Morphology and differentiation of human mesenchymal stem cells cultured on a nanoscale structured substrate

Abstract

Mesenchymal stem cell (MSC) is known to show responsiveness to the physical properties, such as stiffness and nano to microstructures, of the extracellular environment. However, the signaling mechanism has not been fully elucidated yet. Here, the effects of nanoscale pillar arrays of the cell culture substrate on morphology and differentiation were evaluated in human MSC to understand the signaling mechanism in regulation of differentiation in response to the nanoscale structures. Human MSCs were cultured on a quartz substrate with the three types of pillar-arrays with 200 nm in side length, 150 nm in height, and different center-to-center spacings (300, 400, and 700 nm) in a cell culture medium with no differentiation induction regent. The cells were well spread, and about half of the cells showed osteogenic differentiation on the flat region of the substrate. The spreading and the osteogenic differentiation were suppressed in the cells on the pillar-arrayed region regardless of the pillar spacing. This provided insight that the human MSCs spontaneously differentiate into the osteoblast in response to the stiff substrate with no structure, and the suppression of the cell spreading caused by the nanoscale structures can downregulate the progress of the osteogenic differentiation.