Multilayered mouse preosteoblast MC3T3‐E1 sheets harvested from temperature‐responsive poly(N‐isopropylacrylamide‐co‐acrylamide) grafted culture surface for cell sheet engineering

A novel temperature‐responsive tissue culture surface was prepared using ultraviolet irradiation to graft poly(N‐isopropylacrylamide‐co‐acrylamide) (PNIAM‐co‐AM) onto commercial tissue culture surfaces. The physical properties of the grafted surfaces were confirmed by Fourier Transform Infrared Spectroscopy, contact angle measurement, and Atomic Force Microscopy. The grafted surface was also tested and shown to be nontoxic using mouse preosteoblast MC3T3‐E1 cells. The cells grew as successfully on the grafted surface as those on ungrafted surface. When the temperature was reduced from 37 to 10°C for 30 min, followed by 20°C for 60 min, the confluent cells could be detached as a continuous sheet. A histological examination showed that the harvested cell sheet preserved tight junctions and extracellular matrix proteins, allowing the sheet to adhere to other cell sheets as multilayers. The resulting multilayered sheets were in good condition, as indicated by the LIVE/DEAD stain.