Image Courtesy of Kara Tao.
People constantly anthropomorphize objects. We look at a chair with two buttons and a line and see a face. We bump into our dresser and apologize as if it had feelings. At the end of the day, we know they are not alive, but new research conducted by researchers at Eidgenössische Technische Hochschule (ETH) Zürich and Delft University of Technology could soon change this assumption.
Professor Kunal Masania of Delft University of Technology and Professor Andre Studart of ETH Zürich, along with their colleagues, have created a 3D-printed material out of living fungi that has the ability to self-heal. “The most frustrating thing about making structural materials is that you are really limited by the design complexity that you can come up with, and biological materials don’t have that problem,” Masania said.
Fungi contain mycelia, which are rootlike structures that grow underneath mushrooms and absorb nutrients from the soil. More importantly, mycelia can form a complex signaling network. The researchers mixed individual cells of this mycelia from the fungi Ganoderma lucidum into an ink called a hydrogel, which can then be fed into a 3D printer and used to create different types of structures. “When you let the structure grow, all these cells reconnect and form all of the signaling networks they had as a living organism before,” Masania said.
This signaling network is what gives the material its remarkable regenerative and growing abilities. But how does it work? The answer lies with hyphae—elongated cells in mycelia that catch nutrients from the environment and expel waste. This process creates a chemical gradient that tells the organism where nutrients and space are, and thus where to grow. “That is really something special that you cannot do any other way, even with 3D printing,” Masania said.
Currently, the material can heal gaps up to three millimeters across. However, the fungi on its own has been shown to fill gaps of ten millimeters or more in larger organisms, so there is room to improve. That improvement would come with more advanced work on the biological component of the material.
The material’s lifespan is dependent on three factors: sugar, water, and space. But even without one of these requirements, the material will not die—instead, it will go dormant. It is extremely resilient and can later be reactivated with the return of the missing requirement. The mycelia network was even able to survive accidental contamination in the lab, showing that it is strong as well as forgiving to researchers.
This fungi material can be used for robotics—specifically soft robots, which are made of malleable skins as opposed to firm metal. Soft robotics is a relatively new field with exciting medical and industrial applications since they have increased range of motion and flexibility. The researchers created a robotic grasper that could pick up items and a rolling mechanism that would allow a robot to move. “It can protect the robot from the environment, but it can also protect the environment from the robot, and then it’s regenerative, so if it is damaged it will repair itself,” Masania said.
Potentially even more exciting than the material’s regenerative properties is the potential to harness the mycelia’s chemical signaling mechanism in conjunction with artificial intelligence, which is the subject of the lab’s future research. By placing electrodes on the material, the action potential (a change of voltage across a membrane) produced by the chemical signaling can be recorded, similar to those created by neurons in our brains. The goal is to separate the chemical signaling caused by the normal biological processes of the organism and those specifically caused by environmental triggers.
By separating out the signals caused by environmental triggers such as fungi growth from its sensing of nutrients, the researchers would be able to use these signals to collect environmental data, such as the locations of such nutrient sources. Moreover, they could play back these signals to the organism to gain control of its functions. For instance, researchers could replicate the signal for nutrients in a certain part of the material, causing the mycelia to grow in certain directions—essentially brainwashing a living organism to do their bidding.
Your fridge may not have feelings just yet, but a world full of soft robots with self-healing, growing, living skin may be on the horizon.