Nanotopography Influences The Osteogenic Differentiation Of Mesenchymal Stem Cells

Life cannot exist without cell, while cell cannot survive without the extracellular matrix (ECM). Through changing cell shape and the actin cytoskeleton, topography of the ECM can affect a range of cellular processes, including cell migration, proliferation and differentiation. Microfabricated nanotopography can not only support cells culturing in vitro, but also influence their behaviors, for instance, guiding stem cell differentiation, which is one of the two goals of stem cell research. In this paper, our goal is to direct a specific differentiation of mesenchymal stem cells (MSCs) into osteoblasts by using only the nanotopographical cues.MSCs are the most widely used stem cells because they can be easily harvested from bone marrow besides their ability to differentiate into many cell lineages, such as osteoblasts, chondrocytes, adipocytes and neurocytes. We used MSCs isolated from the young Sprague-Dawley rats in this study.In this paper, we fabricated polystyrene inverse opal films with different pore sizes through self-assembled SiO2 colloidal templates. After stretching to certain length, the inverse opal films became like porous meshes. The above materials were used for cell culture.The results showed that both the inverse opal films and the porous meshes could induce osteogenic differentiation of MSCs. The effect was slightly enhanced with the pore size increasing, while reducing on the over stretched films during the late stage, suggesting that MSCs cultured on nanotopography experience a threshold feature size for differentiation. This study is significant for surface design of nanoengineered functional biomaterials.