Nanowarming Technique Revolutionizes Organ Transplantation

A new two-step method that utilizes nanoscale magnetic rods to safely rewarm frozen tissues could improve the long-term preservation of donor organs. This technique offers an alternative to existing time-restricted methods and opens the door to more life-saving transplants.

Vitrification allows for long-term, damage-free preservation of organs by keeping fluids in a glass-like, amorphous state, unlike conventional freezing that turns liquids into crystalline ice. However, uniform and rapid heating is essential to prevent ice crystal formation.

Researchers from the Universities of Minnesota and California, Riverside, have developed a two-step method to safely and quickly thaw and rewarm organs using nanoscale magnetic rods.

Innovative Method Uses Iron Oxide Nanoparticles to Rapidly Thaw Frozen Tissues with Magnetic Field-Induced Heating

Their approach involves iron oxide nanoparticles, which, when exposed to an alternating magnetic field, generate enough heat to rapidly thaw animal tissues stored at -238 °F (-150 °C) in a cryoprotective solution. The process works by creating eddy currents in the electrically conductive iron oxide, which produce resistive heating due to the resistance encountered by these currents at the material’s surface.

Although the initial experiment succeeded, the researchers were worried that uneven distribution of nanoparticles in the tissues could create localized ‘hotspots,’ potentially causing tissue damage and toxicity from the melted cryoprotective agent. To address this, they introduced a second step.

Enhanced Method Uses Magnetic Fields to Safely Rewarm Frozen Tissues with Silicon-Coated Iron Oxide Nanoparticles

The researchers applied their enhanced method to animal tissues submerged in a solution with silicon-coated iron oxide (Fe3O4@SiO2) nanoparticles and a cryoprotective agent, which were then frozen with liquid nitrogen. They used an alternating magnetic field to quickly rewarm the tissues, as in the previous experiment. However, this time, as the samples neared the cryoprotective agent’s melting point, they introduced a horizontal magnetic field to disrupt and realign the nanoparticles, thereby reducing the rate of heat production.

The researchers observed that heating slowed most in tissue areas with higher nanoparticle concentrations, addressing their concerns about potential damaging hotspots. When they tested the two-step process on pig carotid arteries, over 80% of the cells remained viable after a few minutes of rewarming, indicating that the method is both quick and safe.

With over 100,000 people currently on the US organ transplant waitlist and a new addition every eight minutes, the researchers believe their method’s precise control over tissue rewarming could enhance long-term organ preservation and increase the number of life-saving transplants.

Read the original article on: New Atlas

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