Imagine a strawberry, red and ripe, tucked into the freezer, or a head of lettuce accidentally frozen in the fridge. Then picture it days later, defrosted. It’s a mushy, unappealing mess. Now you roughly understand the challenge that organ transplant teams face every day keeping tissues fresh. Organs, like produce, don’t freeze well. The slightest bit of crystallization can burst cells, rip veins, and render a precious, carefully salvaged heart, lung, or kidney unusable.

Yet keeping organs cool is critical to maximizing their usable lifespan, keeping them viable for lifesaving organ transplant surgeries which often take place in another hospital if not another state.

The United Network for Organ Sharing is in charge of matching organs with potential recipients in the United States. Despite reports that 2022 was a record-setting year for liver, heart, and lung transplants, there are still far more people in need of a transplant than organs available. About 104,000 people are on a waiting list for transplants in the United States right now, with just under 60,000 of those people immediately eligible to receive an organ based on the severity of their illness. Some 42,000 transplants were completed last year. But roughly 6,000 of those eligible for transplant, or 17 people each day, will die this year while waiting for their new life-saving organ, according to government data.

Regardless of eligibility, when it comes to transplants, even a short delay can prove deadly.

Organs have just hours of viability once they are removed from living or dead donors. Under ideal conditions, a heart or lung currently has 4–6 hours, livers have 8–12, and kidneys have up to 36 hours of viability outside the body. Cooling organs helps preserve them, but it can also lead to the formation of ice crystals that damage delicate tissue, ruining donated organs. Now, a spate of startups are working on new ways to safely cool organs for longer and at lower temperatures.

“We are basically going through a revolution in transplantation.” “We are basically going through a revolution in transplantation,” says Korkut Uygun, a biomedical engineer and expert in organ preservation at Harvard Medical School. “There will be many devices, many protocols, many companies that compete.” Uygun expects a range of products targeted to specific organs, or specific transportation or storage needs, in the coming years, thanks to an influx of research dollars and new technology.

Chemist Xiaoxi Wei and her one-time classmate at the State University of New York at Buffalo, Mark Kline, hope to be among them. After graduate school, the two launched X-Therma, a cell, tissue, and organ preservation startup, back in 2015. Their goal was to develop a new generation of living medicine, whether through cell-based therapies or cryopreserved organs. It’s Wei’s brainchild, and she’s spent the past eight years talking to potential funders, supporters, employees, and, more recently, the FDA.

Wei’s story starts with a beloved grandfather, who died while waiting for a liver transplant when she was 8. Heartbroken, Wei vowed to find a way to bank usable organs for future patients. The story is still unfolding today.

Dimethyl sulfoxide (DMSO) is the standard chemical cryopreservative for cells. But for organs, the amount of dimethyl sulfoxide required for cryopreservation is difficult to diffuse evenly. Even when used to cryopreserve cell-based therapies, it can cause harmful side effects. Scientists are testing different methods of washing it away and trying different transplant procedures and transport devices. But it’s been tough to challenge long-established procedures.