For the almost 520,000 Americans who will undergo treatment this year, the process leaves little room for a full life. An innovative new device could change everything.

With a small click, Jshon Thomas connected himself to his life support. It was the last step in an hour-long process involving hundreds of steps that Thomas completed with the precision of an airline pilot prepping for a transcontinental flight. Even though the 59-year-old violinist and learning and development professional had heard this percussive snap hundreds of times -- Thomas hooks up to the NxStage System One dialysis machine and Pure Flow water recycling system in his living room four times a week -- he still checked off each step of the four-page list in black pen. If everything went right, Thomas's dialysis machine would easily remove toxins from his blood that his failed kidneys no longer could. Today was not one of those days.

For the first two hours of his treatment, the machine hummed along like a washing machine on a perpetual spin cycle. Thomas swaddled himself in layers of blankets and settled into his seat. Then a shrill alarm began beeping. Thomas's husband, Gary Carson, opened the machine, revealing a spaghetti platter of wires. The cause of the problem was somewhere in the miles of tubing, and if Thomas didn't want to stop his treatment early, he had to find it -- quickly. A call to tech support didn't start out promising: "Have you tried turning it off and turning it back on again?"

Thomas and Carson turned knobs and flipped switches, all while keeping an eye on the time. At least once a week, it seemed, Thomas's machine malfunctioned, and the Bay Area couple would have to problem-solve on the fly. Initially, Carson and Thomas remained calm. They had dealt with this scenario countless times before. But as the seconds ticked by, the duo grew tense. If the issue persisted, Thomas would have to record his vitals by hand -- a tedious task. If it shut down completely and the pair couldn't restart it after four minutes, his blood could begin to clot. They would have to empty his blood from the machine and begin a new session. Thomas could do little but call out suggestions. Maybe it was the router and not the machine? A minute ticked by. Carson rebooted. Another minute passed. The pair waited with tech support. Then, as abruptly as it began, the beeping stopped. The only sound remaining in the den was the whir of the dialysis machine and two sighs of relief.

For Thomas and the nearly 520,000 Americans who rely on dialysis, the experience can be uncomfortable, time-consuming, and fraught with health risks. On the surface, dialysis machines are fundamentally simple. "It's a pump and a filter­. Everything else is bells and whistles," says Jonathan Himmelfarb, MD, a nephrologist and cofounder of the healthcare startup Kuleana Technology. But that simplicity can be hard to design.

Take the dialyzer, a special filter that removes the bloodborne toxins. The dialyzer isn't like a coffee filter. Instead, it is made up of around ten thousand hollow polymer fibers only slightly thicker than a human hair. During dialysis, toxin-laden blood fills the mile of microscopic plastic tubing, which is bathed in a salty fluid called dialysate. The polymer allows toxins to diffuse across the filter into the dialysate, which is then dumped down the drain, while clean blood is pumped back into the body. A single dialysis session requires more than 100 liters of dialysate to remove the toxins that have built up between treatments.

Himmelfarb, 70, has spent decades caring for patients like Thomas who spend their lives astride the dividing line between living and dead. For nearly 40 years, Himmelfarb's professional life has been ruled by the reality that dialysis sucks. "It's very expensive, the patients are very unhappy, outcomes are relatively poor, and there's a rather short lifespan," says Buddy Ratner, a Kuleana Technology cofounder and professor of bioengineering and chemical engineering at the University of Washington.

Convincing investors and grant agencies that dialysis sucks is the easy part. Getting them to back an alternative is more challenging. Also hard?

Building a dialysis machine that is safe, portable, and easy to use. It's one of the reasons dialysis technology has changed little since Himmelfarb first donned a white coat in 1983. To alter the status quo, Himmelfarb and other innovators have to not only try to replicate the biological functions of the human kidney but also take on corporate behemoths raking in millions under the current system. Competitions like the Kidney X Prize have spurred interest, but the payoffs aren't lucrative enough to overcome the expensive hurdles in bringing a better dialysis machine to market.

