On the left, a Hermès bag made using fine mycelium as a leather alternative, made in partnership with the biotech company MycoWorks; on right, a sheet of mycelium "leather."
A natural material that looks and feels like real leather is taking the fashion world by storm. Scientists view mycelium—the vegetative part of a mushroom-producing fungus—as a planet-friendly alternative to animal hides and plastics.
Products crafted from this vegan leather are emerging, with others poised to hit the market soon. Among them are the Hermès Victoria bag, Lululemon's yoga accessories, Adidas' Stan Smith Mylo sneaker, and a Stella McCartney apparel collection.
The Adidas' Stan Smith Mylo concept sneaker, made in partnership with Bolt Threads, uses an alternative leather grown from mycelium; a commercial version is expected in the near future.
Adidas
Hermès has held presales on the new bag, says Philip Ross, co-founder and chief technology officer of MycoWorks, a San Francisco Bay area firm whose materials constituted the design. By year-end, Ross expects several more clients to debut mycelium-based merchandise. With "comparable qualities to luxury leather," mycelium can be molded to engineer "all the different verticals within fashion," he says, particularly footwear and accessories.
More than a half-dozen trailblazers are fine-tuning mycelium to create next-generation leather materials, according to the Material Innovation Initiative, a nonprofit advocating for animal-free materials in the fashion, automotive, and home-goods industries. These high-performance products can supersede items derived from leather, silk, down, fur, wool, and exotic skins, says A. Sydney Gladman, the institute's chief scientific officer.
That's only the beginning of mycelium's untapped prowess. "We expect to see an uptick in commercial leather alternative applications for mycelium-based materials as companies refine their R&D [research and development] and scale up," Gladman says, adding that "technological innovation and untapped natural materials have the potential to transform the materials industry and solve the enormous environmental challenges it faces."
In fewer than 10 days in indoor agricultural farms, "we grow large slabs of mycelium that are many feet wide and long. We are not confined to the shape or geometry of an animal."
Reducing our carbon footprint becomes possible because mycelium can flourish in indoor farms, using agricultural waste as feedstock and emitting inherently low greenhouse gas emissions. Carbon dioxide is the primary greenhouse gas. "We often think that when plant tissues like wood rot, that they go from something to nothing," says Jonathan Schilling, professor of plant and microbial biology at the University of Minnesota and a member of MycoWorks' Scientific Advisory Board.
But that assumption doesn't hold true for all carbon in plant tissues. When the fungi dominating the decomposition of plants fulfill their function, they transform a large portion of carbon into fungal biomass, Schilling says. That, in turn, ends up in the soil, with mycelium forming a network underneath that traps the carbon.
Unlike the large amounts of fossil fuels needed to produce styrofoam, leather and plastic, less fuel-intensive processing is involved in creating similar materials with a fungal organism. While some fungi consist of a single cell, others are multicellular and develop as very fine threadlike structures. A mass of them collectively forms a "mycelium" that can be either loose and low density or tightly packed and high density. "When these fungi grow at extremely high density," Schilling explains, "they can take on the feel of a solid material such as styrofoam, leather or even plastic."
Tunable and supple in the cultivation process, mycelium is also reliably sturdy in composition. "We believe that mycelium has some unique attributes that differentiate it from plastic-based and animal-derived products," says Gavin McIntyre, who co-founded Ecovative Design, an upstate New York-based biomaterials company, in 2007 with the goal of displacing some environmentally burdensome materials and making "a meaningful impact on our planet."
After inventing a type of mushroom-based packaging for all sorts of goods, in 2013 the firm ventured into manufacturing mycelium that can be adapted for textiles, he says, because mushrooms are "nature's recycling system."
The company aims for its material—which is "so tough and tenacious" that it doesn't require any plastic add-on as reinforcement—to be generally accessible from a pricing standpoint and not confined to a luxury space. The cost, McIntyre says, would approach that of bovine leather, not the more upscale varieties of lamb and goat skins.
