Panagiotis G. Georgiou carefully adjusted the core of a tiny polymer nanoparticle, no wider than a strand of DNA, and watched something extraordinary happen: ice crystals that should have grown unchecked during thawing remained stubbornly small. At the University of Manchester, under the leadership of Professor Matthew Gibson, a team has overturned decades of scientific assumption about how synthetic materials can control ice. For years, researchers believed that only the surface of a molecule mattered when it came to stopping ice from forming large, damaging crystals—a process known as ice recrystallization. But this new study proves that what’s inside the particle is just as critical.
This discovery matters because uncontrolled ice growth ruins frozen biological samples, damages tissues in cryopreservation, and compromises the quality of frozen foods. Nature has long had a solution: ice-binding proteins in Arctic fish and insects that prevent ice from spreading. Scientists have tried to mimic these with synthetic materials, focusing almost exclusively on surface chemistry. The Manchester team, in collaboration with Professor Steve Armes FRS at the University of Sheffield, took a different approach. Using polymerisation-induced self-assembly—a scalable method that can be adapted for industrial production—they built nanoparticles with a water-exposed outer shell and a chemically distinct inner core.
What they found was unexpected. When the core was soft and flexible, the nanoparticles strongly suppressed ice recrystallization. When the core was rigid, the effect weakened. And when the core was chemically locked in place, the ice-controlling ability vanished entirely. This internal structure, hidden from direct contact with ice, was somehow influencing the freezing process. The researchers believe individual polymer chains inside the particle may become active during temperature shifts, dynamically interacting with ice in ways previously unimagined.
The implications stretch far beyond the lab. These nanoparticles could lead to better cryopreservation techniques for transplant organs, more stable vaccines, improved frozen foods, and even anti-icing coatings for aircraft. Unlike natural antifreeze proteins, which are expensive and difficult to produce at scale, these synthetic particles can be manufactured efficiently and tuned for specific needs—without altering their surface, which might trigger immune responses in medical applications.
“This work shows that we can tune ice-controlling properties by engineering the inside of nanoparticles, rather than just their surface,” says Professor Gibson. “This means we can fine-tune performance without affecting how the particle interacts with its environment.” It’s a new design principle for functional materials—one that opens a hidden dimension in nanotechnology. As research continues, the ability to control ice from within could quietly transform how we freeze, store, and protect some of the most fragile and vital materials on Earth.