Estimating glucose diffusion coefficient of membranes for tissue engineering applications using Fick's First Law

The idea of growing artificial tissues in bioreactors such as hollow fibre membrane bioreactors (HFMBs) has started years ago and preparation of biocompatible porous membranes and scaffolds has been attempted extensively. There also have been several studies on modelling glucose transport processes in HFMBs. However, there is little information available that discusses specifically the glucose diffusivity across tissue engineering membranes or scaffolds and, importantly, its dependence on the properties of the materials (i.e., membrane and scaffold). Therefore, the objective of this study is to deduce the glucose diffusivity across different membranes. Using Fick's law and a diffusion cell in this study, we have determined glucose diffusion coefficients for two different membranes namely cellulose nitrate (CN) and polyvinylidene fluoride (PVDF). These membranes possessed similar pore size with varying thickness and were saturated with water and cell culture medium (CCM). The diffusion experiments were conducted in a thermostated water bath at either 27 or 37 +/- 1 degrees C. It was observed that PVDF membrane with greater thickness has a lower diffusivity than CN membrane when both were saturated in CCM and water at 37 degrees C. From the results, we derive the significance of the decrease of diffusion coefficient with increasing thickness of the membranes.