Effect of membranes on oxygen transfer rate and consumption within a newly developed three-compartment bioartificial liver device: Advanced experimental and theoretical studies.

A mathematical model is developed to predict oxygen transfer in the fiber-in-fiber (FIF) bioartificial liver device. The model parameters are taken from the constructed and tested FIF modules. We extended the Krogh cylinder model by including one more zone for oxygen transfer. Cellular oxygen uptake was based on Michaelis-Menten kinetics. The effect of varying a number of important model parameters is investigated, including (1) oxygen partial pressure at the inlet, (2) the hydraulic permeability of compartment B (cell region), (3) the hydraulic permeability of the inner membrane, and (4) the oxygen diffusivity of the outer membrane. The mathematical model is validated by comparing its output against the experimentally acquired values of an oxygen transfer rate and the hydrostatic pressure drop. Three governing simultaneous linear differential equations are derived to predict and validate the experimental measurements, e.g., the flow rate and the hydrostatic pressure drop. The model output simulated the experimental measurements to a high degree of accuracy. The model predictions show that the cells in the annulus can be oxygenated well even at high cell density or at a low level of gas phase PG if the value of the oxygen diffusion coefficient Dm is 16 × 10(-5) . The mathematical model also shows that the performance of the FIF improves by increasing the permeability of polypropylene membrane (inner fiber). Moreover, the model predicted that 60% of plasma has access to the cells in the annulus within the first 10% of the FIF bioreactor axial length for a specific polypropylene membrane permeability and can reach 95% within the first 30% of its axial length.

Experimental evaluation and theoretical modeling of oxygen transfer rate for the newly developed hollow fiber bioreactor with three compartments.

Bioartificial liver support provides a bridge to transplantation which is at present the only proven specific treatment for acute liver failure. In this paper, a novel multi-coaxial hollow fiber bioreactor so-called "Fibre-in-Fibre FIF Bioartificial liver device" with three compartments is experimentally and mathematically studied. The mathematical model in this paper is an extension of Krogh cylinder model for hollow fibre devices by including one more zone for oxygen transfer, i.e. oxygenation compartment. Three simultaneous linear differential equations were derived for pressure in plasma and cell compartments and flow rate in cell compartment. To validate the model, Oxygen Transfer Rate and hydrostatic pressure experimental measurements for different flow rates, 17-400 ml/min, and different number of hollow fibres pairs are used. Several important parameters of the Michaelis-Menten was investigated, namely, constant Vmax (the maximum oxygen consumption per unit volume of the cell mass), the oxygen partial pressure, the flow rate of the perfusate at device inlet. The results showed that the oxygenation compartment should easily secure Oxygen to the cells in compartment B.