| Summary: | 碩士 === 國立宜蘭大學 === 生物機電工程學系碩士班 === 104 === Control of ice crystallization plays an important role on the issue of cryopreservation. Ice crystallization always causes the biological cells to rupture or even to die. To know the extracellular ice formation could control the dehydration of cells during freezing. Thus, study on the phase diagram of suspending solution for cryopreservation become very significant for the temperature control could affect the dehydration of cells. However, it is hard to refer on the literature due to the lack of study on the field. For study on phase diagram, differential scanning calorimeter (DSC) is the common used equipment, but the expensive cost and difficult operation of DSC result the phase diagram of suspending solution seldom to be discussed. In this study, we use thermoelectric cooling chip (TEC) as a heat source and heat sink to construct a temperature control stage for the TEC DSC system. The self-developed TEC DSC system have the advantages of compact in size, cheap and easy operation. We calibrate the accuracy of the system according to the previous study. We discuss the crystallization temperature (Liquidus temperature ,TL) in the presence between the range of 0 and 40% sodium bromide (NaBr) at the cooling rate of 5 °C/min and the eutectic temperature (TE) of phase diagram of Water-NaBr is obtained in this study. The eutectic temperature is found as -28.86 ± 1.20°C. Compared with the previous work, the errors are less than 5.98°C and there is no significant difference to the t-test. Using the self-developed TEC DSC system to explore the phase diagram of Water-Sodium chloride (NaCl) system between the concentration of 0 and 25%, eutectic temperature is found as -18.60 ± 1.53°C. The phase diagram of Water-NaBr and Water-NaCl system are constructed and the specific heat is also discussed in this study. The results of this study could be applied on the traditional two-step cryopreservation protocol.
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