograph of stiff and tough biobased hydrogel made from carrageenan. (Photo by Lester Canque GEONZON )  

And currently, because I am in the agrobioresource department of this university, I am focusing more on agricultural applications. Plastics can be very harmful for the environment—over time, they degrade, become microplastics and cause problems in the environment. Materials developed from natural-based gels could be used to replace those plastics.  

Multiple fruitful topics of future research 

As for my future research, I see several routes it could take. For example, I am focusing on using hydrogels as a soil conditioner. Because hydrogels can hold a lot of water, they can be used to keep water in soil, like a reservoir, and control water release during dry seasons. This could save water, as well as help prevent erosion.  

Japanese farmers use a kind of black plastic mulch that degrades over time, producing microplastics, which are very persistent in the soil. I hope to develop a material from polysaccharides and hydrogels to mimic the functional properties of this plastic mulch, such as water retention and soil coverage, while remaining biodegradable.   

The problem of microplastics has been around for many years. There are already strategies to solve this issue, but my strong point is that I have natural materials and strategies to control the structure of the natural materials. Integrating all these can be addressed in my research, and I believe this can be used to develop bioplastics from natural polymers. This will be the focus of my research going forward.  

(Date of interview: February 12, 2026)