Already, production has taken off by leaps and bounds. In fewer than 10 days in indoor agricultural farms, "we grow large slabs of mycelium that are many feet wide and long," he says. "We are not confined to the shape or geometry of an animal," so there's a much lower scrap rate.
Decreasing the scrap rate is a major selling point. "Our customers can order the pieces to the way that they want them, and there is almost no waste in the processing," explains Ross of MycoWorks. "We can make ours thinner or thicker," depending on a client's specific needs. Growing materials locally also results in a reduction in transportation, shipping, and other supply chain costs, he says.
Yet another advantage to making things out of mycelium is its biodegradability at the end of an item's lifecycle. When a pair of old sneakers lands in a compost pile or landfill, it decomposes thanks to microbial processes that, once again, involve fungi. "It is cool to think that the same organism used to create a product can also be what recycles it, perhaps building something else useful in the same act," says biologist Schilling. That amounts to "more than a nice business model—it is a window into how sustainability works in nature."
A product can be called "sustainable" if it's biodegradable, leaves a minimal carbon footprint during production, and is also profitable, says Preeti Arya, an assistant professor at the Fashion Institute of Technology in New York City and faculty adviser to a student club of the American Association of Textile Chemists and Colorists.
On the opposite end of the spectrum, products composed of petroleum-based polymers don't biodegrade—they break down into smaller pieces or even particles. These remnants pollute landfills, oceans, and rivers, contaminating edible fish and eventually contributing to the growth of benign and cancerous tumors in humans, Arya says.
Commending the steps a few designers have taken toward bringing more environmentally conscious merchandise to consumers, she says, "I'm glad that they took the initiative because others also will try to be part of this competition toward sustainability." And consumers will take notice. "The more people become aware, the more these brands will start acting on it."
A further shift toward mycelium-based products has the capability to reap tremendous environmental dividends, says Drew Endy, associate chair of bioengineering at Stanford University and president of the BioBricks Foundation, which focuses on biotechnology in the public interest.
The continued development of "leather surrogates on a scaled and sustainable basis will provide the greatest benefit to the greatest number of people, in perpetuity," Endy says. "Transitioning the production of leather goods from a process that involves the industrial-scale slaughter of vertebrate mammals to a process that instead uses renewable fungal-based manufacturing will be more just."
New research focuses on methods that could change medicine-making worldwide. The scientists propose bursting cells open, removing their DNA and using the cellular gears inside to make therapies.
Rao and his team of collaborators, which spans multiple research institutions, believe they have a better approach that may change medicine-making worldwide. They suggest forgoing the concept of using living cells as medicine-producers. Instead, they propose breaking the cells and using the remaining cellular gears for assembling the therapeutic compounds. Instead of inserting the DNA into living cells, the team burst them open, and removed their DNA altogether. Yet, the residual molecular machinery of ribosomes, polymerases and other cogwheels still functioned the way it would in a cell. “Now if you drop your DNA drug-making instructions into that soup, this machinery starts making what you need,” Rao explains. “And because you're no longer worrying about living cells, it becomes much simpler and more efficient.” The collaborators detail their cell-free protein synthesis or CFPS method in their recent paper published in preprint BioAxiv.
While CFPS does not use living cells, it still needs the basic building blocks to assemble proteins from—such as amino acids, nucleotides and certain types of enzymes. These are regularly added into this “soup” to keep the molecular factory chugging. “We just mix everything in as a batch and we let it integrate,” says James Robert Swartz, professor of chemical engineering and bioengineering at Stanford University and co-author of the paper. “And we make sure that we provide enough oxygen.” Rao likens the process to making milk from milk powder.
For a variety of reasons—from the field’s general inertia to regulatory approval hurdles—the method hasn’t become mainstream. The pandemic rekindled interest in medicines that can be made quickly and easily, so it drew more attention to the technology.
The idea of a cell-free protein synthesis is older than one might think. Swartz first experimented with it around 1997, when he was a chemical engineer at Genentech. While working on engineering bacteria to make pharmaceuticals, he discovered that there was a limit to what E. coli cells, the workhorse darling of pharma, could do. For example, it couldn’t grow and properly fold some complex proteins. “We tried many genetic engineering approaches, many fermentation, development, and environmental control approaches,” Swartz recalls—to no avail.
