The Shiny Lackporling can do more than attack trees. Researchers have used the fungus to create a living robot skin and a sustainable alternative to chips and batteries.
The more technologies used today, the more questions arise about how they can become more robust and sustainable. Vacuum cleaner robots, smartphones, and computer circuit boards also have to be disposed of at some point. Sustainable alternatives made from plants or fungi could help here.
Austrian researchers, for example, have developed a circuit board based on the shared tree fungus Shiny Lackporling, as they published in the journal Science Advances.
Circuit boards made from tree fungus
Circuit boards serve as carriers for electronic components and connect them to each other using so-called conductor tracks. The plate itself is made of a stable and electrically insulating material; plastic or silicon is usually used for this. Fungus, on the other hand, can create biodegradable electronic circuit boards that decompose themselves in a very short time, within several weeks.
This is made possible by so-called fungal mycelia. These are the root networks of fungi, which have vast networks of fibers underground. The mycelial skin is used for the circuit boards. The skin of the mushroom mycelia is both heat-resistant, robust and flexible.
Simple and resource-saving production
Production begins with beech shavings, wholemeal spelt flour, gypsum, and water—and with spores of the Shiny Lackporling. The research team from Johannes Kepler University Linz allowed the mycelium to grow on it. In the final step, the skin was peeled away from the mycelium, dried, pressed, and cut to the correct size. Conductor tracks can then be added, and electronic components can be attached as with conventional circuit boards.
According to the research team, circuit board production is more straightforward, requires less energy and water than conventional production, and does not require harmful chemicals. So far, this has produced simple and small printed circuit boards.
The researchers also use the fungal mycelia to make batteries. In such a battery, the mycelium of the shiny lacquer cell can consist of both the membrane between the poles and the cover.
Mushroom mycelium – a complex and adaptive network
In addition to the properties of the mycelial skin in electronics, the mycelium can also be attractive for science. Mushroom mycelium is a living, complex, and adaptable material that forms large networks. These networks, in turn, consist of elongated cells called hyphae. The hyphae absorb water and nutrients, which is how the fungus spreads in nature.
However, in most of the previously known application approaches, the fungi used die at the end of the process or are removed again. Researchers at the Swiss Federal Institute of Technology in Zurich also use the adaptable behaviour to develop self-healing and robust robot skin.
Living robot skin from the 3D printer
As the research team describes in Nature Materials, a three-dimensional grid is printed from a hydrogel using a 3D printer. The hydrogel is loaded with spores of the shiny lacquer pore. If you leave the framework at 23 degrees Celsius and a high relative humidity of 95 per cent for several days, the mycelium grows without the hydrogel drying out.
Within 20 days, the fungal mycelia colonise the printed grid, creating robust and regenerating skin. If this is cut or punctured, it will grow back together. The metabolic activity of the mycelia and the availability of nutrients are responsible for this.
Robot coated with mycelium.
The living robot skin of mycelium is soft, waterproof, regenerative and robust against mechanical influences. This means that the properties of the skin through the mycelium are comparable to some functions of biological animal skins.
The researchers carried out tests with a gripper arm and a ball robot covered with mycelium skin. The robots successfully completed underwater actions or were rolled over different surfaces.
Further research approaches and possible areas of application.
Both research approaches show that the use of fungal mycelia is still in its early stages. For example, complex circuit boards will be made from smoother mycelial skin in the future, and further research is also needed to keep the metabolic activity and, thus, the living robot skin alive in the long term.
But mushroom mycelium is also being used for research beyond electronics and robotics, for example, for sustainable insulation and building materials or for a durable leather alternative.
A bot with wheels moves along the surface. A star-shaped soft-bodied robot flexes its five legs, shifting with an unsteady shuffle.
While these basic robotic creations are powered by conventional electricity from a plug or battery, what makes these robots unique is that they are operated by a living organism: a king oyster mushroom.
A team of researchers from Cornell University has modified two types of robots by integrating the mushroom’s mycelium, or rootlike threads, into the hardware, enabling the robots to sense and respond to the environment by utilizing the fungus’s electrical signals and its sensitivity to light.
These robots represent the latest achievement in the field of biohybrid robotics, where scientists endeavor to combine biological, living materials such as plant and animal cells or insects with synthetic components to create entities that are partly living and partly engineered.
