关键词: 神经干细胞球, 保护剂添加模型, 因素分析, 渗透损伤

Abstract: In this paper a mathematical model of mass diffusion during the cryoprotectant addition for neural stem cell sphere is presented.The mass diffusion equation is established separately for intracellular and extracellular spaces but taking into account the mass exchange across the cell membrane.The volume change of cells in different positions is also simulated when cryoprotectant is added step by step.The factors affecting volume change are analyzed.Different procedures of addition are used to investigate osmotic damage.The results shows that change of DMSO in extracellular space,which can attain stable within 10 s near the surface and 15 s close to the center of the ball,is faster than that in the intracellular element.Decreasing L_p and increasing ω can greatly improve the volume change while the impact on the size of neural stem cell spheres is limit.The multi-steps addition procedures,which keep the same osmotic pressure difference in each step while gradually reduced time durations,should be chosen.In addition,four-step addition is better than other stepwise additions.An ideal continuous addition should combine with low concentration difference and short loading time,and convex curve addition patterns are preferred.

Key words: neural stem cell spheres, CPA addition model, factor analysis, osmotic damage