Study on Magnetic Induction Nanowarming of Vitrified Whole Rat Kidneys

Magnetic nano-rewarming is a promising approach to solve the problem of long-term vitrification preservation of organs at deep low temperature. Here, we test the colloid stability and the heating properties of magnetic iron oxide nanoparticles in VS55 cryoprotectant solutions. The results show that magnetic VS55 solutions remain colloidally stable for a long time even after vitrification and nano-rewarming. The heating properties of magnetic VS55 increased with the increasing of alternating magnetic field current and nanoparticle concentrations. MRI results show that the uniform loading and complete wash out of nanoparticles in rat kidney tissues can be basically achieved by perfusion. After vitrification and nano-rewarming, the overall structure of the whole rat kidney remains intact while the internal blood vessel network may be partially damaged. This work demonstrates that the faster and more uniform rewarming can be achieved by optimizing the perfusion loading process, improving the magnetic field strength or the nanoparticle heating performance, etc. Thus, the challenge of organ vitrification cryopreservation rewarming may be solved in the near future.