Modelling Of Cell Suspention During Cryopreservation.

Abstract

In the present study, One-dimensional numerical model for cryopreservation is developed to design a mathematicalmodel that allows prediction of the transient temperature and solute concentration distributions and corresponding cell responses at any location (in the solidified,mushy, and liquid regions) in a cell suspension during cooling processes. The continuummodel for binary component phase change systemis considered for simulating the freezing process of binary solution(H2O−NaCl ). The formalism is extended to the freezing of a cell solution. An implicit scheme for coupling temperature and concentration fields in solidificationmodel is employed. Mathematical predictions of the un-steady state temperature profile,mushy region and eutectic composition are obtained and then using the temperature and salt concentration data, the kinetics of water loss and survivability of model cell are predicted. The equine sperms is modeled as a cylinder of length 36.5ìm and radius of 0.66ìm with an osmotically inactive cell volume (Vb) of 0.6V0, where V0 is the isotonic cell volume. The volumetric shrinkage during freezing of equine sperm suspentions at holding temperature between −200C and −500C in the absence of cryoprotective agents (CPAs) for differnt initial solute concentrations of 5%and 10%is predicted. The percentage of viable equine sperm was 13% and 8% at holding temperature of −380C and −250C for initial solute concentraion of 5%and 10%respectively. Spermviability is found to be almost constant between −250C and −400C for an initial solute concentration of 10%.