TitleImproving the post-thaw processing of cryopreserved red blood cells using a combined approach of mathematical modeling and microfluidics
Publication TypeThesis
Year of Publication2014
AuthorsLusianti, RE
UniversityOregon State University
CityCorvallis, Or.

Cryoprotectants (CPAs) such as glycerol and dimethyl sulfoxide (DMSO) are commonly used during cryopreservation of cell based therapeutics. Although these additives are beneficial during freezing, it is often desirable to remove them before infusion into a patient. Currently, the most common method for CPA removal is by centrifugation. This method is time consuming, labor intensive, and can also lead to significant cell losses. In this study, we investigate the possible use of a microseparation device for removal of CPAs from red blood cell suspensions. A mathematical model was developed to predict the CPA removal performance of the device and cell volume changes during the process. Experiments to ascertain the permeability properties of several different types of membranes of interest were conducted using the device. The resulting experimental values were then incorporated into the model to make CPA removal predictions. To assess the accuracy of the model predictions, glycerol removal experiments from solutions without red blood cells were carried out. Through comparison of the experimental data and the model predictions, it was found that the model could accurately predict CPA removal for membranes with sufficiently small pores where mass transfer is dominated by diffusion; but in membranes with larger pores where mass transfer is dominated by pressure driven flow, the model predicted values that are lower than what was obtained through experiments. The reason for this effect is the pressure discrepancy that was found between the pressure drop recorded during the experiment and the model predicted pressure drop. The model predicted pressure drop assumes ideal fluid flow condition whereas the actual conditions during the experiment indicates the presence of air bubbles trapped inside the channels, obstructing the flow of fluid and possibly altering the surface area available for mass transfer. Parametric studies using model simulations on the CPA removal performance of the membranes with smaller pores were conducted. Through parametric studies, CPA removal trends and cell volume changes during the process using the membranes of interest were better understood. The information gained from this study is useful for designing the next prototype of the microseparation device as well as for developing an optimal CPA removal protocol for red blood cell suspensions.

URL https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/df65vd2