Investigation of Electromagnetic Resonance Rewarming Enhanced by Magnetic Nanoparticles for Cryopreservation.

The lack of an effective rewarming technique restricted the successful cryopreservation of organ or large tissues by vitrification. The conversion of electromagnetic (EM) energy into heat provides a possible solution for the rewarming process for the cryopreservation. In this work, an EM resonance rewarming system was set up with dynamic feedback control and power feeding optimization. In addition, we take advantage of magnetic nanoparticles (MNPs) to absorb magnetic field energy to further enhance the energy conversion efficiency. We achieved a >200 °C min-1 rewarming rate for tens of milliliters of cryopreserved samples. Besides, we also investigated the effect of nanoparticle size and concentration based on thermal properties by analyzing the contribution of nanoparticles and the utilization of field energy. The closed system reduced the possible concomitant side effects when increasing the number of nanoparticles or increasing the EM source power. With the remarkably low dosage of nanoparticles (0.1 mg mL-1 Fe) compared to that for other MNP-based rewarming applications, this study opens the door to new approaches for exploring novel techniques for tissue and organ preservation.