Date:04/12/17

Researchers print “living materials” with bacteria-loaded inks

Researchers at the Swiss Federal Institute of Technology in Zurich (ETH Zurich) have developed a biocompatible ink for 3D printing with living bacteria. The breakthrough makes it possible to produce high-purity biomedical cellulose or biological materials that can break down toxic substances.
 
Picking out a 3D printing filament is generally just like any other shopping experience: you pick your favorite based on its performance and the required application. But imagine if choosing a 3D printing material was more like going to the pet store than the hardware store…
 
That’s a future foreseen by researchers at Swiss university ETH Zurich, who have developed a 3D printing platform that prints with living bacteria—good bacteria, not the kind associated with disease—that gives 3D printed structures incredibly useful functional properties.
 
They’ve called their incredible 3D printable ink “Flink,” which stands for “functional living ink.”
 
According to these researchers, Flink offers huge potential for biochemistry and biomedicine. Choosing the species of bacteria affects the physical properties of what the researchers are calling 3D printed “biochemical factories” or “minifactories,” which can be printed on the platform and used to make things like artificial skin.
 
The forward-thinking research group has already experimented with two different bacteria: Pseudomonas putida, which can break down the toxic chemical phenol, produced on a large scale by the chemical industry, and Acetobacter xylinum, which secretes high-purity nanocellulose that can provide pain relief and moisture retention—properties that make it useful for treating burns.
 
This, however, is just the tip of the bacterial iceberg. The new 3D printing platform can be used to print up to four different bacterial inks in a single pass. And by precisely altering the concentrations of each species of bacteria, objects can be printed with differing physical and functional properties.
 
The 3D printable ink containing these species of bacteria is made up of a biocompatible hydrogel (containing hyaluronic acid, long-chain sugar molecules, and pyrogenic silica), which provides the ink with its printable form. A mixed-in culture medium containing sugars keeps the chosen mix of bacteria alive.
 
And that mix can potentially do brilliant things. For starters, the bacterial ink could be used for advanced biomedical applications like treating burns victims and other patients, with the 3D printing platform able to fabricate cellulose-based 3D wound patches for treating various injuries. 3D printed cellulose could also be used for skin transplants, biosensors, and tissue envelopes, with the neutrality of the substance making it unlikely to be rejected by the human body.
 
But the uses for the 3D printable ink go beyond the hospital. Bacterial 3D printed structures could be used to study degradation processes or biofilm formation, or even used as sensors for detecting toxins in drinking water. 3D printed bacterial “filters” could also be used in oil spills.
 
One of the biggest challenges in developing the bio 3D printing platform was creating a hydrogel that had the right flow properties for 3D printing. Too runny and the material would not form a solid shape; too thick and the 3D printer nozzle would be unable to process it. But these are just the day-to-day challenges of regular 3D printing materials; the researchers also had to ensure that the hydrogel would allow the living bacteria to move around freely.
 
The ideal physical properties of a 3D printable bacteria-filled ink? As viscous as toothpaste, and with the consistency of Nivea hand cream, the researchers say.
 
That wasn’t the only challenge, however. Another long-term obstacle for the researchers is overcoming the slow printing time and difficult scalability of 3D printing with bacteria. It’s something they’ll have to do if they want to implement their process on a wider scale.
 
Additionally, the researchers don’t yet know how long their 3D printed “minifactories” can survive, but—since bacteria don’t need much to live on—they assume it’s a long time.
 
The research, “3D printing of bacteria into functional complex materials,” has been published in Science Advances. Its authors were Manuel Schaffner, Patrick A. Rühs, Fergal Coulter, Samuel Kilcher, and André R. Studart.


 

Views: 441

©ictnews.az. All rights reserved.