An international team from University of Rochester and Delft University of Technology used 3D printers and a novel bioprinting technique to turn algae into a resilient photosynthetic material.

We may even wear it someday, according to Anne Meyer, a researcher and professor at the University of Rochester.

"Our material feels a bit like canvas, thanks to the bacterial cellulose onto which we print the microalgae," Meyer told Tech Briefs. "It's a tough, flexible material that feels somewhere between thick paper and cotton."

Aside from being a future fashion statement, however, the "living material" also has applications in the energy and fashion sectors.

The material, highlighted in the journal Advanced Functional Materials, could someday support applications like artificial leaves, photosynthetic skins, or photosynthetic bio-garments.

"We provide the first example of an engineered photosynthetic material that is physically robust enough to be deployed in real-life applications," said Srikkanth Balasubramanian, a postdoctoral research associate at Delft and the first author of the paper .

The photosynthetic material contains living and non-living components: microalgae and bacterial cellulose, respectively. The researchers used a 3D printer to deposit living algae onto the bacterial cellulose. Think of the microalgae as ink and the cellulose as the printer paper.

Bacterial cellulose — an organic compound that is produced and excreted by bacteria — has many unique mechanical properties. The organic compound is flexible, tough, and can retain its shape, even when twisted or crushed.

The combination of living and nonliving components resulted in a material that has the photosynthetic quality of the algae and the robustness of the bacterial cellulose; the finished product is tough and resilient while also eco-friendly, biodegradable, and simple to make.

The microalgae-and-cellulose combo may be best suited for "artificial leaves"— materials that use sunlight to convert water and carbon dioxide into oxygen and energy. The leaves store energy in chemical form as sugars, which can then be converted into fuels.

Artificial leaves therefore offer a way to produce sustainable energy in places where plants don't grow well, including outer space colonies.

"For artificial leaves, our materials are like taking the 'best parts' of plants — the leaves — which can create sustainable energy, without needing to use resources to produce parts of plants -- the stems and the roots -- that need resources but don't produce energy," says Meyer . "We are making a material that is only focused on the sustainable production of energy."

(Learn about another development from Meyer's lab in the video below.)

In a short Q&A with Tech Briefs below, Meyer explains more about the promise of living materials, and if we'll actually be wearing them.

Tech Briefs: To start, what’s your response to the question that your recent University of Rochester news release poses: Will your future clothes be made of algae? 

Prof. Anne Meyer: I think that our 3D printed microalgae certainly could be worn as clothing, especially for artistically-minded people who are interested in the unique aesthetic properties of clothing that would change color over time as the algae grows and becomes greener.

Tech Briefs: Why is this kind of “living material” so important to make?

Prof. Anne Meyer: Living materials are exciting because they can combine the best properties of materials, like toughness and durability, with the ability of living organisms to sense and respond to their environment. Bringing living materials into reality opens up the possibility of materials that can alert the user to toxic chemicals in the environment, that can sequester or break down toxins, or that can generate beneficial products when needed. These materials could even use the power of living organisms to be self-healing or to regenerate or duplicate themselves.

Tech Briefs: What do you think will be the main use for this material?

Prof. Anne Meyer: I think that the main application of our new material will be as a way to produce and store solar energy in real-world environments. Since our materials are so robust, they will be better suited to be exposed to changing outdoor weather conditions while soaking up the sunlight and converting it to stored energy.

Tech Briefs: Has algae been printed before in this way?

Prof. Anne Meyer: Our material is a major step forward from previous bioprinted algae materials because the bottom layer of bacterial cellulose makes the final material so tough and durable. In contrast, printed algae that doesn't include the cellulose layer is crumbly and fragile, with little potential for integration into real-world products.

Tech Briefs: How challenging is it to make this material?

Prof. Anne Meyer: Our material is very straightforward to produce since it mostly grows by itself. To produce the cellulose layer, we only need to let our cellulose-producing bacteria grow in a beaker on a benchtop for several days and then harvest and clean the cellulose layer that develops on the top of the culture. Our 3D bioprinter is straightforward to produce, by repurposing an off-the-shelf plastic printer to extrude "bio-ink" instead. Then once we deposit the microalgae-containing bio-ink onto the cellulose, the algae will continue to grow and divide independently.

Tech Briefs: There are variety of additional applications that are possible with this kind of material, like an artificial leaf. Which application, or applications, are most exciting to you and why?

Prof. Anne Meyer: I'm very excited about the potential of developing artificial leaves with our technology. Our photosynthetic materials are able to convert sunlight and carbon dioxide to stored energy in a way that is very simple and passive. While some artificial leaves currently being developed require toxic chemicals or complicated machinery to produce, our printed microalgae are highly sustainable and easy to fabricate. I expect that they would produce energy more efficiently than traditional plants, since they don't need to use any of their resources in making stems, branches, or roots; essentially microalgae is 100% "leaves," or photosynthetic tissue. These materials could therefore be great options for producing energy in space- or resource-limited environments such as in under-water or space colonies.

What do you think? Share your questions and comments below.