"Inspired by Bones" KAIST Develops New Material That Gets Stronger with Use

Bones have the characteristic of becoming stronger by increasing bone density through the synthesis of minerals in the blood when subjected to load. Inspired by this principle, a biomimetic technology has been developed to create a new material that becomes harder the more it is used.

On the 20th, KAIST announced that Professor Seonghun Kang's research team from the Department of Materials Science and Engineering, in collaboration with Johns Hopkins University and Georgia Institute of Technology, developed this new material based on the same principle.

Professor Kang Sung-hoon. Provided by KAIST

The joint research team developed the new material based on the characteristic that when stress is applied to bones during physical activities such as exercise, minerals are formed through cellular activity, making the bone stronger.

To replace cellular activity, they created a porous piezoelectric (converting mechanical force into electricity) substrate that generates more charge as more force is applied, then made a composite material by filling it with an electrolyte containing mineral components similar to those in blood. In this process, the new material synthesizes minerals and increases its strength by itself when stress is applied, without relying on cellular activity.

After applying periodic forces to the material and measuring changes in its properties, the joint research team confirmed that both the stiffness and energy dissipation capacity of the material improved proportionally to the frequency and magnitude of the stress.

This characteristic is evident in the formation of minerals inside the porous material in response to repetitive stress, which dissipates energy by breaking under large forces, but reforms minerals when stress is applied again. The joint research team demonstrated the properties of the new material by capturing its internal structure using micro-CT.

Comparison data of property changes between the new material developed by the joint research team and other existing materials. Provided by KAIST

This contrasts with existing materials, whose stiffness and shock absorption capabilities decrease with repeated use, highlighting the advantage of this new material that simultaneously improves stiffness and shock absorption the more it is used.

In particular, this material enhances its properties proportionally to the magnitude and frequency of the applied stress, allowing it to self-adjust to have a mechanical property distribution suitable for the intended use of the structure, and it also possesses self-healing capabilities.

Professor Seonghun Kang said, “The new material developed through this research has the characteristic of improving stiffness and shock absorption with repeated use, and it can be applied in various fields such as artificial joints, aircraft, ships, automobiles, and structures.”

Meanwhile, this research was conducted jointly with the Extreme Materials Research Institute at Johns Hopkins University and Georgia Institute of Technology, supported by the Brain Pool Plus program of the National Research Foundation of Korea to attract outstanding foreign scientists.

The research results, with Professor Seonghun Kang as the corresponding author, were published this month (Volume 11, Issue 6) in the international journal Science Advances.

This content was produced with the assistance of AI translation services.