In vivo experiments and numerical investigations on nanocryosurgical freezing of target tissues with large blood vessels.

This study presented the first in vivo animal experiments of using nano-cryosurgical modality to completely freezing tumor tissues embedded with large blood vessels, which is a tough issue to tackle otherwise. Three-dimensional theoretical simulations were also performed on the complex freezing problems by considering flow and heat transfer of blood flow in large vessels. According to the experimental measurements and numerical predictions, injecting the nanoparticles with high thermal conductivity into the freezing target can significantly reduce the heating effect of blood vessel, shorten the freezing time, and enlarge the freezing range. Most importantly, the introduction of nanoparticles successfully overcomes the classical challenges in completely ablating the tumor region with large blood vessel and enhancing the freezing efficacy of cryosurgery. This investigation consolidates the practical and theoretical foundation for nano-cryosurgery which suggests a highly efficient freezing strategy for treating late stage tumor.

A new nano-cryosurgical modality for tumor treatment using biodegradable MgO nanoparticles.

A new conceptual modality for nano-cryosurgical ablation of tumors is proposed in this article. The main strategy is to apply MgO nanoparticles (NPs), which are nontoxic, biodegradable, and have few side-effects on the human body, to mediate the freezing procedure effectively. Detailed investigation via animal experiments and nucleation analysis demonstrated that delivery of MgO NPs into the target tissues would significantly improve the cryosurgical outcome. The formation of an iceball during the freezing process is accelerated and enlarged due to the excellent thermal properties of MgO NPs. In addition this method could promote the generation of ice nuclei and thus enhance cryoinjury to the target cells. Therefore, combining the biodegradability and nontoxicity of MgO NPs with their relatively lightweight properties, excellent thermal properties would help develop a high-performance cryosurgery. These findings may lead to methods for safe and targeted nano-cryosurgery and possibly break through the barriers facing current clinical treatments of cancer. FROM THE CLINICAL EDITOR: Cryosurgery is a promising evolving modality to address malignancies. The work presented in this paper may add a novel concept to the field of nanomedicine by demonstrating that MgO nanoparticles enable more efficient ice-ball formation and cryoinjury in the target tissue.