New material adheres to skin and rough surfaces while allowing controlled degradation, with potential applications in wound dressings, drug delivery patches and functional cosmetics

KAIST Professor Lee Haeshin (right) and researcher Yang Han-yeol examine the newly developed hydrogel material. [KAIST]
KAIST Professor Lee Haeshin (right) and researcher Yang Han-yeol examine the newly developed hydrogel material. [KAIST]

A new hydrogel material with more than five times the adhesive strength of conventional alternatives has been developed, opening potential applications in functional cosmetics, medical wound dressings and drug delivery patches.

KAIST announced Monday that a research team led by Lee Haeshin, a chair professor in the Department of Chemistry, developed a new material design strategy using tannic acid — a type of polyphenol and natural antioxidant found abundantly in tea and fruit — to enhance the mechanical strength and adhesiveness of seaweed-derived hydrogels while enabling control over their degradation rate.

Hydrogels are water-rich gel materials used in products such as contact lenses, acne patches, sheet masks and wound care dressings. They adhere closely to skin while retaining drugs or active ingredients, making them widely used across biotech and healthcare fields — including as drug delivery systems, wound coverings, tissue engineering scaffolds and cosmetics ingredients. Conventional hydrogels made from kappa-carrageenan, however, have been difficult to strengthen, make more adhesive or tune to a desired degradation rate.

To address those limitations, Lee turned his attention to tannic acid, a natural polyphenol found in tea and fruit.

Polyphenols are natural compounds that plants produce to protect themselves from external stressors such as ultraviolet radiation and pests, and they can bond with multiple substances at the same time. Tannic acid in particular was expected to be effective because its multiple binding sites allow it to interact strongly with the sulfate groups in kappa-carrageenan, linking the molecules together.

A schematic diagram illustrating potential applications of the hydrogel material (AI-generated image). [KAIST]
A schematic diagram illustrating potential applications of the hydrogel material (AI-generated image). [KAIST]

The research confirmed that sulfate groups — previously considered an obstacle to hydrogel formation — in fact serve as key binding sites for tannic acid. A structural feature long regarded as a weakness, it turns out, strengthens the hydrogel when combined with tannic acid.

The storage modulus of the tannic acid-enhanced kappa-carrageenan hydrogel reached approximately 1,632 pascals, more than five times that of pure kappa-carrageenan hydrogel at around 294 pascals. The material can therefore maintain its shape more stably under external pressure or deformation, pointing to improved durability and usability for wound dressings and drug delivery patches.

The research team also achieved rapid degradability and strong adhesion at the same time. In experiments simulating the stomach and intestinal environment of the human body, the tannic acid-enhanced hydrogel degraded relatively quickly while still adhering firmly to skin and rough surfaces. This suggests the material could be used in wound dressings that stay in place during use but break down naturally once their role is complete, as well as in drug delivery patches that release medication stably over a desired period.

"This research demonstrates that the mechanical strength, adhesiveness and degradation behavior of a hydrogel can all be engineered using only naturally derived materials," Lee said. "It could be extended into a safer and simpler natural polymer gel platform across the food, cosmetics and biomaterials sectors."

The findings were published April 21 in Biomimetics, an international journal focused on bioinspired research.


nbgkoo@heraldcorp.com