Morphological Changes of Human Mesenchymal Stem Cells on a Large Area of Nanopatterned Surface

Cells receive various physical and chemical signals from their tissue's microenvironment. In this study, human mesenchymal stem cells were cultured on variously sized nanostructures and their cellular responses were evaluated. Various nanotopological structures were fabricated on polystyrene polymer surfaces using anodized aluminum oxide (AAO) with different nanopost diameters (70, 200, 400 nm) as nanoimprinting templates. Before cell culture experiments, nanopatterns were coated with collagen types I and IV. Human mesenchymal stem cells were cultured on the various nanotopological structures for 24 h. Cell viability in the nanopatterned surfaces was evaluated by a live/ dead assay which showed that various nanostructures do not affect cellular viability. Cellular viability in all the samples was more than 95%. Cell proliferation assays showed that cells cultured on 70 nm nanostructures pre-coated with collagen type IV increased proliferation rates three folds compared to those of control, 200 nm, or 400 nm surfaces. Additionally, the cell area showed significant differences between samples cultured on 70 nm nanopatterned pre-coated with collagen type IV surfaces compared to other conditions. However, Nanopatterned surfaces pre-coated with collagen type I showed no significant differences between samples cultured on a 70 nm nanopatterned surface compared to the other samples. This result reflects that cells showed differential reaction depending on surface coated ECM proteins as well as nano structures. The effect of pre-coated ECM proteins is one of the major determinants that guides cellular reactions and nanopatterned surfaces could be used to further guide stem cell differentiation and proliferation.