In the lab, Kyungsuk Yum fabricates manmade life-like materials. Credit: UT Arlington

Scientists may have devised a way to improve how soft engineering systems and devices are designed and fabricated for bioinspired soft robots, artificial muscles, biomimetic manufacturing and programmable matter.

A research team from the University of Texas at Arlington (UTA) has created a new method where 2D hydrogels can be programmed to expand and shrink in a space-and-time controlled way that applies force to their surfaces, enabling complex 3D shapes and motions to form.

“We studied how biological organisms use continuously deformable soft tissues such as muscle to make shapes, change shape and move because we were interested in using this type of method to create dynamic 3D structures,” Kyungsuk Yum, PhD, an assistant professor in UTA's Materials Science and Engineering Department, said in a statement.

Yum, along with doctoral student, Amirali Nojoomi, used temperature-responsive hydrogels with local degrees and rates of swelling and shrinking, allowing the researchers to spatially program how they swell or shrink in response to temperature change using a digital light 4D printing method that includes time.

This new method enabled the team to print multiple 3D structures simultaneously in a one-step process. Yum then mathematically programed the structures’ shrinking and swelling to form 3D shapes, including saddle shapes, wrinkles and cones, as well as its direction.

The researchers also created some design rules to create more complex structures, including bioinspired structures with programmed sequential motions. The rules, based on the concept of modularity, enabled the researchers to make the shapes dynamic that can move through space.

This also enables the researchers to control the speed the structures change shape, creating complex, sequential motions.

 "Unlike traditional additive manufacturing, our digital light 4D printing method allows us to print multiple, custom-designed 3D structures simultaneously,” Stathis Meletis, PhD, chair of the Materials Science and Engineering Department, said in a statement. “Most importantly, our method is very fast, taking less than 60 seconds to print, and thus highly scalable.

“Dr. Yum's approach to creating programmable 3D structures has the potential to open many new avenues in bioinspired robotics and tissue engineering,” he added. “The speed, with which his approach can be applied, as well as its scalability, makes it a unique tool for future research and applications.”

The study was published in Nature Communications.