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Researchers have developed a new type of hydrogel that is not only strong but also capable of healing itself in just a few hours. This major breakthrough could pave the way for advancements in artificial skin, robotics, and medical treatments.
The Challenge of Mimicking Human Skin
Hydrogels are commonly found in everyday products such as hair gels and food items. While human skin has some gel-like properties, it is far more complex. It is both firm and flexible and has the remarkable ability to repair itself within 24 hours of an injury.
So far, artificial gels have only been able to copy one of these features—either toughness or self-healing. However, a research team from Aalto University in Finland and the University of Bayreuth in Germany has successfully created a hydrogel that does both. This innovation could lead to significant improvements in areas like drug delivery, wound healing, and flexible robotics.
The Science Behind the Discovery
The researchers achieved this breakthrough by reinforcing the hydrogel with ultra-thin clay nanosheets. Normally, hydrogels are soft and fragile, but the introduction of these nanosheets allowed the gel to form a tightly entangled structure of polymers. This not only made the hydrogel much stronger but also gave it the ability to repair itself when damaged.
Their findings were published in the prestigious journal Nature Materials on March 7, 2025.
A Simple Yet Effective Process
The process of creating this advanced hydrogel is surprisingly simple—similar to baking. Postdoctoral researcher Chen Liang mixed a powder of monomers with water containing the nanosheets. This mixture was then exposed to ultraviolet (UV) light, much like the UV lamps used for setting gel nail polish.
“The UV radiation causes the individual molecules to bind together, turning the liquid into a solid gel,” explained Liang.
Hang Zhang from Aalto University further elaborated, “Entanglement means that the thin polymer layers twist around each other like tiny wool yarns but in a random pattern. When fully entangled, the polymers become indistinguishable from each other. They remain highly dynamic and mobile at a molecular level, so when the gel is cut, the polymers start to intertwine again.”
Fast and Complete Self-Healing
In just four hours, the hydrogel repairs itself by about 80-90%, and within 24 hours, it is completely restored. This remarkable self-healing ability is due to the presence of 10,000 layers of nanosheets within a one-millimeter-thick hydrogel. As a result, the material matches the stiffness, stretchability, and flexibility of human skin.
“Creating a hydrogel that is both strong and self-healing has been a long-standing challenge,” Zhang stated. “We have discovered a mechanism that strengthens the traditionally soft hydrogel, which could lead to the development of new materials with properties inspired by nature.”
Inspired by Nature for Future Innovation
Professor Olli Ikkala from Aalto University emphasized the importance of learning from biological materials to improve synthetic ones. “This research shows how nature can inspire us to design materials with entirely new combinations of properties. Imagine robots with tough, self-healing skins or artificial tissues that can repair themselves without human intervention.”
While this breakthrough is still in the early stages of research, it represents a significant step forward in materials science. “It’s the kind of fundamental discovery that could redefine the rules of material design,” Ikkala added.
The Research Team Behind the Breakthrough
The study, titled “Stiff and self-healing hydrogels by polymer entanglements in co-planar nanoconfinement,” was conducted by an international team led by Dr. Hang Zhang, Professor Olli Ikkala, and Professor Josef Breu. The synthetic clay nanosheets used in the hydrogel were designed and produced at the University of Bayreuth in Germany.
Future Applications and Impact
This hydrogel’s ability to self-repair and maintain its strength could have widespread applications. In the medical field, it could lead to better wound dressings, prosthetic skin, and tissue engineering solutions. In robotics, self-healing materials could enhance the durability of soft robots, reducing maintenance and repair costs.
Though more research is needed before real-world applications become a reality, this development is a game-changer in materials science and bioengineering.
