冷冻保护剂对神经干细胞球导入过程的模拟分析

Numerical Simulation of Mass Diffusion During Cryoprotectant Loading for Neural Stem Cell Sphere

建立了以刚性球孔隙模型为基础的神经干细胞球的冷冻保护剂导入模型。在结合跨膜传质扩散的基础上,分别对细胞内空间和细胞外空间列传质扩散方程,并通过计算,得出了不同条件下细胞内外浓度以及细胞膜两侧浓差随时间和空间的变化曲线。从结果中可以看出,细胞外的保护剂浓度变化较快,在第5 s即可接近渗透平衡;细胞内的保护剂浓度变化则较为平缓。保护剂扩散系数对于导入过程影响不大,增加神经球尺寸及溶质胞膜渗透系数可以有效地减少导入过程中的细胞浓差。低温导入过程中细胞浓差较常温导入时更大,对细胞的渗透性损伤也更为强烈。研究结果对优化冷冻保护剂的导入程序有重要的指导意义。

Based on the hard sphere porous model a mathematical model of mass diffusion during the cryo-protectant loading for neural stem cell sphere was presented.The mass diffusion equation was established separately for intracellular and extracellular spaces but taking into account the mass exchange across the cell membrane between the intracellular and extracellular elements.The simulation concentration profiles of the cryoprotectant at different times and spaces indicate that the change of protectant DMSO（dimethly sulforide） in extracellular space,which can attain stable within 5 s,is faster than that in the intracellular element.The diffusion coefficient of the protectant does not obviously influence the loading process,while the increase of neural stem cell sphere diameter and solution permeability of the cell membrane can reduce the concentration difference between the intracellular and extracellular elements effectively.The concentration difference is more significant when the diffusion occurs at low temperature,which can bring stronger osmotic damage in contrast to the process at room temperature.The results are of significance for the optimization of the cryo-protectant loading procedure.