Researchers Reverse Engineer the World of Flowers in Biomimetic 4D Printing

3D printing certainly isn’t going out of style—or going anywhere at all—except for perhaps heading onward and upward into another dimension when prescribed. As innovations have continued to evolve into intuitive, smart materials and products, the terms 4D and 4D printing have been pretty well solidified. This dimension could certainly be described as more fluid in the eyes of many, especially in this latest example, created by scientists at Harvard, as they offer up new material that is able to shape-shift with some help from nature–and a lab.

Previously, we’ve seen novelty items that are able to transform in water, such as the 3D printed haiku art that we reported on last year, but this latest from Jennifer Lewis of Harvard University is based on a scientific study just completed, regarding the fabrication of 3D printed items that are almost intuitive, and able to respond and change as needed for a variety of uses.

Lewis and her team also harkened back to nature, using flowers and botany in general as inspiration. Reaching for something more refined than other formal 4D projects out there that rely on stiffer folded materials, with multiple processes and textiles to reach the end product, Lewis and her team of researchers from both the Wyss Institute for Biologically Inspired Engineering at Harvard University and the Harvard John A. Paulson School of Engineering and Applied Sciences looked toward the structures of plants and their cells.

“We set out to take a page from nature, and think about the complex shape transformations that one sees in natural architectures like flowers,” says Lewis, senior author on the new study, ‘Biomimetic 4D printing,’ also authored by A. Sydney Gladman, Elisabetta A. Matsumoto, Ralph G. Nuzzo, and L. Mahadevan.

 

“This work represents an elegant advance in programmable materials assembly, made possible by a multidisciplinary approach,” said Lewis. “We have now gone beyond integrating form and function to create transformable architectures.”

And as has been the case throughout the ages, these scientists are using nature quite logically to work on medical breakthroughs in areas like the construction of 3D printed implants, which are already working wonders for patients all over the world. While mimicking the plant cells, the team was challenged to deal with how their cellulose fibers limit range of motion. They went to work in making a material consisting of wood and acrylamide hydrogel, a gel that expands under water.

“When combined with a minimal theoretical framework that allows us to solve the inverse problem of designing the alignment patterns for prescribed target shapes, we can programmably fabricate plant-inspired architectures that change shape on immersion in water, yielding complex three-dimensional morphologies,” state the authors in their paper, recently published in the journal, Nature Materials.

“Depending on how we actually print the material, we can encode bending, twisting and ruffling,” says Lewis.

Due to what essentially becomes 3D printing ink–being encoded with anisotropic swelling and stiffness, scientists are able to achieve the forms necessary for a variety of uses not just in medicine, but also smart textiles, soft electronics, and tissue engineering. The resulting material to be extruded allows for vertical extrusion, but not horizontal. They also made a separate model for making curved shapes, manipulated to their exact requirements.

These materials could be used for very complex uses medically, allowing for implants that feasibly could fold into a range of shapes upon temperature variances, and could even work as electronics.

“What’s remarkable about this 4D printing advance made by Jennifer and her team is that it enables the design of almost any arbitrary, transformable shape from a wide range of available materials with different properties and potential applications, truly establishing a new platform for printing self-assembling, dynamic microscale structures that could be applied to a broad range of industrial and medical applications,” said Wyss Institute Founding Director Donald Ingber, M.D., Ph.D.

While it’s certainly fulfilling for researchers to look toward nature and find solutions, the results to be found as they basically reverse engineer botany, and flowers in particular, reveal incredibly malleable materials with potential too important to ignore. While these fluid, fabricated flowers and plants may initially appear as rather delicate concepts and examples, the outcome of this study may indeed one day offer individuals substantial new strength due to breakthroughs in medicine that improve the quality of lives—and perhaps save them altogether. Discuss your thoughts on how researchers were inspired by natured in the 4D Printed BioMimicry Flowers forum over at 3DPB.com.