While biohybrid robots have not yet moved beyond the laboratory, researchers aspire to see robot jellyfish exploring the oceans, sperm-powered bots delivering fertility treatments, and cyborg cockroaches searching for survivors in the aftermath of an earthquake.
Robert Shepherd, a senior author of a study detailing the robots published in the journal Science Robotics on August 28, stated, “Mechanisms such as computing, understanding, and responsive action are accomplished in the biological world and in the artificial world created by humans, and most of the time, biology performs these tasks better than our artificial systems.”
“Biohybridization is an effort to identify components in the biological world that we can leverage, comprehend, and control to enhance the functionality of our artificial systems,” added Shepherd, who is a professor of mechanical and aerospace engineering at Cornell University and leads the institution’s Organic Robotics Lab.
The team initiated the process by cultivating king oyster mushrooms (Pleurotus eryngii) in the lab using a basic kit purchased online. The selection of this mushroom species was based on its ease and quickness of growth.
They grew the mushroom’s threadlike networks or mycelium, which, according to the study, can sense, communicate, and transport nutrients, functioning somewhat like neurons in a brain. (However, it is not entirely accurate to refer to the creations as “shroom bots.” The mushroom is the fruit of the fungi, while the robots are energized by the rootlike mycelium.)
The cultivation of the fungus in a petri dish took between 14 and 33 days to fully integrate with the robot’s framework, as per new research led by scientists at Cornell University.
Mycelium produces minor electrical signals and can be linked to electrodes.
Andrew Adamatzky, a professor of unconventional computing at the University of the West of England in Bristol who develops fungal computers, stated that it remains unclear how fungi generate electrical signals.
“No one knows for sure,” mentioned Adamatzky, who was not involved in the research but reviewed it before publication.
“Essentially, all living cells produce action-potential-like spikes, and fungi are no exception.”
The research team encountered difficulties in engineering a system capable of detecting and utilizing the small electrical signals from the mycelia to control the robot.
Anand Mishra, a postdoctoral research associate in Cornell’s Organic Robotics Lab and the lead author of the study, mentioned, “You have to ensure that your electrode makes contact in the correct position because the mycelia are very thin. There isn’t much biomass there. After that, you cultivate them, and as the mycelia start growing, they wrap around the electrode.”
Mishra developed an electrical interface that effectively captures the mycelia’s primary electrical activity, processes it, and converts it into digital information that can activate the robot’s actuators or moving components.
The robots were able to walk and roll in response to the electrical spikes produced by the mycelia, and when Mishra and his colleagues exposed the robots to ultraviolet light, they altered their movement and trajectory, demonstrating their ability to react to their surroundings.
“Mushrooms are not particularly fond of light,” Shepherd remarked. “Based on the variations in light intensities, you can elicit different functions from the robot. It will move more swiftly or distance itself from the light.”
“Exciting” progress
Victoria Webster-Wood, an associate professor at Carnegie Mellon University’s Biohybrid and Organic Robotics Group in Pittsburgh, mentioned the excitement surrounding further developments in biohybrid robotics beyond the utilization of human, animal, and insect tissues.
“Fungi may offer advantages over other biohybrid approaches in terms of the conditions required to sustain them,” Webster-Wood, who was not involved in the research, noted.
“If they are more resilient to environmental conditions, this could render them an exceptional candidate for applications in agriculture and marine monitoring or exploration.”
The study highlighted that fungi can be mass-cultivated and thrive in various environmental conditions.
The rolling robot was operated by the researchers without a tether connecting it to the electrical hardware — a notable accomplishment according to Webster-Wood.
Webster-Wood, via email, mentioned that truly tether-free biohybrid robots are a challenge in the field and it’s quite exciting to see them achieve this with the mycelium system.
Regarding real-world applications, Shepherd stated that fungi-controlled technology could be useful in agriculture.
Shepherd mentioned that in this case, light was used as the input, but in the future, it will be chemical. The potential for future robots could be to sense soil chemistry in row crops and decide when to add more fertilizer. This might help mitigate downstream effects of agriculture like harmful algal blooms, according to Shepherd.