“The organism had its own agenda,” he quips. “And because everything was happening within the organism, we just couldn't really change those conditions very easily. Some of them we couldn’t change at all—we didn’t have control.”
It was out of frustration with the defiant bacteria that a new idea took hold. Could the cells be opened instead, so that the protein-forming reactions could be influenced more easily? “Obviously, we’d lose the ability for them to reproduce,” Swartz says. But that also meant that they no longer needed to keep the cells alive and could focus on making the specific reactions happen. “We could take the catalysts, the enzymes, and the more complex catalysts and activate them, make them work together, much as they would in a living cell, but the way we wanted.”
In 1998, Swartz joined Stanford, and began perfecting the biochemistry of the cell-free method, identifying the reactions he wanted to foster and stopping those he didn’t want. He managed to make the idea work, but for a variety of reasons—from the field’s general inertia to regulatory approval hurdles—the method hasn’t become mainstream. The pandemic rekindled interest in medicines that can be made quickly and easily, so it drew more attention to the technology. For their BioArxiv paper, the team tested the method by growing a specific antiviral protein called griffithsin.
First identified by Barry O’Keefe at National Cancer Institute over a decade ago, griffithsin is an antiviral known to interfere with many viruses’ ability to enter cells—including HIV, SARS, SARS-CoV-2, MERS and others. Originally isolated from the red algae Griffithsia, it works differently from antibodies and antibody cocktails.
Most antiviral medicines tend to target the specific receptors that viruses use to gain entry to the cells they infect. For example, SARS-CoV-2 uses the infamous spike protein to latch onto the ACE2 receptor of mammalian cells. The antibodies or other antiviral molecules stick to the spike protein, shutting off its ability to cling onto the ACE2 receptors. Unfortunately, the spike proteins mutate very often, so the medicines lose their potency. On the contrary, griffithsin has the ability to cling to the different parts of viral shells called capsids—namely to the molecules of mannose, a type of sugar. That extra stuff, glued all around the capsid like dead weight, makes it impossible for the virus to squeeze into the cell.
“Every time we have a vaccine or an antibody against a specific SARS-CoV-2 strain, that strain then mutates and so you lose efficacy,” Rao explains. “But griffithsin molecules glom onto the viral capsid, so the capsid essentially becomes a sticky mess and can’t enter the cell.” Mannose molecules also don’t mutate as easily as viruses’ receptors, so griffithsin-based antivirals do not have to be constantly updated. And because mannose molecules are found on many viruses’ capsids, it makes griffithsin “a universal neutralizer,” Rao explains.
“When griffithsin was discovered, we recognized that it held a lot of promise as a potential antiviral agent,” O’Keefe says. In 2010, he published a paper about griffithsin efficacy in neutralizing viruses of the corona family—after the first SARS outbreak in the early 2000s, the scientific community was interested in such antivirals. Yet, griffithsin is still not available as an off-the-shelf product. So during the Covid pandemic, the team experimented with synthesizing griffithsin using the cell-free production method. They were able to generate potent griffithsin in less than 24 hours without having to grow living cells.
The antiviral protein isn't the only type of medicine that can be made cell-free. The proteins needed for vaccine production could also be made the same way. “Such portable, on-demand drug manufacturing platforms can produce antiviral proteins within hours, making them ideal for combating future pandemics,” Rao says. “We would be able to stop the pandemic before it spreads.”
Top: Describes the process used in the study. Bottom: Describes how the new medicines and vaccines could be made at the site of a future viral outbreak.
Image courtesy of Rao and team, sourced from An approach to rapid distributed manufacturing of broad spectrumanti-viral griffithsin using cell-free systems to mitigate pandemics.
Rao’s idea is to perfect the technology to the point that any hospital or pharmacy can load up the media containing molecular factories, mix up the required amino acids, nucleotides and enzymes, and harvest the meds within hours. That will allow making medicines onsite and on demand. “That would be a self-contained production unit, so that you could just ship the production wherever the pandemic is breaking out,” says Swartz.
