Fig 1. Concept of the cell density homogenization method using Ekman transportation.

(a) Schematic diagram of the initial cell distribution after seeding with a pipette. The cell density around the edge of the dish is higher than that at the center of the dish. (b) A swirl flow is induced by rotating the dish along a circular orbit. (c) Due to the swirl flow, a secondary flow directed toward the center is induced in the cell suspension. The cells accumulated around the edge are moved to the center of the dish.