Himmelfarb knows patients have long hoped for a miracle device that could make dialysis easier. "Then the light bulb clicked," he says. "We have to be that hope."

After years of work, Himmelfarb and Ratner brought their revolutionary new dialysis device, called AKTIV (Ambulatory Kidney to Increase Vitality), just inches from clinical trials. Rather than relying on hundreds of liters of special fluid, the machine uses a novel photochemistry approach to help neutralize toxins that have been filtered from the blood into the dialysate, thus reducing the amount of liquid needed for the treatment. Since it is the size of carry-on luggage, it would allow patients to dialyze anywhere.

But just as Himmelfarb's team was starting the last round of studies needed before they could begin testing in large animals, the center where he and his colleagues worked shut down. They would need a new plan -- and additional funding -- to continue pushing for a future with better dialysis.

The first symptoms of kidney failure are silent. Failing kidneys can't remove extra fluid from the body, nor can they filter molecules like urea, which can be toxic in high dosages, from the blood. Until disease has robbed the kidneys of 90 percent of their function, renal failure can often go unnoticed. What signs do appear -- fatigue, anemia, swelling -- don't carry a neon sign shouting "kidney disease." As the two fist-size organs continue to decline, the body swells -- first the limbs, then the abdomen. By then the body contains so much extra fluid, sometimes as much as 50 pounds, it can become hard to breathe. Without medical intervention, coma and death eventually follow.

Dutch physician Willem Kolff knew the signs well. He and his colleagues didn't have many options for renal patients in the 1930s and '40s. But Kolff knew from other research that the high levels of urea in the patients' blood was killing them. He reasoned that if he could find a way to remove the urea, he could keep his patients alive. Building an artificial kidney, however, wouldn't be easy.

"The kidney is one of the most complex organs," explains Suzanne Watnick, MD, a Scholar in Residence at the American Society of Nephrology. "To replicate that is tough." The kidneys use a two-part process to filter blood. Each kidney contains a million individual tiny clusters of cells called nephrons, which are themselves made up of a glomerulus and tubule. First, the glomerulus filters the blood, removing small molecules, including urea, water, and electrolytes. Then the tubule returns everything but waste to the bloodstream. What Kolff needed was a way to remove urea from the blood without stripping off all the other components the body needed. His salvation came in the form of sausage.

Then, as now, butchers typically made sausage casings from animal intestines or cellophane, an early bioplastic made of cellulose. The latter option grabbed Kolff's attention because it could create what chemists call a semipermeable membrane. Experiments in animals told him that if he filled a sausage-shaped cellophane tube with toxic blood and rocked it in a salty solution, the cellophane would allow the urea to diffuse into the solution while keeping other blood components, such as large proteins and red blood cells, inside. Kolff built machine after machine as World War II raged. (In his spare time, he helped hide around 800 people from the Nazis.) The result was a dialysis machine prototype that consisted of 20 meters of sausage casing wrapped around an aluminum drum. Kolff removed a patient's blood via a large hollow needle connected to a rubber tube, which would direct blood into the sausage casing. As the drum turned, the blood-filled cellophane casing would then be dipped in the salty dialysate bath, allowing urea to flow across the casing and into the dialysate by osmosis. Periodically, Kolff poured off the used dialysate and replaced it with fresh liquid. Clean blood would then be pumped back into the patient. His setup contained only a fraction of the nephron's complexity and responsiveness, but after a series of failed human trials, Kolff successfully dialyzed his first patient in a municipal hospital in Kampen, about 60 miles northeast of Amsterdam, on September 11, 1945. He chronicled his success in a 1947 treatise, writing that "With this patient we have in fact provided proof that it is possible to save the life of persons with acute uraemia by the use of the artificial kidney ... she gave us the decisive impetus to continue along the road we had set out on."

