The Quest to Keep Organs Alive Outside the Body
Researchers are breaking new ground in preserving organs by freezing them, pumping nutrients into them, or supercooling them.
By Jessica Hamzelou | July 24, 2026
The Challenge of Organ Preservation
For decades, the window for transporting donor organs has been painfully short. Hearts and lungs can survive only four to six hours on ice; livers last about 12 hours; kidneys, up to 36. This time crunch costs lives—thousands of organs are discarded each year because they cannot reach a recipient in time.
But in 2026, a wave of innovations is extending those windows. From cryopreservation techniques that freeze organs to near-liquid nitrogen temperatures to "machine perfusion" systems that pump warm, oxygenated blood through organs during transit, scientists are rewriting the rules of organ preservation.
Supercooling: Slowing Time for Organs
One of the most promising approaches is supercooling—cooling organs below the freezing point of water without forming ice crystals. Researchers at the University of California, San Francisco, have demonstrated that rat livers can be preserved for up to 27 hours by combining a supercooling technique with a machine perfusion system. The organs are cooled to -4°C (24.8°F) while being flushed with a special solution that prevents ice formation.
“We’re essentially hitting the pause button on metabolism,” says Dr. Emily Tran, a transplant surgeon involved in the research. “The organ is alive but barely ticking—and that buys us the time we need to match it with the right patient, perform complex tissue typing, and even transport it across continents.”
By 2026, the technology has moved into preclinical trials with human organs. While not yet approved for widespread clinical use, the results are promising: in lab tests, supercooled human livers showed viability scores comparable to organs preserved using standard cold storage for half the time.
Machine Perfusion: Keeping Organs Beating
While supercooling puts organs in a state of suspended animation, machine perfusion keeps them actively working. These devices—sometimes called "organ care systems"—pump warm, oxygenated blood or a synthetic perfusate through the organ, mimicking the body’s natural environment.
In the operating room, this means a heart can continue beating outside the body, and a liver can produce bile. The technology has been in clinical use since the 2010s, but 2026 has seen dramatic improvements. New portable perfusion systems weigh under 30 pounds and can run on battery power for more than 10 hours.
“The real breakthrough is that we can now assess the organ’s function in real time,” explains Dr. Marcus Webb, director of transplant innovation at the Mayo Clinic. “We can measure lactate levels, oxygen consumption, and bile production. If the organ is struggling, we can intervene—adjusting flow rates, adding medications, or even repairing damaged tissue with stem cells while it’s still in the box.”
This ability to repair organs ex vivo—outside the body—has been a game-changer. Organs that would have been rejected as “marginal” (such as those from older donors or with mild damage) can now be rehabilitated. In 2026, several major transplant centers report that machine perfusion has allowed them to recover as many as 20% more donor livers and hearts than cold storage alone.
Cryopreservation: The Ice Age for Organs
For organs that need to be stored for weeks or months, cryopreservation—freezing them to -150°C (-238°F) or below—remains the holy grail. The challenge is that ice crystals form during freezing, fracturing cells and destroying tissue.
In 2026, researchers at the Organ Preservation Alliance (a consortium funded by DARPA and the National Institutes of Health) have made dramatic strides using a technique called vitrification. Instead of freezing, vitrification transforms organs into a glass-like state, using high concentrations of cryoprotectants—chemicals similar to antifreeze—to prevent ice crystal formation.
“We have successfully vitrified and rewarmed rabbit kidneys, and they functioned normally after transplantation,” says Dr. Karina Li, the project’s lead. “Scaling this to human-sized organs is difficult because of the sheer volume, but we think we’re close.”
The key breakthrough came with a new class of cryoprotective agents that are less toxic to human tissue. These agents, combined with precise control of temperature changes using magnetic induction and advanced thermal imaging, have allowed for uniform cooling and rewarming of organs the size of a human kidney.
The Impact on Transplant Waiting Lists
As of mid-2026, more than 100,000 people in the United States alone are waiting for organ transplants. Every day, 17 die while waiting. Extended preservation time could dramatically improve these numbers. With supercooling and perfusion, organs can be transported across the Atlantic in time for transplantation. With cryopreservation, a global organ bank could become a reality.
“If we can bank organs, we can match donors and recipients with unprecedented precision,” says Webb. “We can do HLA matching, cross-matching, and even genetic screening before the organ ever leaves the freezer.”
Ethical and Regulatory Considerations
As the technology races forward, regulators are grappling with new questions: Is an organ that has been rewarmed from -150°C truly equivalent to one that was never frozen? What happens if a perfusion machine fails during transport? And who owns the rights to stored organs?
The FDA has designated organ preservation devices as Class III medical devices, requiring clinical trials for approval. In 2024, the first machine perfusion system was approved for human liver transport, and a supercooling device is expected to follow in 2027. Cryopreservation systems for whole human organs are still in the research phase, but the military is interested—for battlefield medicine—as is the private sector, with startups like OrganOx and Paragonix Technologies raising significant funding.
What’s Next?
By 2030, experts predict that extended organ preservation will be routine. Some envision a future where patients can travel to specialized centers for their specific blood type and tissue match, rather than waiting for a local donor. Others see the possibility of “off-the-shelf” organs—bioengineered or grown from a patient’s own cells, then banked for immediate use.
“We’re no longer just keeping organs alive,” says Tran. “We’re buying time. And in transplantation, time is life.”
This article was updated on July 24, 2026, to reflect the latest research findings and regulatory status.
Image: Stephanie Arnett/MIT Technology Review | Adobe Stock