It is well known that 3D printing can be done with any numbers of unusual materials including cells, chocolate and more. But what about bacteria? Well, in a recent project, EPFL (École Polytechnique Fédérale de Lausanne AKA the Swiss Federal Institue of Technology Lausanne) researchers have done just that. More specifically, they have published a method for 3D printing with an ink that contains a calcium carbonate-producing bacteria. The resulting biocomposite has a number of interesting applications and is strong, light and environmentally friendly.
This is certainly not the first time that scientists have turned to the wider natural world to seek solutions for additive manufacturing. In fact, biomimicry, or the practice of imitating life, is popular in 3D printing as it allow for more optimization of parts, such as with lattice structures which imitate beehives. A similar reasoning is behind this project. The researchers looked towards nature which is able to produce composite materials that are simultaneously light and strong, porous and rigid (nearly impossible to do in a lab or factory) such as with mollusk shells or bone. Ultimately, they hope to produce materials that have these properties while also being environmentally friendly. Now with this this 3D printable ink, they have achieved just that.
By combining a bacteria-loaded ink (called BactoInk) and 3D printing, the scientists have successfully created a strong, light and environmentally friendly biocomposite
3D Printing Bacteria to Create Better Composites
In the paper published in Materials Today, 3D printing of living structural biocomposites, researchers at EFPL’s Soft Materials Laboratory, outlined how they were able to create the process. Namely, they created a 3D printable ink using the bacterium Sporosarcina pasteurii. This bacterium was chosen because it has an interesting ability, when exposed to a urea-containing solution, a mineralization process that produces calcium carbonate (CaCO3) is triggered. The new ink, dubbed BactoInk, is capable of printing virtually any shape and then will mineralize over the course of a few days.
The choice to use an ink that would mineralize was due to a need to get around issues often centered on 3D printing with inks (namely that they can be difficult to manage as they require certain flow conditions and also tend to be soft or shrink after printing). The Soft Materials Lab head, Esther Amstad explained, “So, we came up with a simple trick: instead of printing minerals, we printed a polymeric scaffold using our BactoInk, which is then mineralized in a second, separate step. After about four days, the mineralization process triggered by the bacteria in the scaffold leads to a final product with a mineral content of over 90%.”
Co-authors and Soft Materials Lab researchers Matteo Hirsch and Lorenzo Lucherini
The result is a strong and resilient biocomposite that can even be produced using a standard 3D printer. Moreover, the final products no longer contain living bacteria. The material is also particularly interesting because it is not only strong and light, but porous which can be quite difficult to achieve with additive manufacturing.
The researchers have already outlined a number of applications for the material in different fields. One application is of course the restoration of artworks, as the ink could be directly injected into the site and then just grow to fit the crack or chip. But thanks to its use of environmentally friendly materials, it could also be very exciting for building artificial corals in order to regenerate damaged marine reefs, a pressing environmental concern.
Amstad, concludes, “The versatility of the BactoInk processing, combined with the low environmental impact and excellent mechanical properties of the mineralized materials, opens up many new possibilities for fabricating lightweight, load-bearing composites that are more akin to natural materials than to today’s synthetic composites.” If you would like to learn more, you can find the full study HERE.
What do you think of the EPFL researchers’ work in using bacteria-loaded ink and 3D printing to create biocomposites? Let us know in a comment below or on our LinkedIn, Facebook, and Twitter pages! Don’t forget to sign up for our free weekly Newsletter here, the latest 3D printing news straight to your inbox! You can also find all our videos on our YouTube channel.
*All Photo Credits: Eva Baur/EPFL