Creation of designed shape cell sheets that are noninvasively harvested and moved onto another surface

We developed a novel method to obtain designed shape cell sheets for tissue engineering. Shaping of cell sheets were achieved by the use of poly(N-isopropylacrylamide) (PIPAAm) and poly(N,N'-dimethylacrylamide) (PDMAAm) for temperature-responsive cell adhesive and cell nonadhesive domains, respectively. These polymers were covalently grafted onto tissue culture polystyrene (TCPS) dish surfaces by electron beam irradiation with mask patterns. At 37 degreesC, human aortic endothelial cells (HAECs) attached, spread, and proliferated to make a monolayer only on PIPAAm-grafted domains. HAECs did not adhere on PDMAAm-grafted domains for more than 1 month even under the serum-supplemented condition. By reducing the culture temperature below 32 degreesC, PIPAAm changed to hydrophilic and HAEC sheets were detached from PIPAAm-grafted surfaces without any need of an enzyme such as trypsin. Cell-cell junctions were retained in the recovered cell sheets and easily moved to virgin TCPS dishes with the aid of hydrophilically modified polyvinylidenefluoride membranes as a supporter during the transfer. Moved cell sheets rapidly adhered onto the dish surfaces, and the supporter was easily peeled off from the cell layers. HAEC sheets transferred to new dishes revealed the identical shape and size to those before transfer. This novel technique is the only way to create, harvest, and transfer designed shape cell sheets and would have promising applications in tissue engineering.