Research On Cooling And Rewarming Methods For Vitrification Of Biological Materials Based On Microchannel

Cryopreservation is the most promising way for long-term storage of biological samples e.g., cells and cellular structures, which is of great significance for both scientific research and clinic application. Vitrification cryopreservation overcomes solute and ice damage caused by the traditional method of cryopreservation of cooling and rewarming process of biological material, which has now become the mainstream of research in the field of cryopreservation of biological materials. Vitrification require ultra-high drop rate of rewarming, but the existing cooling and rewarming method has significant deficiencies. A novel on-chip cryopreservation method was proposed herein, and several fundamental issues were investigated based on studying the mechanism of the microchannel heat transfer inherent in two stage of vitrification of cooling and rewarming process.First, by introducing of microchannel heat transfer principle,the thermal and mechanical effect during the on-chip cooling/warming process was studied theoretically. Based on the theoretical model, the influences of system structures, geometry, material and operation condition on the cooling/warming process were investigated. Then the approaches for optimal design of the on-chip system as well as accurate control of the cooling/warming rate were established.Second,Combining with theoretical simulation studies, The cooling and rewarming experimental platform for vitrification is designed and set up,which include pressure-driven means design, data collection design, stainless steel vessel design, structural design of the test section. Copper with good thermal conductivity is used to manufacture the different channels of lengths and thickness of the microchannel chip.Thirdly,The heat transfer characteristics of the cooling and rewarming experimental system is studied by experimental method. Using liquid nitrogen as the cooling fluid, 80% concentration of alcohol as a rewarming fluid, different channels of different length and thickness of micro-channel chip were analyzed in a large number of experiments under different operating pressures, get the sample rate of the variation of the different channel length and different thickness of samples of the principle under different operating pressures.Through this topic research, a new method is initially created for biomaterials vitrification. The way to achieve a wide range of flexible cooling and rewarming, in particular, which achieve a larger volume of the object(tens to hundreds of microliters) ultrahigh cooling and rewarming(>55000℃/min). Relatively compared to conventional method it achieve a great breakthrough and has a broad application prospect and important social value, which has created a the new situation for the application of vitrification technology.