The Neel Josh team from Northeastern may have designed a 3D printable material that is alive

Neel Joshi, associate professor of chemistry and chemical biology, and Avinash Manjula-Basavanna, postdoctoral researcher, are working on programmable microbial ink for 3D printing of living materials, in the Mugar Life Sciences building. Photo by Matthew Modoono / Northeastern University

By Eva Botkin-Kowacki

News in the North East

If humans are ever to live on Mars or the Moon, we will need to be able to construct buildings to live, sleep, eat, and work in space. According to space agencies, the way to achieve this is to 3D print habitats or their components. But transporting enough Earth-derived materials used for most 3D prints from our planet to another celestial body is not a feasible option.

Biology could solve this problem, says Neel Joshi, associate professor of chemistry and chemical biology at Northeastern. And Joshi’s team may have designed the technology for the job: a 3D printable material that is alive.

“As a tree has integrated cells and it goes from seed to tree, assimilating the resources of its environment in order to implement these structural building programs, what we want to do is a similar thing, but where we provide these programs in the form of DNA which we writing and genetic engineering, ”says Joshi.

Researchers figured out how to program the bacteria Escherichia coli, also known as E. coli, to produce a fully organic ink that can be used to 3D print solid structures. This microbial ink, which is described in a document published Tuesday in the journal Nature Communications, has not yet been tested on a cosmic scale, but scientists have used the gelatinous material to print small shapes, such as a circle, a square and a cone. They also successfully programmed it to construct materials with specified attributes along with other applications that could be useful in medicine.

Neel Joshi, associate professor of chemistry and chemical biology, is working on a programmable microbial ink for 3D printing of living materials, in the Mugar Life Sciences building. Photos by Matthew Modoono / Northeastern University

“We want to use living cells, microbes, like factories to make useful materials,” says Avinash Manjula-Basavanna, postdoctoral fellow at Joshi’s laboratory and lead co-author of the new document. The idea, he says, is to harness the unique properties of the materials that make up living things for a variety of purposes, ranging from therapeutic to industrial.

“Think of it as a platform to build a lot of different things, not just bricks for building construction or construction,” says Joshi. He explains the work by comparing it to how a polymer chemist considers how to design plastic materials that can serve distinct purposes. Some plastics are hard and hold their shape, while others are stretchable and flexible.

“Biology is capable of doing similar things,” says Joshi. “Think of the difference between the hair, which is flexible, and the horns of a deer or a rhino or something like that. They are made of similar materials, but they have very different functions. Biology has figured out how to adjust these mechanical properties using a limited set of building blocks. “

The particular natural building block that scientists take advantage of is a protein produced by the bacteria E. coli. The material, called Curli fibers, is produced by bacterial cells when they attach to a surface and to each other to form a community. The same properties that make Curli fibers a kind of glue for bacteria also make them an attractive material for microbial engineers like Joshi and his colleagues.

The researchers 3D printed small shapes using the microbial ink they developed from the bacteria Escherichia coli, also known as E. coli. Image courtesy of Duraj-Thatte et al., Nature Communications

To make the microbial link, scientists started by cultivating genetically modified products E. coli in a bottle. They fed the bacteria with nutrients for them to multiply, and as they separated, they produced the desired polymers, the Curli fibers. Then, the researchers filtered out the gelatinous polymers and fed this material into a 3D printing device as microbial ink.

Microbes have been used in the past to make ink for 3D printing, but, according to Joshi and Manjula-Basavanna, what sets this microbial ink apart is that it is not mixed with anything else. Their gel is entirely organic.

One of the advantages of a truly living material is that it is, in fact, alive, says Manjula-Basavanna. And that means it can do what living things can do, like heal itself, like the skin does. Under the right conditions, the cells in the microbial gel might just grow more.

It’s not necessarily always growing, says Joshi. For example, if the cells were left alive in the little cone the team made from the microbial gel, “if you were to take that whole cone and put it in a solution of glucose, the cells would eat that glucose and make it.” more. of that fiber and grow the cone into something bigger, ”he says. “There is the possibility of taking advantage of the fact that there are living cells there. But you can also just kill the cells and use them as inert material. “

While the initial gel is made entirely from genetically modified products E. coli, the researchers also tried mixing the ink with other genetically modified microbes in an attempt to use the 3D printed materials for specific purposes. This is how they made a material capable of delivering an anti-cancer drug, which it released when it encountered a specific chemical stimulus. In another experiment, they also programmed another material to trap the toxic chemical bisphenol A (BPA) when it encountered BPA in the environment.

“You might think about taking a bottle cap and printing our material on it so that if there was BPA around it would get sucked into it and not be in your drink,” Joshi says.

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