Hagfish Serve as Unlikely Inspiration for a New Approach to 3D Printing Fine, Flexible Hair

Researchers from Dankook University, the University of Illinois Urbana-Champaign, the University of Cambridge, Chapman University, and Hongik University have come up with a new approach to 3D printing that allows for the replication of fine hair and fiber-like structures — taking inspiration from the slimy hagfish.

"In nature, there are many examples of filamentous structures that achieve a diameter of only a few microns," explains second author Mohammad Tanver Hossain of the team's work on printing ultra-fine filaments, which drew on spider silk and the defensive thread of the slimy hagfish for inspiration. "We knew it had to be possible."

Typically, 3D printing offers a lower limit to feature size: too fine, and the material will warp or snap. Embedded 3D printing tries to solve this by printing in a gel-like medium, rather than air, to provide additional support — but even then researchers struggled to get prints down as small as the width of a hair.

"We modified the gel and the print ink so that the ink would cure as soon as it gets deposited in the gel," Hossain explains of how the team overcome this previous limit of around sixteen microns in diameter to print at a resolution of just 1.5 microns. "This prevents the filament from snapping because it's almost instantaneously solid."

"This research overcomes a long-standing limitation of 3D printing technology—printing soft materials with a diameter as small as one micron," explains first author Wonsik Eom. "Achieving such high printing resolution means we now have the technological foundation to mimic the microfibers and hair-like structures found in nature, which exhibit remarkable functionalities. Through our research, we discovered that developing high-resolution embedded 3D printing technology enables us to replicate a much wider range of natural structures than we initially expected."

"The significance of this method is to produce many geometries of hairs while not having to deal with the downward force of gravity on such fine and flexible hair," adds corresponding author Sameh H. Tawfick. "This allows us to produce complex 3D hair, having fine diameters, using an ultraprecise 3D printer."

The team's work has been published in the journal Nature Communications under open-access terms.

Main article image courtesy of Mohammad Tanver Hossain.