Researchers from the Pritzker School of Engineering (UChicago PME) and the Department of Chemistry at the University of Chicago have recently achieved a breakthrough by successfully converting malva nut, commonly used in herbal tea, into a hydrogel suitable for various biomedical applications. This research was published today in the Matter journal.

This study is not based on the health benefits of malva nut (known as pangdahai in China) as described in folklore but focuses on its unique swelling ability in water. The first author, Sun Changxu, a Ph.D. candidate at UChicago PME, stated, "You've never seen a fruit from a tree grow to such a large volume. Once soaked in water, the malva nut swells about eight times in volume and twenty times in weight, transforming into a gel-like substance, much like jelly."

However, for most people, this jelly-like substance is usually discarded after drinking the herbal tea. But Sun Changxu and his advisor, Professor Tian Boxiang from the University of Chicago's Department of Chemistry, saw great potential in it. Professor Tian praised, "This is an outstanding discovery by an exceptional student. Changxu saw a world of sustainable biomedical applications through studying herbal tea, waiting for us to create."

Hydrogels are a viscous water-based substance popular due to their various applications in healthcare. They are as soft and hydrophilic as human tissues and can be used for wound care, anti-infection, and healing promotion, as well as drug delivery systems, implantable bioelectronics (such as pacemakers), tissue repair, ECG readings, and more.

To convert the Malva nut into a medical device, the research team conducted a series of meticulous processes. They first crushed the nuts, then extracted the soft, swollen polysaccharide colloids while removing the hard lignin structure. Next, they freeze-dried the colloidal solution to remove all moisture, forming a dry scaffold of pure malva nut polysaccharides. Professor Sun explained, "If we rehydrate these scaffolds, they will turn into a gel."

The research team subsequently conducted extensive testing on the malva nut hydrogel, exploring its potential applications in various medical uses, ranging from wound care to biological monitoring. Sun Changxu said, "We found that it exhibited superior performance and quality compared to commercial ECG patches. We also applied it to the surface of tissues in vivo, demonstrating excellent biosignal recording capabilities."

Sun Changxu hopes that this natural hydrogel can provide a new, potent yet low-cost medical resource globally, especially for Southeast Asian countries where malva trees are abundant. He said, "These countries are low-income, and their healthcare systems are always constrained by resource scarcity. We have local native materials here that can be used to create valuable healthcare solutions while providing some economic stability for these impoverished areas."

This research not only showcases the tremendous potential of malva nut in the biomedical field but also provides new ideas and methods for developing sustainable and low-cost medical resources.