Kolff moved to the United States in 1950 -- four years prior to the first kidney transplant -- and continued modifying his original design to make it more efficient. He cannibalized Maytag washing machines for their large drums and eventually used beer and fruit juice cans as makeshift drums. (Maytag, less than enthused about Kolff's misuse of its product, allegedly sent him a letter barring him from any future purchases.) Iterations of Kolff's many inventions -- including the artificial heart and a component of the heart-lung machine -- are still used today.

In the ensuing decades, inventors continued to miniaturize the process and developed a slew of new devices to address kidney failure, many of which now lie in state at the dialysis museum at the Northwest Kidney Centers headquarters, just south of Seattle. By the end of the 1960s, engineers had developed two machines, nicknamed the Monster and the Mini-Monster, that were used in the first home dialysis treatment and formed the basis of many of the machines used today.

Still, the thorniest problem was finding a way to remove blood from the patient and safely return the filtered product. The blood's natural ability to clot can be lifesaving if you have a wound, but it created major problems for dialysis equipment. And veins could endure only so much poking with giant needles before they collapsed. Physician-scientists had tried to circumvent these problems by using anticoagulants to thin blood, and in 1960 University of Washington nephrologist Belding Scribner debuted his game-changing "Scribner Shunt," which could be permanently installed in a patient's arm for easy and repeated access to the bloodstream.

What emerged was the modern hemodialysis machine that patients could use indefinitely, even from the comfort of their own bedrooms. But the machines were scarce, and the expertise to operate them even rarer, which made affordable dialysis a healthcare unicorn. It took a 1972 act of Congress to make dialysis a near-universal entitlement for Americans.

Himmelfarb began practicing nephrology roughly a decade after the landmark 1972 bill.

Himmelfarb, who has dark eyes and wisps of gray hair creeping along his temples, became fascinated with the renal system during his residency at Maine Medical Center in Portland. Soon after, he pursued two nephrology fellowships. "Dialysis, as a life-sustaining therapy, was pretty miraculous in those days -- and yet very complicated," Himmelfarb says.

During one of his fellowships, he studied cellulose -- which Kolff had used in his casings -- to understand what happened when blood came in contact with a foreign surfaces. Blood clotted, yes, but the cellulose also switched on the inflammatory response. Over time, this frequent state of inflammation reduced the body's ability to fight pathogens -- a major problem for dialysis patients. He was drawn to the complexity of nephrology and relished its technical challenges.

Then there were the patients. The intensity of the relationships that physicians formed with their patients over time -- as those patients experienced chronic kidney disease, began dialysis treatment, and sought transplants -- felt incredibly rewarding to him. But there was work to be done.

While Himmelfarb's patients all expressed gratitude for the artificial kidneys that were sustaining their lives, they also shared dismay as to how constrained their lives were. As a nephrologist, Himmelfarb could calculate whether his patients with end-stage renal disease were receiving adequate dialysis, but that didn't change the fact that dialysis itself was fundamentally inadequate. The United States now spends more on dialysis than any other country and has the worst outcomes. And, according to the Centers for Disease Control (CDC), more than half of the 800,000 or so Americans with end-stage kidney disease belong to a racial or ethnic minority. While 1972's landmark Public Law 92-603 ensured more people would gain access to life-saving dialysis treatment, there were still systemic issues in the field of dialysis care that needed to be addressed.

In the U.S., most patients go to a specialized clinic three days a week, four to five hours at a time, to receive dialysis. Two multinational corporations, Colorado-based DaVita Inc. and German-owned Fresenius, dominate the American dialysis industry. Insurers such as U.S. Centers for Medicare & Medicaid Services pay clinics a set rate for providing dialysis, creating an industry that market research has valued at $26 billion annually. "A number of organizations are making, let's call it, a pretty steady stream of guaranteed income coming in from the federal government," Ratner explains. "So why shake that up?"

