We have presented a mathematical model to simulate the cell growth on a scaffold, assuming that the size of an organoid is limited by the oxygen supply to the cells forming the organoid1). Oxygen transport occurs solely by diffusion in the organoid cultivated on a scaffold, and this situation imposes severe restrictions on the system; necrosis due to oxygen deficiency will occur in regions where the partial oxygen pressure is lower than a certain critical value. Figure shows an example of the results taken for the cylindrical organoid of hepatocyte ("cylindroids") cultivated in a hollow-fiber scaffold. The maximum sizes of the cylindroids estimated by the model coincides well with the experimental data presented in the previous literatures, showing the validity of the model. Based on the model, we make some concrete proposals for the optimal design of organoid-scaffold system and microbiochip on which cells are cultivated and handled.

Reference

1) Sumaru K., Kanamori T.: Optimal Design of Bio-Hybrid Systems with a Hollow Fiber Scaffold: Model Analysis of Oxygen Diffusion/Consumption, Biochem.Eng.J., 20, 127-136 (2004)

Figure Schematic illustration of the cylindroid/hollow-fiber system and corresponding p distribution of calculated for several values of α_fD_f/α_mD_m.