These units and the meds they produce, will, of course, have to undergo rigorous testing. “The biggest hurdles will be validating these against conventional technology,” Rao says. The biotech industry is risk-averse and prefers the familiar methods. But if this approach works, it may go beyond emergency situations and revolutionize the medicine-making paradigm even outside hospitals and pharmacies. Rao hopes that someday the method might become so mainstream that people may be able to buy and operate such reactors at home. “You can imagine a diabetic patient making insulin that way, or some other drugs,” Rao says. It would work not unlike making baby formula from the mere white powder. Just add water—and some oxygen, too.
In the U.S. and Europe, it is illegal to reuse pacemakers and other implants. Therefore, cardiologists export them to the global South where they save the lives of people of all ages.
Often he observed there were no doctors in the E.R.s, and hte nurses could render only basic first aid. “When somebody fell into a coma, they fell into a coma,“ Israel remembers. “There weren’t even any defibrillators to restart a patient’s heart,” while defibrillators are standard equipment in most clinics in the U.S. and Europe as lifesaving devices. When Israel finally visited the largest and most modern hospital in Nairobi, he found it better equipped but he learned that its services were only available to patients who could afford them. The cardiologist there had a drawer full of petitions from patients with heart ailments who couldn’t afford lifesaving surgery. Even two decades ago, a pacemaker cost $5,000 in Kenya, which made it unaffordable for most Kenyans who earn an average of $600 per month.
Since 2003, Israel and a team of two doctors and two nurses visit Kenya and Zambia once or twice a year to implant German pacemakers for free. Notably, the pacemakers and defibrillators Israel exports to Africa would end up in the landfill in Germany. Clinics have to pay for specialized services to dispose of this medical equipment. “In Germany, I could go to jail if I used a defibrillator that is one day past its expiration date,“ Israel says, “but in Kenya, people don’t have the money for the cheapest model. What nonsense to throw this precious medical equipment away while people in poorer countries die because they desperately need it.“
Israel works at the breakpoint between the laws in a wealthy country like Germany and the reality in the global South. The U.S. and most European countries have strict laws that ban the reuse of medical implants and enforce strict expiration dates for medical equipment. “But if a pacemaker is a few days past its expiration date, it still works perfectly fine,“ Israel says. “And it also happens that we implant a pacemaker and five months later it turns out that the patient needs a different kind. Then we replace it and we’d have to trash the first one in Germany, though it could easily run another 12 years.“
“If we get this right, we have lots of devices we can implant, hips and knees, etcetera. Where this will lead is limitless," says Eva Kline Rogers, the program coordinator for My Heart, Your Heart.
Israel has been collecting donations of pacemakers and defibrillators from manufacturers but also from other doctors and from funeral homes for his nonprofit Pacemakers for East Africa since 2003. Most funeral homes in the U.S. and Europe are legally obliged to remove pacemakers from the dead before cremation. “Most pacemakers survive their owners,“ says Israel. He sterilizes the pacemakers and finds them a new life in East Africa. Studies show that reused pacemakers carry no greater risk for the patients than new ones.
In the U.S., University of Michigan professor Thomas Crawford heads up a similar initiative, My Heart, Your Heart. “Each year 1 to 2 million individuals worldwide die due to a lack of access to pacemakers and defibrillators,” the organization notes on its website. The nonprofit was founded in 2009, but it took four years for the doctors to get permission from the FDA to export pacemakers. Since receiving permission, the organization has sent dozens of devices to the Philippines, Haiti, Venezuela, Kenya, Sierra Leone and Ukraine. “We were the first doctors ever to implant a pacemaker in Sierra Leone in 2018,” says Crawford, who has traveled extensively to most of the recipient countries.
Even individuals can donate their pacemakers; the organization offers a prepaid envelope. “My mother recently passed and she donated her device,” says Tina Alexandris-Souphis, one of the doctors at University of Michigan who collaborates on My Heart, Your Heart. The organization works with World Medical Relief and the U.K. based charity Pace4Life to maintain a registry of the most urgent patients and send devices to where they are needed the most.