Some dialysis clinics will even shorten sessions in order to increase the number of patients they can treat each day. These shortcuts can push patients to the physiological edge, according to Fokko Wieringa, a principal scientist at IMEC in the Netherlands. The blood becomes thick and the heart struggles to pump. Blood pressure plummets; the brain and muscles are starved of oxygen. If this happens repeatedly, the heart thickens and stop working. Perhaps not surprisingly, some dialysis patients say they tend to feel worse post-treatment than before.

Furthermore, patients face a significant risk of infection if the equipment and injection sites are not thoroughly sterilized before treatment. One 2023 study found that one out of every 10 deaths among dialysis patients resulted from infection. In 2020 alone, one in three of the 14,000 documented infections in dialysis patients were caused by the tough-to-treat Staphylococcus aureus (staph) germ, which can enter a patient's bloodstream through the access point on their arm, the CDC notes. In an effort to lower infection risk, U.S. government agencies have worked with clinics in recent years to update procedures, train staff, and raise awareness.

In many areas of medicine, like cardiology and diabetes management, competition has been transformative, says Diane Alexander, a health economist at the University of Pennsylvania. That there are really only two market leaders in the dialysis space could contribute to the lack of innovation, she explains, while noting the current system favors the in-center care these companies provide, and may not support breakthroughs, such as miniaturization, designed for in-home treatments. Other technologies in healthcare have miniaturized, she says, "We haven't seen that in dialysis."

The machines remain large, loud, and laborious to use. Patients learning to do home dialysis require months of intensive classes to learn the hundreds of steps to connect and disconnect from a dialysis machine. This complexity is one of the reasons that only around 10 percent of dialysis patients receive treatment at home.

What's more, Himmelfarb explains, dialysis doesn't replicate the full range of kidney functions. Kidney cells use specialized proteins to sniff out tiny changes in blood chemistry and make adjustments on a minute-by-minute basis. The greatest engineering minds in the world haven't been able to replicate this ability, says Ratner. Dialysis, which mainly removes toxic uric acid, doesn't even come close. For a long time, the fact that dialysis kept patients from dying led to an attitude of it being good enough. That attitude is slowly changing, but the industry has a lot of catching up to do. Dialysis hasn't "changed substantially in 40 years," says Watnick. "It's truly archaic."

Himmelfarb wasn't satisfied with the status quo. Few nephrologists were, he admits, but without the engineering chops to rebuild a machine from the ground up, they could make little headway. In 2016, however, Himmelfarb met Ratner, who had the requisite engineering know-how. The pair immediately geeked out over discussions of water purification, dialysis filters, and Italian food. They recognized that dialysis's biggest challenge wasn't the procedure itself but rather the vast volumes of water needed to filter the blood.

With a $15 million Northwest Kidney Centers grant, Ratner and Himmelfarb founded the Center for Dialysis Innovation (CDI) at the University of Washington. Their quest was as simple as it was ambitious: to make dialysis better.

As soon as he learned his kidneys were failing, Thomas changed almost everything about his life. He began swimming laps at his local community pool to manage his hypertension. Dietary changes also helped him lose over 100 pounds. For nearly a decade, Thomas held the need for dialysis at bay until a blood test in late 2022 told him the day had come. Even for someone who'd already radically altered his lifestyle, dialysis came as a shock.

Thomas and his husband spent months learning how to dialyze at home. A vascular surgeon permanently connected the artery and vein in Thomas's left forearm, creating a fistula that would enable the rapid blood flow through the dialysis machine. First, he must ensure the water he will use is pure. He then boots up the dialysis machine, and checks his vitals. Next, he disinfects the injection site with alcohol and iodine wipes and multiple changes of nitrile gloves, gently threads two large-bore needles into his arm, and begins cycling his blood through the machine. After three and a half to four hours of dialysis, he repeats the process in reverse. More wipes, more gloves, more needles, more time. A total of six or seven hours will pass between the first step of his treatment and the last.

