低温保护剂去除方法与若干相关问题研究

发布时间：2018-03-28 21:37

本文选题：低温保护剂　切入点：渗透压　出处：《中国科学技术大学》2015年博士论文

【摘要】：本文针对低温保护剂的去除过程,从若干方向上进行了相关研究。本文首先简述了低温保存技术的若干关键问题,介绍了低温保存技术中的常用方法与材料,以及细胞低温损伤的分子生物学机制,并给出了一些常用的低温保护剂及其应用。本文中基于离散化的传质模型,提出了对稀释一过滤型低温保护剂去除系统的理论优化来进一步减少细胞损伤与去除时间。该方法中稀释液流速通过程序控制,使得每个循环周期中的低温保护剂去除量达到最大,同时将细胞体积膨胀一直控制在容许限度以内。结果表明优化的稀释液流速可以有效地缩短低温保护剂去除时间,与固定的稀释液流速相比减少了超过50%。该方法在血液流速较低、稀释区域体积较大、低温保护剂初始浓度较高、或细胞体积膨胀的容许限度较低时表现尤为突出。这种方法很好的解决了稀释一过滤系统中保证细胞回收率同时又尽量减少低温保护剂去除时间的要求,在实际临床应用中非常适合于冻存血液的快速输血准备。在低温保护剂的去除过程中,理论上完全避免细胞渗透性损伤的最优化操作条件,是基于细胞参数均一化的假设而得出。然而,由于细胞多分散性,该条件一般难以达到。本文中基于离散化传质模型,通过引入三个随机细胞参数,统计分析了多分散性对细胞回收率的影响。结果表明,细胞多分散性的存在导致实际的细胞回收率与理想值发生了偏离。这些偏离随着细胞参数标准差的增大而进一步增大,同时还受到低温保护剂初始浓度的影响。考虑到细胞多分散性,在均匀分布下得到的最优化血液或稀释液流速需要进一步完善。实际应用中,则需要采用更保守的血液或稀释液流速来进一步减小细胞的渗透性损伤。本文同时研究了基于微流控技术的低温保护剂去除方法,设计并实现了一种基于微流控技术的低温保护剂去除芯片,可以连续地进行低温保护剂的去除,同时评估了一些去除过程中对效率造成影响的因素,并通过实验加以验证。结果表明这种低温保护剂去除芯片可以对一定量的细胞实现低温保护剂去除的效果。由于微流控芯片的流速限制,该方法比较适合于少量而珍贵的样本。同时,本文在结果中分析了微流控方法中对去除效率及细胞存活率的影响因素,可以为低温保护剂去除芯片或其他类型的混合一分离结构微流控芯片提供一定的参考价值。
[Abstract]:In this paper, the removal process of cryopreservation agent is studied from several aspects. Firstly, some key problems of cryopreservation technology are briefly introduced, and the common methods and materials of cryopreservation technology are introduced. The molecular biological mechanism of cell hypothermia injury and some common hypothermia protectants and their applications are also given. Based on the discrete mass transfer model, a theoretical optimization of the dilution-filter low-temperature protective agent removal system is proposed to further reduce cell damage and removal time. In this method, the flow rate of the diluent is controlled by program. At the same time, the cell volume expansion is kept within the allowable limit. The results show that the optimized dilution flow rate can effectively shorten the removal time of the cryogenic protectant. Compared with the fixed diluent flow rate, the method reduces the flow rate by more than 50%. This method has lower blood flow rate, larger volume in the dilution area, and higher initial concentration of low temperature protectant. Or when the allowable limit of cell volume expansion is low, this method is a good solution to the need to ensure cell recovery while minimizing the removal time of cryogenic protectors in a dilution filtration system. It is very suitable for rapid transfusion preparation of frozen blood in clinical application. In the process of removing cryogenic protectants, the optimal operating conditions for completely avoiding cell permeability damage are theoretically based on the assumption of homogenization of cell parameters. Based on the discrete mass transfer model, the influence of polydispersity on cell recovery is statistically analyzed by introducing three random cell parameters. The existence of cell polydispersity leads to the deviation between the actual cell recovery and the ideal value, which increases with the increase of the standard deviation of cell parameters. At the same time, it is also affected by the initial concentration of low temperature protectant. Considering the polydispersity of cells, the optimal flow rate of blood or diluent obtained under uniform distribution needs to be further improved. More conservative blood or diluent flow rates are needed to further reduce cell permeability. At the same time, this paper studies the removal method of low temperature protectant based on microfluidic technology, and designs and implements a low temperature protectant removal chip based on microfluidic technology, which can continuously remove the low temperature protectant. At the same time, some factors that affect efficiency in the process of removal are evaluated. The results show that the microfluidic chip can remove a certain amount of cells. Because the flow rate of microfluidic chip is limited, This method is suitable for a small number of precious samples. At the same time, the factors influencing the removal efficiency and cell survival rate in the microfluidic method are analyzed. It can provide some reference value for removing chip or other kinds of mixed-separation microfluidic chip with low temperature protectant.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R318.52

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