Engineers create bio-inspired, silk-based materials with programmable traits

From its discovery in the fourth millennium BCE, silk production was a guarded Chinese secret for thousands of years. Now, researchers from Tufts University have engineered silk fibers to develop materials that can be programmed to respond to their environment.

“In nature, there is a strong interplay between a material’s form and function,” Fiorenzo Omenetto, the senior researcher on the project, told Digital Trends. Due to their particular structures, many biological materials carry qualities like strength, water resistance, and the ability to cool down quickly.

Tufts University

“Structural proteins are the building blocks of nature,” Omenetto said. “Silk, in particular, possesses compelling properties,” including its durability and biocompatibility. Meanwhile, the structure of fibroin enabled the engineers to form it into three-dimensional objects that can sense and respond to the environment, such as surgical pins that change colors when they’re about to break and screws that can be heated with infrared light.

To develop these materials, the engineers began with silk cocoons and dissolved the silk fibers in a solution to create water suspensions of proteins, which were then re-assembled in solid block forms. “We usually experience silk as a fibrillar material,” Omenetto said, “but this format comes from the spinning process to which the protein undergoes in the spinneret of caterpillars and spiders.

“The new format of silk described in the study opens the door to the fabrication of high performing plastic-like materials made of silk fibroin,” he added.

Omenetto and his team need to conduct more research to refine their material but they think it could one day be used to support orthopedic devices that can release medicines or mechanical parts that can sense and convey material failures.

A paper describing their work was published online this week in the journal Proceedings of the National Academy of Sciences.