Thomas is grateful for dialysis. Without it he would die. But the process is also a huge burden. "It is a part-time job that I don't get reimbursed for," he says. Thomas and Carson hired contractors to redesign their basement. He needs a dedicated room to run his machine -- a big ask in the pricey Bay Area -- and bookshelves once crammed with vinyl records and stacks of sheet music are now filled with gloves, face masks, and alcohol wipes.

Then there are the demands on his time. If he didn't need dialysis, Thomas says, he could more easily work normal hours and travel. He wouldn't have the stress that accompanies a machine malfunction or have to plan his entire life around his treatment. Other than a transplant, for which he's currently waitlisted, a smaller artificial kidney is his only chance to untangle himself from the machine.

People in patient focus groups have shared Thomas's priorities. They want something that is small and portable, a machine that wouldn't anchor them to a room or clinic -- qualities that are fundamentally incompatible with a machine that guzzles hundreds of liters of water per treatment. Any team working in this area would have to tackle the dialysis thirst trap and design a better way to remove toxins in the blood. It didn't take long for engineers to identify alternatives.

Himmelfarb's office on the 6th floor of Harborview Hospital in Seattle provides us a panoramic view of the city when I visit him in February 2024. Droplets of rainwater sparkle like diamonds on the windows of nearby skyscrapers, giving the otherwise gray city a warm glow. This glimmer also inspired a CDI engineer and frequent collaborator of Ratner's and Himmelfarb's, Bruce Hinds, to create the innovation at the heart of the AKTIV device.

Cleaning the outsides of windows on a high-rise usually requires a lot of rope and a brave person with a squeegee. Much of the dust and dirt encrusting these windows is organic material, including everything from bird droppings to pollen. Days baking in the sun only made the grime darker and harder to remove. To cut down on costly cleaning, glass companies began coating skyscraper windows with a thin layer of titanium dioxide. When UV light hit the titanium dioxide -- the same compound used in many sunscreens -- it spurred a chemical reaction that could break down the organic material and allow any remaining dirt to be washed away in the rain. If photochemistry could clean skyscrapers, the engineers thought it might be able to do the same thing for blood. "It was a breakthrough concept," Himmelfarb says.

In a traditional dialysis machine, used dialysate is discarded and replaced with fresh fluid. Instead of dumping it down the drain, the Seattle researchers ran spent dialysate through a special compartment crammed with titanium dioxide nanowires and LED lights. The resulting chemical reaction converts toxic urea into harmless nitrogen and carbon dioxide. Without the additional liquid, Himmelfarb and Ratner were able to shrink the refrigerator-size standard dialysis machine to the size of a carry-on suitcase. And when the team ran preliminary tests of the AKTIV's efficiency using cow's blood spiked with varying levels of urea in 2023, they found the AKTIV could remove 15 grams of urea (the average amount made by a human) in 24 hours with just a single liter of dialysate. By that time, Himmelfarb and Ratner had spun out a company, Kuleana Technology, to commercialize and test the device, which they hoped would move into human trials by 2025.

Ratner says the team is working to improve the photooxidation system's-- catalytic efficiency. In other words, can they squeeze more inches of titanium dioxide nanowires into the device? Additionally, he explains, they're using computer models to map the toxin-filled dialysate's flow and ensure it is efficiently transporting as much urea as possible to the catalyst for breakdown. Ultimately, Himmelfarb says his primary concern is funding: "Everything else is solvable."

Their $15 million grant was a one-time offer, so the team worked to cobble together additional funding. But then, in April 2024, the University of Washington decided to close the Center for Dialysis Innovation. AKTIV had earned media buzz and was approaching readiness for human trials, but Ratner and his colleagues would still need to scramble to keep up the momentum. There was no guarantee the AKTIV would make it to patients.

