3D Printing- Harnessing Materials made with 'Living Ink'

 Images adapted from  Freepik  and  Flickr

Images adapted from Freepik and Flickr

Author: Ruchi Maniar Edited by: Ruth Sang Jones

A recent study published in Science Advances demonstrates a pioneering 3D printing approach to produce bacteria-derived functional materials.  A 'living ink' can offer diverse metabolic capabilities derived from bacteria. Combined with the power of additive manufacturing, this ink enables the creation of complex 3D architectures of bacteria-laden hydrogels. The demonstrated platform exhibits full control of the localization and concentration of bacteria. The active ink, called 'Flink',  has the potential to degrade pollutants and/or even produce clinically significant bacterial cellulose.

The functionality of bacteria is incredibly diverse, given the plethora of metablic products they can degrade as well as synthesize. These processes are most evident when bacteria grow in a community as a biofilm. During the growth and adaptation of these communities to their environment, many compounds are naturally synthesized that are applicable ingredients in making chemicals,  bio-polymenrs, enzymes and protiens relevant for the food, medical and chemical industries. Biominerals such as calcium carbonate, magnetites and biopolymers are also direct products made during bacterial growth that have potential use in creating biodegradable plastics and functional materials for biomedical applications. 

Schaffner et al. reveal the potential of 3D-printed bacterial structures for biotechnological applications through the immobilisation of two model bacterial strains: P. putida and A. xylinum in the hydrogel ink.  A printed grid was embedded with an immobilized phenol degrader, P. putida, and placed into phenol-contaminated water. Interestingly, the bacteria degraded phenol into biomass and purified the water.

Another example of added functionality was illustrated by combining Flink loaded with the bacterium A. xylinum, which is capable of producing cellulose when exposed to oxygen in a culture medium.  The researchers were able to print ink of this composition onto the topography of a doll's face- showing the dimensional versatility of the method.  Identified prospective applications of such cellulose reinforced hydrogels are skin transplants or wound dressings. 

The applications of a bacterial ink in a 3D matrix are evidently extensive, ranging from bioremediation to biomedical applications, which were demontrated in this study through rudimentary experiments. In the future, production of these biomaterials must be upscaled outside of the laboratory. Furthermore, this type of bacteria-printing platform shows vast promise to be manipulated to form complex materials with properties otherwise not accessible by standard technologies.

References

1. Schaffner M, Rühs P, Coulter F, Kilcher S, Studart A. 3D printing of bacteria into functional complex materials. Science Advances. 2017;3(12):eaao6804.

2. Hall-Stoodley L, Costerton J, Stoodley P. Bacterial biofilms: from the Natural environment to infectious diseases. Nature Reviews Microbiology. 2004;2(2):95-108.

3. Costerton J, Lewandowski Z, Caldwell D, Korber D, Lappin-Scott H. Microbial Biofilms. Annual Review of Microbiology. 1995;49(1):711-745.

4. Douglas S, Beveridge T. Mineral formation by bacteria in natural microbial communities. FEMS Microbiology Ecology. 1998;26(2):79-88.

5. Bazylinski D, Frankel R. Magnetosome formation in prokaryotes. Nature Reviews Microbiology. 2004;2(3):217-230.

6. Rehm B. Bacterial polymers: biosynthesis, modifications and applications. Nature Reviews Microbiology. 2010;8(8):578-592.

7. Klaus-Joerger T, Joerger R, Olsson E, Granqvist C. Bacteria as workers in the living factory: metal-accumulating bacteria and their potential for materials science. Trends in Biotechnology. 2001;19(1):15-20.

8. Bhuwal A, Singh G, Aggarwal N, Goyal V, Yadav A. Isolation and Screening of Polyhydroxyalkanoates Producing Bacteria from Pulp, Paper, and Cardboard Industry Wastes. 2018.