My Heart, Your Heart is also conducting a randomized controlled trial to provide further evidence that reused pacemakers pose no additional risk. “Our vision is that we establish this is safe and create a blueprint for organizations around the world to safely reuse these devices instead of them being thrown in the trash,” says Eva Kline Rogers, the program’s coordinator. “If we get this right, we have lots of devices we can implant, hips and knees, etc. Where this will lead is limitless.” She points out that in addition to receiving the donated devices, the doctors in the global South also benefit from the expertise of renowned cardiologists, such as Crawford, who sometimes advise them in complex cases.
And Adrian Baranchuk, a Canadian doctor at the Kingston General Hospital at the Queen’s University, regularly travels through South America with his “cardiology van” to help villagers in remote areas with heart problems.
Israel says that he’s been accused of racism, in thinking that these pacemakers are suitable for those in the global South - many of whom are people of color - even though officials in wealthier countries consider them to be trash. The cardiologist counters such criticism with stories about desperate need of his patients. At his first medical visit to Nairobi that he organized with a local cardiologist, six patients were waiting for him. “In Germany, they would all be considered emergencies,” Israel says. One eighty-year old grandmother had a heartrate of 18. “I’ve never before seen anything like this,” Israel exclaims. “At first I thought I couldn’t find her pulse before I realized that her heart was only beating once every three seconds.” After the surgery, she got up, dressed herself and hurriedly packed her bag, explaining she had a ton of work to accomplish. Her family was in disbelief, Israel says. “They told me she had been bedridden for five years because as soon as she tried to get up she would faint.”
Israel has been accused of racism, in thinking that these pacemakers are suitable for those in the global South even though they're considered to be trash by officials in wealthier countries. The cardiologist counters such criticism with stories about desperate need of his patients.
Carsten Israel
The hospital in Nairobi where Israel conducts the surgeries, charges patients $200 for the use of its facilities. If patients can’t afford that sum, Israel will pay it from the funds of his nonprofit. For some people, $200 far exceeds their resources. Once, a family from the extremely poor Northern region of Kenya told him they couldn’t afford the $3 for the bus ride to Nairobi. Israel suspected this was a pretense because they were afraid of the surgery and agreed to reimburse the $3, “but when they came, they were wearing rags and were so rail-thin, I understood that they really needed every cent they had for food.”
Israel is a renowned cardiologists in Germany. And yet, he considers his work in East Africa to be particularly meaningful. “Generally, most patients in Germany will get the treatment they need,” he says, “and I never before experienced that people have an illness that is easily curable but simply won’t be treated.” He also feels a heavy responsibility. Many patients have his personal cell phone and call him when they have problems or good news about how they’re doing.
Some of those progress reports come much faster than in Israel’s home country. Before he implanted a pacemaker in a tall Massai in Kenya, the man had been picked on by his family because he wouldn’t help much with the hard work on the family peanut farm. “When I examined him, he had a pulse of 40,” Israel says. “It’s a miracle he was even standing upright, let alone hauling heavy bags.” After the surgery, Israel advised his patient to stay the night for observation, but the patient couldn’t wait to leave. Two hours later, he returned, covered in sweat. He’d been running sprints with his brothers to test the new device. Israel shakes his head. In Germany, it would be unthinkable for a patient to engage in athletics immediately after surgery. But the patient was exuberant: “I was the fastest!”
The success stories are notable partly because the challenges remain so steep. In Zambia, for instance, there is a single cardiologist; she determined to become one after losing her younger sister to an easily curable heart disease. Often, the hospitals not only lack pacemakers but also sterile surgery equipment, antibiotics and other essential material. Therefore, Israel and his team import everything they need for the surgeries, including medication. If necessary, they improvise. “I’ve done surgery with a desk lamp hanging from the ceiling by threads,” Israel says. He already knows that he will need to return to Kenya in six months to replace the pacemaker of one of his patients and replace the batteries in others. If he doesn’t travel, lives are at risk.