Adamatzky emphasized the huge potential of fungi-controlled robots and fungal computing, mentioning that more than 30 sensing and computing devices using live fungi were produced in his lab. This included growing a self-healing skin for robots that can react to light and touch.
Adamatzky, via email, explained that when an adequate drivetrain is provided, the robot can, for example, monitor the health of ecological systems. The fungal controller would react to changes, such as air pollution, and guide the robot accordingly.
Mestre, who works on the social, ethical, and policy implications of emergent technologies, mentioned that if biohybrid robots become more sophisticated and are deployed in the ocean or another ecosystem, it could disrupt the habitat, challenging the traditional distinction between life and machine.
Mestre stated that if these robots are released in big numbers, it could be disruptive to the ecosystem. He also emphasized the importance of considering the ethical concerns as this research continues to develop.
Mushrooms have gained popularity as a vegan substitute for leather and are being used in high-end fashion and even in car manufacturing. Additionally, hallucinogenic varieties of mushrooms have been found to alleviate treatment-resistant depression.
Researchers at Johannes Kepler University in Linz, Austria, have found a significant use for fungi that could potentially help mitigate global warming.
The team, led by scientist Martin Kaltenbrunner, devised a way to use fungi as a biodegradable base material for electronics chips, as outlined in the journal Science Advances.
Kaltenbrunner, with a focus on sustainability, material science, and engineering, explored using sustainable materials in robotics in previous research.
In their latest research, the team looked at redesigning the substrate of electronic circuits utilizing a mushroom-based material to replace unrecyclable plastic polymers.
This mushroom, Ganoderma lucidum, was used for the experiment and has a history of promoting health and longevity in Asia. The team was particularly interested in the skin generated by this mushroom to cover its root-like appendage, called a mycelium.
When the skin was dried out and tested, it was discovered that it could endure temperatures of 200°C (390°F), and it acted as a good insulator and conductor. The skin could also easily hold circuit boards after being treated with metal and strengthened by the addition of copper, chromium, and gold.
Another positive characteristic of this remarkable fungi is its thickness, which is comparable to that of paper. Paper was considered as a potential substrate, but it was rejected due to its highly water-intensive and toxic chemical-soaked production process.
In contrast, the mushroom substrate could be bent up to 2,000 times without any damage and was so adaptable in shape that it surpassed the planar geometry challenges faced by engineers in chip design.
Andrew Adamatzky, a professor in unconventional computing at the University of the West of England, stated, “The prototypes produced are impressive and the results are groundbreaking,” in New Scientist.
Kaltenbrunner and his team anticipate that the mushroom-encased chip will be suitable for use in wearable, low-powered, and short-lived Bluetooth sensors for humidity and proximity, as well as in radio tags.
Moreover, the mycelium’s ability to repel moisture and UV light indicates that it could potentially endure for several hundred years. The research team has also proposed a completely new concept of batteries, having successfully used the mushroom skins as battery separators and casings.
Even more encouraging, the production of these mushrooms has minimal impact on the environment — in fact, the more CO2 available for their production, the better. The team effortlessly grew and harvested mature mycelium on beechwood in just four weeks.
Furthermore, when these devices reach the end of their lifespan, they can biodegrade quietly in any soil and disappear in less than two weeks, presenting the kind of solution that engineers need to adopt in order to counter the unsustainable electronic consumption threatening the world.
Introduction
In a world affected by climate change and extensive waste production, environmental impact must be a primary consideration in technological innovations. Disposable technology, in particular, represents an increasingly large portion of our waste, accumulating over 100,000 tons per day. End-of-life consumer electronics, which are often difficult to recycle due to diverse product designs and material compositions, are typically discarded since they are cheaply produced. In addition, the unsustainable use of rare and often toxic materials poses an environmental threat when inadequately treated or landfilled.
Designs for easily recyclable devices, the use of low-cost and renewable materials, and the implementation of biodegradable or transient systems are promising approaches toward technologies with a closed life cycle, opening up new opportunities in various fields from medicine and environmental monitoring to security and intelligence applications.
Recent advancements in robotics focusing on safe human-machine interaction, swarm robotics, and untethered autonomous operation are frequently inspired by the diversity found in nature. The intricacy observed in nature motivates scientists from various disciplines to develop soft and lightweight forms of robots that aim to replicate or mimic the graceful movements of animals or their efficient energy management.
