Concave/Convex\nCurvature of Anisotropic Grooves Differentially\nAlters Cellular Morphology, Adhesion, and Proliferation

Curvature is an integral part of the complex <i>in vivo</i> tissue architecture across various length scales.\nTherefore, several <i>in vitro</i> models with a patterned\ncurvature in different\nlength scales have been developed to understand the role of this in\ncellular behavior. At the subcellular scale, wavy patterns have been\nreported wherein concave and convex grooves are adjacently present.\nHowever, the independent effect of continuous subcellular concave\nand convex shapes has not been reported, mainly owing to the limitations\nin fabricating such patterns. In this study, we developed continuous\nconcave and convex grooves on polydimethylsiloxane (PDMS) using a Dracaena sanderiana (bamboo) leaf as a template.\nThe first (negative) replica from the abaxial side of the bamboo leaf,\nwhich imparted concave grooves on PDMS, was subsequently used as a\ntemplate to fabricate a positive replica of the leaf, resulting in\nconvex grooves of the same size and arrangement as the concave grooves.\nWe examined the influence of the groove curvature on the morphology\nof bone marrow-derived human mesenchymal stem cells (BM-hMSCs) and\nskeletal muscle cells (C2C12). BM-hMSCs and C2C12 cells aligned on\nboth concave and convex grooves as compared to the random orientation\non a flat substrate. The significant difference was observed in the\nmorphology of both cells, in terms of area, aspect ratio, number,\nand length of protrusions on concave and convex patterns. We found\nthat the number of protrusions was also dependent on the ratio of\ncell to pattern length scale for convex-shaped grooves but independent\nof length scale for concave-shaped grooves. The proliferation of BM-hMSCs\nwas also found to be different on concave and convex shapes. Therefore,\nthis study shows the importance of (1) convex and concave curvatures\nof the subcellular length scale in cellular response, (2) dependence\non the ratio of cell and curvature length scale, and (3) use of natural\ntemplates for overcoming fabrication challenges.