Living materials made by housing biological cells within a nonliving matrix have gained popularity as scientists recognize that often the most robust materials are those that mimic nature. Researchers have now used 3D printers and a novel bioprinting technique to print algae into living, photosynthetic materials that are tough and resilient.
To create the photosynthetic materials, the researchers began with a nonliving bacterial cellulose — an organic compound that is produced and excreted by bacteria. Bacterial cellulose has many important mechanical properties such as flexibility, toughness, strength, and the 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. A 3D printer was used 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 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's also able to be regenerated — a small sample of the material can be grown onsite to make more materials.
The characteristics of the material make it an ideal candidate for a variety of applications including new products such as artificial leaves, photosynthetic skins, or photosynthetic bio-garments.
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, potentially, outer space colonies.
The artificial leaf materials 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. The material is only focused on the sustainable production of energy. Another application of the material would be photosynthetic skins that could be used for skin grafts. The oxygen generated would help to kick-start healing of the damaged are, or it might be able to carry out light-activated wound healing.
Bio-garments made from algae would address some of the negative environmental effects of the current textile industry in that they would be high-quality fabrics sustainability produced and completely biodegradable. They would also work to purify the air by removing carbon dioxide through photosynthesis and would not need to be washed as often as conventional garments, reducing water usage. The materials can sustain themselves over periods of weeks and can be multiplied onsite, so they have the potential to be long-lasting and able to be shared.