In the future, the increased integration of such soft robots into our daily lives poses, akin to consumer electronics, environmental concerns at the end of their life cycle. Once again, we can derive inspiration from nature and design our creations in a sustainable manner, mitigating the issues associated with current technology. Unlike standardized industrial robots, which are already incorporated into recycling loops, bioinspired robotics will find diverse ecological applications in various niches.
Examples range from soft healthcare machines that assist elderly individuals in their daily activities to robots that harvest produce and then decompose as compost for the next season’s plants. Ongoing demonstrations of transient behavior include elastic pneumatic actuators, in vivo-operating millibots for wound patching, robot swarms for drug delivery, and small grippers controlled by engineered muscle tissues.
These developments benefit from extensive research efforts towards bioresorbable electronic devices, primarily explored in the biomedical sector, and sustainable energy storage technology, aiming to address environmental concerns associated with the growing demand for energy in mobile devices. The future challenge for autonomous robots will be the efficient integration of actuators, sensors, computation, and energy into a single robot, requiring novel concepts and eco-friendly solutions. Success can only be achieved by bringing together material scientists, chemists, engineers, biologists, computer scientists, and roboticists.
Here, we present materials, manufacturing methods, and design strategies for eco-friendly bioinspired robots and their components. Our focus is on sustainable device concepts, non-toxic, and low-cost production processes, and environmentally safe materials that are either biodegradable or sourced from renewable resources, all of which address the current pressing needs. The review begins with an exploration of sustainability and summarizes various approaches that enable technology with reduced environmental impact.
Turning our attention to soft and lightweight forms of robotics, we then compare biodegradable polymers—from elastomers to bioplastics—and regenerative resources for the primary robotic body. In each component of typical autonomous robots, we examine environmentally friendly sensors, computation, and control tools, and introduce promising options for energy harvesters and storage systems, including solar- and biofuel cells, as well as batteries. Lastly, we showcase a selection of current soft robotic demonstrations that utilize economical material approaches and degrade with a positive impact on the surroundings.
Sustainable Approaches for Soft Robotics
The main scientific inquiries into sustainable materials development for robotics revolve around two questions. First, can we use new materials and resources that contribute to a more sustainable future? Second, how can we utilize or modify existing materials to reduce their ecological footprint on the environment?
Addressing the first question involves the development of high-performance materials with increased durability, materials sourced from renewable sources, or biodegradable ones, all aiming to conserve valuable resources or minimize waste. Similar objectives apply to solutions addressing the second question, which focus on fabrication processes, recycling, and product designs. Sustainability in robotics encompasses numerous facets, approaches, and solutions, which we delve into in this section, including renewable resources, recycling, and biodegradability.
Renewable Resources
Unlike finite resources such as fossil fuels, nuclear fuels, and rare earth metals, renewable materials are either perpetually available or naturally replenished within reasonable timeframes. In an ideal sustainable scenario, the consumption rates of material/energy equal the regeneration rate of the resources. Autonomous robotics stand to benefit from renewable resources more than other technologies, by harnessing energy from solar power or tidal waves and by replacing damaged body parts with spare parts that naturally regenerate.
Solar power, a long-standing standard for space exploration robots, offers an inexhaustible energy supply that can be stored in a robot’s battery to provide consistent power over an extended period. The smaller and lighter a robot is, the more efficient it becomes to utilize solar power over fuel energy, as robots only need to carry collectors, not the fuel itself. For instance, extremely lightweight solar panels can deliver substantial power (23 W g−1) without adding considerable weight to the robot.
Rather than using fossil-based plastics, the robotic body can be constructed from plant-based materials. Green composite materials show promise as suitable candidates for sturdy yet lightweight components, not only for robots but also for mobile machinery in general. In the context of electric cars, lightweight natural fiber composites with adequate mechanical properties could replace dense synthetic materials for both interior and exterior components, helping to offset the increasing weight of batteries.
To cater to the growing interaction between machines and humans, elastomers derived from biomaterials can be used to create soft grippers or (robotic) soft electronic skins (e-skins) that mimic biological designs. Carbonized biomass can be employed as an electron conductive alternative to metals in many electronic components, or it can participate in the electrochemical reactions of batteries and supercapacitors.
