Harvard researchers have developed a 3D printing method that applications comfortable filaments to bend, twist, increase, or contract in response to warmth, producing what the crew calls synthetic muscle tissue. 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 strategy, referred to as rotational multimaterial 3D printing, works by extruding two supplies facet by facet via 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 crew has already printed filaments as small as roughly 100 microns in diameter. First creator Mustafa Abdelrahman, a postdoctoral researcher, stated he was drawn to the platform’s flexibility: “I noticed this actually lovely [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 go via; 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 carry 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 pupil and co-author Jackson Wilt pointed to additional prospects: “By way of scalability, you could possibly create extra advanced nozzles that combine with different supplies sooner or later — like, having a liquid metallic 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 stated.
Potential functions embrace comfortable robotic grippers that may manipulate a number of objects directly, energetic valves whose movement pathways will be tuned with temperature, and injectable filaments that lock collectively to type porous, high-surface-area buildings for biomedical makes use of resembling fast tissue clotting. The Harvard Workplace of Expertise Improvement has already moved to guard the analysis and is pursuing commercialization. Federal funding got here from the NSF via the Harvard MRSEC (DMR-2011754) and the ARO MURI program.
Supply: seas.harvard.edu
