Effects of spatial variation of cells and nutrient and product concentrations coupled with product inhibition on cell growth in a polymer scaffold

The effects of spatial variation of cells and nutrient and product concentr ation, in combination with product inhibition in cell growth kinetics on ch ondrocyte generation in a polymer scaffold, are analyzed. Experimental stud ies reported previously have demonstrated spatial dependence in the cultiva tion of chondrocytes. In the present study, the cell-polymer system is assu med to consist of two distinct phases. The cells, fluid, polymer matrix, an d extracellular matrix comprise one phase, and the other phase consists of a fluid and polymer matrix. The only two species in the fluid considered to affect cell growth are the nutrient and product. The multiphase transport process of these two species in the cell-polymer system is described by the species continuity equations and corresponding boundary conditions for eac h individual phase. A volume-averaging approach is utilized for this system to derive averaged species continuity equations for the nutrient and produ ct concentrations. The volume-averaging approach allows for a single specie s in a two-phase system to be represented by a single averaged continuity e quation. Competitive product inhibition, saturation kinetics of substrate, and cell population control are assumed to affect the cell growth kinetics. A modified Contois growth kinetic model is used to represent the three fac tors that affect cell growth. A parameter analysis is performed and the res ults are compared qualitatively with experimental data found in the literat ure. (C) 1999 John Wiley & Sons, Inc.