However, the use of renewable materials primarily addresses resource issues rather than waste issues. For instance, vulcanized natural rubber, despite being naturally derived, does not degrade within a reasonable timeframe and necessitates waste treatment and recycling. Therefore, renewability, biodegradability, and recycling must be collectively optimized to yield a sustainable technology with a beneficial impact on resources and waste.
Recycling
For technologies that must meet high performance benchmarks—such as complementary metal-oxide-semiconductor (CMOS) chips or Bluetooth communication—finding renewable or biodegradable alternatives remains challenging. Thus, recycling emerges as a viable approach toward the more sustainable use of technology. It is important to view recycling as the process of transforming waste into a valuable (similar) product. Recycling also encompasses the generation of energy through waste combustion, although this is only sustainable to a certain extent, as it consumes resources and elevates CO2 emissions.
In general, whether it’s material, device, or robot recycling, the decision is often driven by economic considerations: a product is more likely to be recycled if the cost of recycling is lower than the cost of manufacturing a new one.
As a result, an effective recycling process must be economically viable, easily achievable technologically, integrated into closed production-recycling loops, focused on valuable materials, and requiring minimal energy. An example of efficient recycling is lead-acid batteries (such as car batteries). Due to their standardized simple design, these batteries can be easily taken apart and recycled. When technicians replace the batteries, they close the life-cycle loop by sending the worn-out batteries back to the manufacturers.
Recycling other electronic waste (e-waste) is often challenging and not easily achievable due to the varying architecture and material composition of integrated circuits, Li-batteries, or displays. To reduce recycling costs, e-waste is sometimes sent to developing countries like Ghana, where improper e-waste processing endangers workers and residents.
To make robotics sustainable, recycling must be considered during the design phase. A successful recycling plan necessitates the easy separability of individual robotic materials to facilitate straightforward reuse, exchange, and upgrading of robots. While this is more feasible for traditional robots, as they often consist of standardized electronic parts and actuators, it can be difficult for soft robots, which employ various actuation principles and materials. However, soft robots benefit from less complex material arrangements.
For instance, pneumatically driven soft robots have combined actuators and bodies. As a result, the complexity of recycling an entire robotic body with many actuators (comprised of various components themselves) is reduced to recycling a single material.
Similarly, the less stringent requirements of control feedback allow for e-skins with reduced material complexity. A beneficial approach is to incorporate self-healing materials or concepts for soft robots that autonomously restore materials functionality. Tan and colleagues developed a stretchable optoelectronic material for stretchable electronics and soft robotics with light emission and feedback sensing, which independently self-heals after being punctured.
Another sustainable approach involves using fewer materials in the design. Autonomous robots benefit twofold from lightweight materials/component designs, aiming to first reduce weight and increase operation time, and second minimize environmental impact by decreasing the total amount of waste. Ultimately, zero waste robotics could be achieved with fully biodegradable materials.
Biodegradable materials are a promising material class for sustainable technology. In the ideal scenario, a material breaks down into smaller, environmentally friendly components that are metabolized by bacteria or enzymes at timescales comparable to typical waste processing. Moreover, the degradation process should start at the end-of-life phase of a device, triggered and occurring at a controlled rate and under feasible environmental conditions. The concept of biodegradability is not clearly defined and handled consistently in the literature, particularly concerning multicomponent/material devices.
For biodegradable electronics, not all components may be biodegradable, or they may degrade at different rates. Bao and colleagues distinguish between materials with transient behavior (type I) that disintegrate into sufficiently small components and biodegradable materials (type II) that undergo complete chemical degradation into tiny molecules.
Transient electronics, made from type I materials, play a significant role in the biomedical sector. Implantable or ingestible devices are designed to remain in our bodies, monitoring cardiac pressure, glucose levels, or neural activities. The degradation of these devices must be achievable under physiological conditions to create truly bioresorbable devices. Therefore, the lifetime of all materials should be limited to timescales comparable to the healing of human tissue or regeneration processes, and each degradation product must be noncytotoxic.
Such material design also holds promise for microbots operating inside the body, for wound treatment or drug delivery applications. Outside the body, biodegradable materials enable secure systems that disappear after their operation, preventing plagiarism, espionage, or unauthorized acquisition of critical technology.
