Cell-sheet
technology is a well-known method by which cells are
grown on thermoswitchable substrates that become nonadhesive upon
cooling, such that a complete layer of adherent cells, along with
the produced extracellular matrix, detaches as a sheet. Polymers that
exhibit a lower critical solution temperature (LCST) below physiological
temperature in water, commonly poly(N-isopropylacrylamide)
(PNIPAM), are covalently grafted or, for block copolymers, physisorbed
onto substrates in a monomolecular thin film to achieve this. Consequently,
such substrates, and the polymers required for film formation, can
only be prepared in a chemical lab with profound macromolecular expertise.
In this study, we present an easy and robust method to coat standard
cell culture dishes with aqueous solutions of commercially available
poly(2-n-propyl-2-oxazoline) (PnPrOx), a polymer that exhibits LCST
behavior. Different standard cell culture dishes were repeatedly coated
with 0.1 wt % aqueous solutions of PnPrOx and dried in an oven to
create a fully covered and thermoresponsive surface. Using this PnPrOx
surface a variety of cell types including endothelial cells, mesenchymal
stem cells, and fibroblasts, were seeded and cultured until confluency.
By decreasing the temperature to 16 °C, viable cell sheets were
detached within cell-type dependent time frames and could be harvested
for biological analysis. We show that the cytoskeleton rearranges,
leading to a more contracted morphology of the cells in the detached
cell sheet. The cellular junctions between single cells within the
sheet could be detected using immunostainings, indicating that strong
and intact intracellular contacts are preserved in the harvested sheets.