Science just pulled a kidney out of a deep freeze and made it work again. University of Minnesota researchers report pig kidneys cooled to about −150°C, banked for days, weeks — and in one case over a year — were rewarmed, pinked up with blood, and produced urine.
MIT Technology Review’s Jessica Hamzelou details the breakthrough shared as a bioRxiv preprint (not yet peer-reviewed). Transplant surgeon Erik Finger and bioengineer John Bischof’s team vitrified the organs into a glass-like state with cryoprotectants, then infused iron-oxide nanoparticles. An electromagnetic field flips those particles to heat the organ evenly — nanowarming — so ice and cracks don’t kill the tissue on the way back up.
Pig kidneys are roughly human-sized (~100 grams vs. a rat kidney’s ~1 gram), which is why this jump matters. Rewarmed kidneys on perfusion machines and in short pig transplants made urine within about a minute, though output ran around two-thirds of normal and cryoprotectant injury still showed. Finger walked out after the last transplant and called it “a big deal.” Outside experts called it a long-sought milestone toward indefinite organ banking.
Today’s transplant window is roughly 24–36 hours. A real freezer bank could flip the script: organs waiting for patients instead of patients dying on waitlists. Next hurdles: longer animal survival studies, less-toxic cryoprotectants, then human kidneys.
One organ. One year in the ice. Urine on demand. The organ-bank future just stopped being sci-fi cosplay.
Sources: MIT Technology Review — Pig kidneys frozen for a year brought back to life · bioRxiv preprint — Functional recovery of vitrified nanowarmed pig kidneys
Featured image: AI-generated editorial illustration by Bugle Blast.