Biodegradable robotics and electronics (type II) require the complete metabolization of all constituents. It is not enough for materials to break down into smaller units; they must be converted into biomass or gases by microorganisms. Additionally, materials that degrade into bio-derived small molecules offer intrinsic biocompatibility and recyclability, returning energy back to nature. This technology may ultimately provide solutions to critical e-waste issues while transforming conventional robotics into creative solutions that encompass the entire technology life cycle.
To ensure the correct degradation of materials, it is crucial to accurately report the application areas, operational environments, and degradation timescales for type I or II technology. Implanted devices should degrade under conditions similar to our body’s environment, produce harvesting robots must decompose in organic waste and compost, while maritime fish robots need materials that disintegrate in seawater.
Immersing a material into an unsuitable environment might not result in any degradation, even if it is labeled biodegradable. This misunderstanding is unfortunately common in reports of biodegradable materials, as illustrated by Bagheri and colleagues.
For their study on degradation, Bagheri and co-workers immersed typical biodegradable polymers like polylactic acid (PLA), polycaprolactone (PCL), and poly(3-hydroxybutyrate) (P3HB) in seawater. Surprisingly, they discovered that these polymers hardly degrade over 400 days, with a mass loss of less than 10%. The same holds true for the elastomer Ecoflex used in the soft robotics community. Although this polymer is 100% fossil-based, it fully decomposes in approximately 80 days under industrial composting conditions.
Cellulose, for instance, requires about 50 days under the same conditions. In seawater, factors such as temperature, microorganisms, and oxygen availability differ significantly from those in compost, leading to a much longer degradation time for Ecoflex.
While there are also standards for biodegradation in seawater, the most common standards that certify biodegradable polymers, particularly in packaging, target degradation in industrial composting facilities. The ISO 17088 norm, effective since 2008, is the globally applicable standard based on the European EN13432 and American ASTM 6400-04 standards. In essence, biodegradation tests monitor the CO2 evolution of polymer/compost mixtures under optimum humidity and oxygen conditions at 58 °C, with specified pass levels.
In situations where industrial composting is not feasible, biodegradable materials are necessary to disintegrate in less controlled environments. For instance, tech waste disposed of through household composts or in nature needs to vanish under milder conditions, yet at equally rapid rates.
For biodegradable materials used in electronics or robotics, additional declarations should indicate that the robot, once its purpose is fulfilled and it reaches the end of its life cycle, can simply be discarded without consideration for environmental conditions or be left at the disposal site. Therefore , advancing materials that enable individual-based waste management requires research, standards, and specifications.
A wheeled robot traverses the ground. A soft-bodied robotic star shifts its five legs, moving in a somewhat clumsy manner.
These basic robotic creations would be considered ordinary if not for one distinguishing feature: they are controlled by a living organism—a king oyster mushroom.
By integrating the mushroom’s mycelium, or rootlike filaments, into the robot’s design, researchers from Cornell University have created two types of robots that perceive and react to their surroundings by utilizing electrical signals generated by the fungus and its light sensitivity.
These robots represent the latest achievement in the field of biohybrid robotics, where scientists aim to merge biological materials, such as plant and animal cells or insects, with artificial components to create entities that are partially alive and partially engineered.
Although biohybrid robots have not yet left the laboratory, researchers are optimistic that future applications could include robot jellyfish exploring the oceans, sperm-driven robots delivering fertility treatments, and cyborg cockroaches searching for survivors after earthquakes.
“Biological mechanisms, including computing, comprehension, and actions in response, exist in nature, often outperforming the artificial systems developed by humans,” stated Robert Shepherd, a senior author of a study about the robots published on August 28 in the journal Science Robotics.
“Biohybridization endeavors to identify biological components that we can utilize, comprehend, and control to enhance the performance of our artificial systems,” added Shepherd, a professor of mechanical and aerospace engineering at Cornell University and head of the school’s Organic Robotics Lab.
A combination of fungus and machinery
The research team began by cultivating king oyster mushrooms (Pleurotus eryngii) in the lab using a basic kit purchased online. They selected this mushroom species because it is simple and quick to grow.
