More and more often, environmentally friendly materials are made from natural substances that replace plastic or rare raw materials. A living biomaterial developed by US researchers goes one step further: living microalgae are integrated into the bacterial cellulose tissue. As a result, this material can actively photosynthesize and could be used for energy generation, as a biotextile or for skin transplants in medicine.
Whether textiles made from vegetable cellulose, floors made from wood residues or insulating materials made from plant fibers – researchers are developing more and more environmentally friendly materials that are made from renewable raw materials instead of plastics or unsustainable resources. Products with integrated living material go one step further, for example in the form of bacteria or algae that drive photosynthesis.
From bacteria and algae to material
Until now, however, most of these “living materials” had the problem that they were not very stable and difficult to manufacture and shape. Scientists working with Srikkanth Balasubramanian from the Technical University of Delft in the Netherlands have therefore now looked for a simpler and more robust alternative. They chose bacterial cellulose as the bio-based support structure of their material. Stable fibers are not only contained in the cell walls of plants, certain bacteria can also form and excrete them outside their cells. The resulting very fine network structure is particularly pure compared to vegetable cellulose and also very flexible and mechanically stable, as the researchers explain. This allows it to maintain its shape even if it is twisted, crushed, or otherwise physically deformed.
The cellulose matrix serves as a substrate for the living components of the new biomaterial. This consists of microalgae that is applied to the cellulose using a 3D printer. This creates a robust, textile-like material that, thanks to the algae, can actively photosynthesize. As tests showed, the living cellulose-algae tissue proved to be robust and long-lasting. The bacterial cellulose gives it sufficient mechanical strength, the algae allow it to photosynthesize and thus “feed” itself over a longer period of time. Bioprinted materials can thus survive stably for at least three days without nutrients and their lifespan can be further extended if they have a fresh source of nutrients within this period, the scientists explain. Another advantage: “These bioprints are regenerative, which means they can be reused and expanded to print other living materials,” report Balasubramanian and his colleagues.
As an energy supplier, medical product and biotextile
“We are providing the first example of an engineered photosynthetic material that is physically robust enough to be used in real applications,” says Balasubramanian. The algae material could have great potential for sustainable energy generation, for example: As “artificial leaves”, it could use sunlight to convert water and carbon dioxide into oxygen and energy – like leaves during photosynthesis. The leaves store the energy as sugar, which can then be converted into fuel. The material thus offers a way of utilizing carbon dioxide from the air and producing environmentally friendly energy in places where plants do not grow well, the researchers explain. “With artificial leaves, our materials are like taking the ‘best parts’ of the plants – the leaves – which can generate sustainable energy without using resources to produce plant parts – the stems and roots that need resources but don’t generate energy, ”says Anne Meyer of the University of Rochester in New York.
And the new material could not only be used as a source of energy: It could also be used as photosynthetic skins for skin transplants, assumes Meyer. “The generated oxygen would help to initiate the healing of the damaged area, or it could enable light-activated wound healing,” says the researcher. In addition, the material could also be used as a biotextile in the fashion industry. The organic clothing made from algae could not only be produced sustainably and completely biodegraded. They would also help clean the air if they utilize the carbon dioxide through photosynthesis, according to the scientists. In addition, according to the researchers, these textiles do not have to be washed as often as conventional items of clothing, which could reduce water consumption.
Source: University of Rochester, Article: Advanced Functional Materials, doi: 10.1002 / adfm.202011162