Stem cell differentiation: Multipotency retained

Matthew Dalby and colleagues describe a materials solution in which mesenchymal stem cells (MSCs) cultured on a nanostructured substrate maintain their multipotency for up to eight weeks. Dalby and collaborators hot-embossed polycaprolactone substrates to pattern square-shaped pits. 120 nm in size, arranged in a square lattice with a separation of 180 nm between the pits. The authors then cultured MSCs on the nanopatterned substrates as well as on planar ones. They observed that MSCs cultured on the pitted substrate maintained an undifferentiated state for up to eight weeks, whereas cells on the control (planar) substrates rapidly differentiated into various cell types, thus demonstrating that the topography of the substrate has a profound effect on the preservation of multipotency. The cell's cytoskeleton, which influences a broad range of cellular activities in a tension-dependent manner, interacts with the substrate through focal adhesions multiprotein structures through which regulatory signals are transmitted.