LAUSR

Three-dimensional (3D) multicellular cell spheroids (MCSs) are excellent in vitro cell models, in which, e.g., the in vivo cell-cell interaction processes are much better mimicked than in conventional two-dimensional (2D) cell layers. However, the difficulties in the generation of well-defined MCSs with controlled size severely limit their application. Herein, low-adhesive poly(vinyl alcohol) (PVA) hydrogels structured with inverted pyramid-shaped microwells were used to guide the aggregation of cells into MCSs. The cells settling down into the microwells by gravity accumulated at the central tip of the wells and then gradually grew into spheroids. The size of cell spheroids can be straightforwardly controlled by the culture time and initially seeded cell number. The MCSs generated in a parallel microarray format were further used for drug testing. Our results suggest in agreement with complementary literature data that the cell culture format plays a critical role in the cellular response to drugs, and also confirms that spheroids possess a much higher drug resistance than cells in 2D layers. This novel microstructured PVA hydrogel is expected to offer a potential platform for the facile preparation of spheroids for various applications in the biomedical field.