Abstract
Thin film evaporation is an efficient phase change heat transfer style, and could achieve ultra-high cooling rate if it was applied for cells vitrification. In this paper, an experimental study for prostate cancer cells vitrification was done. The cells ultra-high speed freezing method was based on thin film evaporation of liquid nitrogen. In order to examine the feasibility of the new method, the comparison experiments, in which the other two generic approaches of cell cryopreservation were used, were done. The methods were respectively the equilibrium freezing method and the open pulled straws vitrification method. At the same time, the influences of the concentration of cryoprotectant on cooling rate and cell survival rate were analyzed. The results showed that the ultra-high speed freezing method based on thin film evaporation can obtain higher cooling rate and better cell survival rate than the other two conventional cryopreservation methods. It preliminarily proved the feasibility of this method applied to the cells vitrification process. In addition, both the cooling rate and the cell survival rate are affected by the concentration of the cryoprotectant in the cell suspension. The cooling rate decreases with the concentration of the cryoprotectant increasing, but cell survival rate increases first and decrease afterwards with the increase of the concentration of the cryoprotectant, in which an optimum value exists. This study will promote the practicality of the new ultra-fast cell freezing method.
