Spheroid Formation Of Human Keratinocyte: Balancing Between Cell-Substrate And Cell-Cell Interaction

BACKGROUND: The formation of spheroids is tightly regulated by intrinsic cell-cell and cell-substrate interactions.OBJECTIVE: The chitosan (CS)-coating was applied to investigate the driven force directed the spheroid formation.METHODS: The effects of CS on cell functions were studied. Atomic force microscopy was employed to measure the cell-biomaterial interplay at single cell level.RESULTS: HaCaT cells shifted from their flattened sheet to a compact 3D spheroidal morphology when increasing CS-coating concentration. The proliferative capacity of HaCaT was preserved in the spheroid. The expression and activation of integrin beta 1 (ITGB1) were enhanced on CS modified surfaces, while the active to total ratio of ITGB1 was decreased. The adhesive force of a single HaCaT cell to the tissue culture plate (TCP) was 4.84 +/- 0.72 nN. It decreased on CS-coated surfaces as CS concentration increased, from 2.16 +/- 0.26 nN to 0.96 +/- 0.17 nN. The adhesive force between the single HaCaT cell to its neighbor cell increased as CS concentration increased, from 1.15 +/- 0.09 nN to 2.60 +/- 0.51 nN.CONCLUSIONS: Conclusively, the decreased cell- substrate adhesion was the main driven force in the spheroid formation. This finding might serve as a design criterion for biomaterials facilitating the formation of epithelial spheroids.