A Study Of Mass Transfer In Cryopreservation Of Neural Stem Cells

The cryopreservation technique of neural stem cells (NSCs) is very important for clinical application and scientific research.Neural stem cells were cultured in-vivo. Assays including the biological morphology and properties, Tryptan Blue Dying and Hochest/PI Fluorescein Stain Method were carried out to demonstrate the cultured cells' multiplication capacity. So the experimental materials'activity and supply sufficient cells could be ensured for latter researches.The osmotic pressure technique was used to test the CPA concentration. The results showed that osmotic pressure technique is much efficient and effective.Two CPAs were chosen to examine the effects of the operation temperature, CPA type and the interactions between solutes on the CPA transport within cells during the CPA addition. Results showed that the osmosis damage and the toxicity damage are two major factors for the cell's low viability.Micro-photography technique was employed to measure the osmotically inactive cell volume, and it was determined to be 0.391V0.The k-k model and 2-P model to describe CPAs transport during the single and multiple CPA addition in a one-dimensional model tissue with a low cell density such as neural stem cells were presented. The three permeability parameters were obtained. NSCs membrane permeability parameters for K-K model of DMSO and EG was determined:DMSO: Lp=0.172μm/min atm,ω=8.980×10-2μm/s, a=0.92; EG:Lp=0.198μm/min atm,ω=7.880×10-2μm/s,σ=0.90and that for 2-P model of DMSO and EG were DMSO: Lp=0.168μm/min atm,ω=9.081×10-2μm/s; EG:Lp=0.174μm/min atm,ω=8.009×10-2 These results can be used to guide the selection of the optimal CPA addition protocol.