Harvard University researchers created 4D-printed flowers as the newest examples of 4D printing. The process could soon lead to the formation of synthetic organs to save lives.
The so-called 4D printing is where 3D printed objects can alter their shapes in the course of time and move in such a way that they copy natural processes. Past efforts of 4D printing made use of various materials to form the firm, folded parts of a 3D object.
However, a team of researchers from Harvard University's Wyss Institute for Biologically Inspired Engineering and the Harvard John A. Paulson School of Engineering and Applied Sciences wanted to take a page from Mother Nature's book, particularly in the natural architecture that makes up a flower's transformations.
Led by senior author Jennifer Lewis, the team set out to copy the blueprint of plants cells made up of motion-restricting cellulose fibers. Using a wood pulp's cellulose fibers mixed with acrylamide hydrogel, they created a jelly-like substance.
When submerged in water, the substance expands. They extruded the substance through the nozzle of a 3D printer. This process pushed the fibers to align with the gel, limiting the range of movement to only lengthways. The team came up with a mathematical model that prints out curved shapes.
"Depending on how we actually print the material, we can encode bending, twisting and ruffling," said Lewis.
The research team printed out two, identical flower shapes. The exposed the flowers to water and bent the five petals in various directions. They also printed out an orchid design, which resembles the real flower when the petals were bent. To give the flowers a nice glow, they added a fluorescent dye. This also made the printed design easier to see.
"This work represents an elegant advance in programmable materials assembly, made possible by a multidisciplinary approach," added Lewis.
The technology can lead to applications in the medical field, especially in tissue engineering that can lead to the creation of synthetic organs. Perhaps one day, major organs can be printed out flat, which can then convert itself into the needed shape. The findings were published in the journal Nature Materials on Jan. 25.
