Harvard researchers have developed a 3D printing approach that applications gentle filaments to bend, twist, develop, or contract in response to warmth, producing what the group calls synthetic muscle mass. The work, printed April 29 within the Proceedings of the Nationwide Academy of Sciences, comes from the lab of Jennifer Lewis, the Hansjorg Wyss Professor of Biologically Impressed Engineering at Harvard’s John A. Paulson Faculty of Engineering and Utilized Sciences.
The tactic, referred to as rotational multimaterial 3D printing, works by extruding two supplies facet by facet by way of a rotating nozzle: an “energetic” liquid crystal elastomer that contracts alongside its molecular alignment route when heated above a transition temperature, and a “passive” elastomer that holds its form no matter temperature. As a result of one facet shortens and the opposite resists, even a easy bilayer filament bends. Rotating the nozzle because it prints writes a helical molecular alignment into the filament, letting the researchers exactly pre-program the way it’ll deform when activated. No post-processing is required.
The group has already printed filaments as small as roughly 100 microns in diameter. First creator Mustafa Abdelrahman, a postdoctoral researcher, mentioned he was drawn to the platform’s flexibility: “I noticed this actually stunning [rotational 3D printing platform] and thought, ‘What if we plug in energetic supplies and sample them throughout the filament — can we drive form change that means?’”
Working with these particular person filaments as constructing blocks, the researchers constructed flat lattices able to performing as temperature-controlled filters: warmth them, and the lattice opens to let spherical particles cross by way of; cool them, and it contracts to lure or help the particles. In addition they constructed pick-and-place grippers, free-standing lattices that may be lowered onto a number of rods, heated to grip and raise them, then cooled to launch. In a single take a look at, a lattice printed with alternating increasing and contracting areas morphed right into a dome-like form when heated in an oil bathtub, matching the shape predicted by simulations.
Graduate scholar and co-author Jackson Wilt pointed to additional prospects: “When it comes to scalability, you may create extra complicated nozzles that combine with different supplies sooner or later — like, having a liquid steel channel to allow actuation, or integrating different performance.”
The work was validated in collaboration with Professor L. Mahadevan, whose group focuses on the mechanics of pure buildings, and Professor Joanna Aizenberg, whose lab characterised the liquid crystal elastomers’ molecular alignment utilizing X-ray scattering at Brookhaven Nationwide Laboratory. “This filament design and printing framework may speed up the transition of synthetic muscle-like supplies from the lab to real-world applied sciences,” Lewis mentioned.
Potential functions embrace gentle robotic grippers that may manipulate a number of objects without delay, energetic valves whose stream pathways will be tuned with temperature, and injectable filaments that lock collectively to kind porous, high-surface-area buildings for biomedical makes use of similar to speedy tissue clotting. The Harvard Workplace of Know-how Growth has already moved to guard the analysis and is pursuing commercialization. Federal funding got here from the NSF by way of the Harvard MRSEC (DMR-2011754) and the ARO MURI program.
Supply: seas.harvard.edu