Simulated confluence on micropatterned substrates correlates responses regulating cellular differentiation.

Abstract

While cells are known to behave differently based on the size of micropatterned islands, and this behavior is thought to be related to cell size and cell-cell contacts, the exact threshold for this difference between small and large islands is unknown. Furthermore, while cell size and cell-cell contacts can be easily manipulated on small islands, they are harder to measure and continually monitor on larger islands. To investigate this size threshold, and to explore cell size, cell-cell contacts, and differentiation, we use a previously established simulation to plan experiments and explain results that we could not explain from experiments alone. We use five seeding densities covering three orders of magnitude over 25-500 µm diameter islands to examine markers of proliferation and differentiation in bone marrow-derived mesenchymal cells (cell line). We show that osteogenic markers are most accurately described as a function of confluence for larger islands, but a function of time for smaller islands. We further show, using results of the simulation, that cell size and cell-cell contacts are also related to confluence on larger islands, but only cell-cell contacts are related to confluence on small islands. This study uses simulations to explain experimental results that could not be explained from experiments alone. Together, the simulations and experiments in this study show different differentiation patterns on large and small islands, and this simulation may be useful in planning future studies related to this study.