DEC 05, 2017 07:54 PM PST

'Living Tattoo' 3D Printed by Scientists

WRITTEN BY: Carmen Leitch

A new type of 3D printing uses a special ink derived from genetically altered live cells; it has allowed scientists to make a patch, or “living tattoo” of bacterial cells that react to specific compounds. When the patch is applied to skin that has been treated with these same compounds, the pattern lights up with color. These specialized cells can respond to a variety of stimuli and can be printed to form three dimensional devices or structures. 

The work was led by Xuanhe Zhao, the Noyce Career Development Professor in MIT's Department of Mechanical Engineering, and Timothy Lu, an Associate Professor of Biological Engineering and of Electrical Engineering and Computer Science. They said that this process would enable the fabrication of "active" materials, like wearable sensors and interactive displays. These elements can be aligned with engineered cells, to survey chemicals in the environment as well as shifts in pH and temperature.

This technology was used by the researchers to create a model that predicts how cells interact in a 3D-printed structure under various conditions. That will help scientists who are designing live materials that can sense and respond. The study has been reported in Advanced Materials.

While there have been other attempts in this area, they have not been successful because mammalian cells are not robust enough to stand up to the rigors of 3D printing. "It turns out those cells were dying during the printing process because mammalian cells are basically lipid bilayer balloons," explained co-author Hyunwoo Yuk. "They are too weak, and they easily rupture."

Bacterial cells were a good option. They have a sturdy cell wall, and they are compatible with hydrogels, a matrix of water and polymer used in 3D printing. After the team put in a lot of work selecting the cells and finding the most compatible hydrogel, they settled on plutonic acid. 

"This hydrogel has ideal flow characteristics for printing through a nozzle," Zhao said. "It's like squeezing out toothpaste. You need [the ink] to flow out of a nozzle like toothpaste, and it can maintain its shape after it's printed." 

They went on to create an ink containing the hydrogel and cells, along with nutrients. With a unique printer made by the team, the patch, a pattern of cells in the shape of a tree, was made and tested on human skin. The bacterial cells in the patch were shown to be responsive to a chemical stimulus. 

A screenshot from the video above

Yuk suggested that researchers may use this technique one day to make "living computers,” which are comprised of multiple cell types interacting with one another, passing signals like the transistors of a microchip.

"This is very future work, but we expect to be able to print living computational platforms that could be wearable," Yuk said.

In the near-term, the researchers want to engineer stickers or patches that are customized sensors of various molecular compounds. They are hopeful that another application is in the manufacture of drug capsules or medical implants, with cells engineered to produce chemicals like glucose, and release them in a controlled way.

"We can use bacterial cells like workers in a 3-D factory," Liu said. "They can be engineered to produce drugs within a 3-D scaffold, and applications should not be confined to epidermal devices. As long as the fabrication method and approach are viable, applications such as implants and ingestibles should be possible."


Sources: AAAS/Eurekalert! Via MIT, Advanced Materials

About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
OCT 29, 2018
Neuroscience
OCT 29, 2018
Zapping the nerves to promote nerve regeneration
Nerve regeneration by electrical stimulation...
NOV 05, 2018
Videos
NOV 05, 2018
The Mechanisms Underlying the Deadly Blow of the Mantis Shrimp
The mantis shrimp packs a powerful punch that can strike its enemies with one of the fastest moves in the animal kingdom....
NOV 10, 2018
Videos
NOV 10, 2018
Engineering Viable Offspring From Same-sex Mouse Parents
Using a special kind of stem cell and genetic engineering, researchers have learned more about what's possible in reproduction....
NOV 12, 2018
Microbiology
NOV 12, 2018
Some Bacteria Gain Resistance Even Without Exposure to Antibiotics
Most bacteria are harmless, some are even beneficial to us. But some of the dangerous ones pose a real threat to public health....
NOV 24, 2018
Genetics & Genomics
NOV 24, 2018
How Fish can Teach us About Mending a Broken Heart
Our world hosts some incredible organisms, some of which might help people create treatments for disease....
NOV 27, 2018
Genetics & Genomics
NOV 27, 2018
Researchers Stunned to Find People who Inherited Mitochondrial DNA From Dad
It was thought that in humans, mitochondrial DNA was passed on exclusively by mothers....
Loading Comments...