3D printable ink containing bacteria will be used in many fields

BactoInk also has a bright future in building artificial corals and regenerating damaged marine reefs.
Nergis Firtina
The method could be used to restore damaged artworks.
The method could be used to restore damaged artworks.

Eva Baur/EPFL 

Researchers at the Swiss Federal Institute of Technology Lausanne (EPFL) devised a method for 3D printing ink containing calcium carbonate-producing microorganisms.

The newly created 3D-printed mineralized bio-composite is incredibly strong, light, and eco-friendly, with various uses in biomedicine and the arts, says EPFL.

They have created the first 3D printable ink with Sporosarcina pasteurii, a bacteria that starts a mineralization process resulting in calcium carbonate (CaCO3) when exposed to a urea solution. As a result, the scientists' ink, called BactoInk, probably be used to 3D-print almost any shape. 

“3D printing is gaining increasing importance in general, but the number of materials that can be 3D printed is limited for the simple reason that inks must fulfill certain flow conditions,” explains lab head Esther Amstad.

“For example, they must behave like a solid when at rest but still be extrudable through a 3D printing nozzle – sort of like ketchup," she adds.

3D printable ink containing bacteria will be used in many fields
A 3D-printed shape using BactoInk will mineralize within a few days.

Amstad notes that while microscopic mineral particles have been added to 3D printing inks in the past to meet some of these flow requirements, the resulting structures have a tendency to be soft or to shrink after drying, which causes cracking and a loss of control over the shape of the finished output.

The power of 'BactoInk'

Amstad states this innovative approach can be applied in several fields, including biology, ecology, and even the arts. Moreover, cracks or chips in a statue can be treated with BactoInk by injecting it right there.

“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,” Amstad says.

EPFL's study was published in Materials Today on February 18.

Study abstract:

Nature fabricates organic/inorganic composites under benign conditions, yet, in many cases, their mechanical properties exceed those of the individual building components it is made from. The secret behind the evolutionary pivot is the unique ability of nature to control structure and local composition of its materials. This tight control is often achieved through compartmentalization of the reagents that can be locally released. Inspired by nature, we introduce an energy-efficient process that takes advantage of the compartmentalization to fabricate porous CaCO3-based composites exclusively comprised of nature-derived materials whose compressive strength is similar to that of trabecular bones. The unique combination of nature-derived materials, 3D printability, and good mechanical properties is achieved through the formulation of these materials: We combine microgel-based granular inks that inherently can be 3D printed with the innate potential of engineered living materials to fabricate bacteria-induced biomineral composites. The resulting biomineral composites possess a porous trabecular structure that comprises up to 93 wt% CaCO3 and thereby can withstand pressures up to 3.5 MPa. We envisage this system to have the potential to be used in art restoration, serve as artificial corals to help the regeneration of marine reefs, and, with additional work, might even allow the reparation of broken or partially disintegrated natural mineral-based materials such as certain parts of bones.

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