Influence of Transition Metal Dichalcogenide Surfaces on Cellular Morphology and Adhesion

This article presents the effect of transition metal dichalcogenide (TMD) surfaces and their geometric arrangements on resulting cellular morphology and adhesion. WS₂ and MoS₂ on SiO₂ and polydimethylsiloxane (PDMS) substrates were utilized as cell culture platforms, and cell-substrate interactions were probed via analysis of cellular morphometric features (i.e., cell area and circularity) of neonatal human dermal fibroblasts (NHDFs) and metrology of TMD surfaces. It was quantitatively confirmed that the presence of TMDs on substrates resulted in an overall enhanced cellular morphology, even on SiO₂ substrates adverse to cellular adhesion. On a localized scale, distinct TMD geometric features at sites of adhesion were measured and correlated with the observed cell morphology. Geometric parameters of TMDs, including TMD island count and total TMD area, exhibited positive correlations with the resulting morphology of cells by enhancing cellular areas and elongations. Further, geometric properties were compared to cell area per TMD island, and positive correlations were observed with TMD island size parameters. Cells adhered at heterogeneous locations with combinations of exposed TMD and SiO₂, demonstrating an enhanced morphology in relation to the number of TMD islands in a cell's local area and the geometric size parameters of TMD islands within the cell's operating length scale. The proposed mechanisms of cellular adhesion on TMD-modified surfaces are attributed to the role of surface properties (e.g., stiffness, friction, and hydrophobicity) of TMD and underlying SiO₂ and their combined effects during progressive stages of cellular adhesion. These findings provide insight toward possibilities of tailoring adhesion of cells guided by geometric parameters of TMDs.