They grew the mushroom’s threadlike structures, or mycelium, which can develop networks capable of sensing, communicating, and transporting nutrients—similar in function to neurons in a brain. (It’s important to note that referring to these as shroom bots isn’t entirely correct, as the robots derive their power from the rootlike mycelium, not the mushroom itself.)
Mycelium emits small electrical signals and can be linked to electrodes.
Andrew Adamatzky, a professor specializing in unconventional computing at the University of the West of England in Bristol who constructs fungal computers, stated that the exact mechanism by which fungi generate electrical signals remains uncertain.
“Currently, nobody knows for certain,” said Adamatzky, who did not participate in the study but reviewed it prior to publication.
“Basically, all living cells generate action-potential-like spikes, and fungi are no different.”
The research team encountered difficulties in creating a system that could identify and utilize the faint electrical signals from the mycelia to control the robot.
“It’s essential to ensure that your electrode is positioned correctly because the mycelia are extremely fine. There is minimal biomass present,” explained lead author Anand Mishra, a postdoctoral research associate in Cornell’s Organic Robotics Lab. “Afterward, you culture them, and as the mycelia begin to grow, they wrap around the electrode.”
Mishra developed an electrical interface that effectively reads the mycelia’s raw electrical activity, processes it, and converts it into digital signals capable of activating the robot’s actuators or moving parts.
The robots demonstrated the ability to walk and roll in response to electrical spikes generated by the mycelia, and when stimulated with ultraviolet light, they altered their gait and trajectory, indicating that they could react to their environment.
“Mushrooms tend to shy away from light,” Shepherd remarked. “By varying light intensities, you can induce different functions in the robot. It might move faster or steer away from the light.”
‘Exciting’ progress
The advancements in biohybrid robotics that extend beyond human, animal, and insect tissues are exhilarating, noted Victoria Webster-Wood, an associate professor at Carnegie Mellon University’s Biohybrid and Organic Robotics Group in Pittsburgh.
“Fungi may offer advantages over other biohybrid strategies regarding the environmental conditions needed for their survival,” stated Webster-Wood, who was not part of the research.
“If they can withstand environmental variations, it could make them an excellent choice for biohybrid robots used in agriculture, marine monitoring, or exploratory purposes.”
The research highlighted that fungi can be grown in significant volumes and can prosper in a variety of environments.
The team operated the rolling robot without a tether linking it to the electrical components — a task that Webster-Wood emphasized as particularly significant.
“Completely tetherless biohybrid robots pose a challenge in this field,” she mentioned in an email, “and witnessing their accomplishment with the mycelium system is extremely thrilling.”
Fungi-managed technology could find uses in agriculture, as noted by Shepherd.
“In this scenario, we utilized light as the stimulus, but in the future, it will likely be chemical. The future possibilities for robots might include detecting soil chemistry in crop rows and determining when to apply additional fertilizer, potentially alleviating the negative downstream impacts of agriculture such as harmful algal blooms,” he explained to the Cornell Chronicle.
According to Adamatzky, fungi-controlled robots, and fungal computing in a broader sense, hold significant promise.
He stated that his laboratory has developed over 30 devices for sensing and computing using live fungi, including creating a self-repairing skin for robots that can respond to both light and touch.
“With a suitable drivetrain (transmission system) in place, the robot could, for instance, assess the condition of ecological systems. The fungal controller would respond to variations like air pollution and direct the robot accordingly,” Adamatzky wrote in an email.
“The emergence of yet another fungal device — a robotic controller — excitingly showcases the extraordinary potential of fungi.”
Rafael Mestre, a lecturer at the University of Southampton’s School of Electronics and Computer Science in the UK, who focuses on the social, ethical, and policy implications of emerging technologies, expressed that if biohybrid robots become increasingly advanced and are introduced into oceanic or other ecosystems, it could disrupt the environment, challenging the conventional boundaries between living organisms and machines.
“You are introducing these entities into the food web of an ecosystem where they may not belong,” Mestre remarked, who was not part of the recent study. “If they are released in significant quantities, it could be disruptive. At this time, I don’t perceive strong ethical concerns surrounding this specific research… but as it continues to evolve, it is essential to contemplate the consequences of releasing this into the wild.”
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