Researchers create living material based on algae

Researchers led by Delft University of Technology (TU Delft) used 3D printing to create a novel, environmentally-friendly and living material made of algae that has many potential applications.

Living materials, which are made by housing biological cells within a non-living matrix, have gained popularity in recent years as scientists recognize that often the most robust materials are those that mimic nature.

For the first time, researchers across different TU Delft faculties used 3D printers and a novel bioprinting technique to print algae into living, photosynthetic materials that are tough and resilient. The material has a variety of potential applications. The research has been published in the journal Advanced Functional Materials.

"The printing of living cells is an attractive technology for the fabrication of engineered living materials.” says Marie-Eve Aubin-Tam, an associate professor from the Faculty of Applied Sciences. “Our photosynthetic living material has the unique advantage of being sufficiently mechanically robust for applications in real-life settings.”

Living and non-living components

The researchers began with a non-living bacterial cellulose—an organic compound that is produced and excreted by bacteria. Bacterial cellulose has many unique mechanical properties, including its flexibility, toughness, strength, and ability to retain its shape, even when twisted, crushed, or otherwise physically distorted.

The bacterial cellulose is like the paper in a printer, while living microalgae acts as the ink. The team used a 3D printer to deposit living algae onto the bacterial cellulose.

The combination of living (microalgae) and nonliving (bacterial cellulose) components resulted in a unique material that has the photosynthetic quality of the algae and the robustness of the bacterial cellulose; the material is tough and resilient while also being eco-friendly, biodegradable, and simple and scalable to produce. The plant-like nature of the material means it can use photosynthesis to “feed” itself over periods of many weeks, and it is also able to be regenerated—a small sample of the material can be grown into more on-site.

Artificial leaves and sense-and-respond materials

The unique characteristics of the material make it an ideal candidate for a variety of applications, including new products such as artificial leaves, or sense-and-respond materials.

Artificial leaves are materials that mimic actual leaves in that they use sunlight to convert water and carbon dioxide—a major driver of climate change—into oxygen and energy, much like leaves during photosynthesis. 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. In contrast to most existing artificial leaf technologies, which are produced using toxic chemical methods, the artificial leaves produced by Aubin-Tam and her colleagues are made from eco-friendly materials.

“We created a material that can produce energy simply by placing it into the light,” says Kui Yu, a Ph.D. student involved in the work. “The biodegradable nature of the material itself and the recyclable nature of microalgal cells make it a sustainable living material.”

Besides being fabricated in a sustainable manner, the living cells in the materials can be used to sense and respond to cues in the environment, eventually enabling the development of a new class of photosynthetic and responsive living materials.

“What if our everyday products were alive: could sense, grow, adapt, and eventually die? This unique collaborative project shows that this question is beyond the realm of speculative design. We hope our article will spark new conversations between design and science communities and inspire new directions for investigations for future photosynthetic living materials,” says Elvin Karana, from the Faculty of Industrial Design Engineering.