While Himmelfarb and Ratner charted a new course, other startups are exploring methods to shrink the size of a dialysis machines.

Singapore's Vivance (formerly AWAK Technologies) has developed a way to recycle used dialysate using special materials called sorbents. These compounds, designed to sop up specific types of molecules-, can be found in gas masks and diapers. In dialysis, sorbents like ferric oxide hydroxide and activated carbon can be used to remove toxins and positively charged ions from dialysate, thus reducing the amount of water needed for a single dialysis session from 120 liters to just 1 to 2 liters. While many details about Vivance's design remain proprietary, the company uses an enzyme to convert urea to ammonia, and a sorbent mixture to remove the ammonia and other ions. In late 2023, Vivance pulled in a second round of funding worth $20 million in preparation for a U.S.-based clinical trial.

Qidni Labs in Buffalo, New York, is also developing a sorbent-based device, dubbed Qartridge. Founder and CEO Morteza Ahmadi won't share specifics of how Qartridge works due to pending patents, but he says the device uses a variety of sorbents to clean the spent dialysate enough for reuse. To Ahmadi, the sorbent technology is a game-changer for dialysis. He built a mini-clinic test lab using Qidni equipment in under a week for less than $5,000. The machine "is truly portable and nearly waterless," he says. To date, the Qidni machine has been pilot tested in 15 patients and Qidni Labs is currently recruiting for clinical trials.

To Kevin Longino, CEO of the National Kidney Foundation, the biggest challenge facing these innovators is figuring out how to turn a profit in the American dialysis system, where Medicare pays the bulk of the bills. Large dialysis clinics have spent a lot of time and money to work within the current system. Without a clear path forward, many investors hesitate to open their pocketbooks. "You're talking several hundred million dollars of capitalization required to do a dialysis machine," Longino says. "For decades, you just didn't have anybody that wanted to go into the space."

This spring, Himmelfarb's phone rang. Mount Sinai Hospital in New York City -- the first hospital to conduct dialysis treatment in the United States -- was looking to build a kidney disease innovation center, and they needed a team of top-notch nephrologists. Would Himmelfarb be interested?

In this new role, Himmelfarb is co-directing the Mount Sinai Center for Kidney Disease Innovation alongside Kirk Campbell, MD, president of the National Kidney Foundation. Though Himmelfarb has traded rain showers and rolling hills for the hustle and bustle of New York City, the collaboration with his colleagues at the University of Washington will continue.

So will Kuleana Technology. Himmelfarb and Ratner are optimistic the newfound distance won't slow their progress; meetings once held over coffee will now be conducted over Zoom. In 2023, the Department of Defense awarded Kuleana Technology, the University of Washington, and Brooke Army Medical Center, in San Antonio, Texas, a $4 million grant to conduct animal trials. Ratner anticipates AKTIV will be ready to test in sheep or pigs in a year or two and, if all goes to plan, in humans by 2026 or 2027.

Funding remains a perpetual issue, and researchers are wary of the potential for large dialysis organizations to snap up disruptive technologies and shelve them. It's the exact opposite of what Himmelfarb envisions for the AKTIV. "If it doesn't go all the way to patients, then it didn't succeed," Himmelfarb says, jabbing his desk with an index finger to add a percussive exclamation point to each word.

For Thomas, that progress can't come soon enough. He hasn't been able to travel home to South Carolina to visit family since he started dialysis, and his weeks are carefully planned so that he can fit in treatment, violin practice, and time at the gym and with friends. With transplant waitlists so long in California, Thomas and Carson have even contemplated a temporary move to Las Vegas to improve Thomas's chances at receiving a kidney.

Meanwhile, the mechanical symphony within Thomas's dialysis machine will beep and buzz and whir like it has hundreds of times in the past. It's not the orchestral swell Thomas dreamed of when he learned the violin so many years ago, but it will be the song that runs his life until he gets the call that, finally, a kidney is ready for him.