3D printed cell-opening mechanism opens new possibilities in camouflage, drug delivery

Oct 20, 2017 | By Benedict

Researchers at the University of New Hampshire have used 3D printing to design a unique sequential cell-opening mechanism that could be used for drug delivery and color-changing camouflage materials.

When you think of animals changing color, your mind will likely wander to one creature in particular: the chameleon. In fact, so well-known is this lizard’s ability to change its appearance, we’ve even started using the term “chameleon” in a figurative sense to describe people who change their attributes or beliefs depending on where they are.

But chameleons certainly aren’t the only color-changing creatures in the animal kingdom. Look under the sea, and you’ll find a whole range of incredible cephalopods—squid, cuttlefish, and octopi, for example—who can also change their appearance to disguise themselves.

It’s these aqua-dwelling camouflage creatures that have inspired researchers at the University of New Hampshire to develop a nature-inspired cell-opening mechanism that could be used to make synthetic color-changing smart materials.

The researcher’s exciting new concept involves modifying the chiral geometry of two different cells that are designed to mimic the color-changing organs in cephalopods. When loaded in one direction only, the two different cells open sequentially, producing a color-changing effect.

“We used two different types of cells: one would open right away, and the other would rotate first before opening in the sequence,” explains Yaning Li, assistant professor of mechanical engineering at UNH, and one of the authors of the study.

“What makes this unique is that if each cell is assigned a different color, you could alter the sequential opening mechanism to create a material that might be dark green when the first cell opened and then change to bright yellow when the second one opened after it.”

And this unique mechanism—prototyped with the help of 3D printing—isn’t only useful for changing the color of things. The researchers say “smart materials” made with the cell-opening mechanism could be made responsive to external conditions like light, temperature, and humidity, and could also be made into sensors, opening up a whole range of functional applications.

The mechanism, Li says, could even be used for drug delivery and “particle release, such as two different medicines being released sequentially through a bandage to help address medical issues like wound swelling.”

The University of New Hampshire researchers used a multi-material 3D printer to develop their “hybrid auxetic chiral mechanical metamaterials,” and the flexible additive manufacturing process has allowed them to experiment with their creation.

For example, one application of the process involved developing an innovative soft meta-material whose chiral geometry is customized at two different levels.

“The order of the cell opening can also be altered via geometry and material combination[s] to alter the behavior of the cells and increase the number of potential applications,” said Yunyao Jiang, a doctoral candidate in mechanical engineering at the university, and lead author of the study.

It seems an odd combination, but octopi and 3D printing might just have produced the next big medical innovation.

The study, “Novel 3D-Printed Hybrid Auxetic Mechanical Metamaterial with Chirality-Induced Sequential Cell Opening Mechanisms,” was supported by an NSF/CAREER award. It has been published in Advanced Engineering Materials.

Posted in 3D Printing Application

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