Novel device for transplantation of cell sheet and evaluation of thin polymer films by atomic force microscopy

Cell therapy is expected to a new tool to treat refractory diseases. In heart regeneration, it has been firstly conducted with needle injection of cell suspensions. Recently, cell sheet engineering emerged as another method of cell therapy. Cell sheet is prepared with a temperature responsive dish by temperature reduction. It is a thin-patch-like tissue construct and its thickness is several tens of micrometers. It is composed of cells and intrinsic extra cellular matrix only. The transplantation of the cell sheet has been already conducted in animal experiments and even in clinical trials. The cell sheet is transplanted at the surface of the heart, but it is difficult to transplant the cell sheet under the beating heart. To overcome this difficulty, we designed a device that was composed of two thin polymer films that have different friction. The films were made of polyurethane, polyethylene, or polypropylene. The cell sheet was set up on the device by sandwiching it with the less frictional film and the more frictional film. In this paper, using two different films having the different friction, the cell sheet was successfully transplanted to the static round polymer surface, the harvested heart, and even the beating heart of pig by removing the films step by step using the difference in friction. Also, surface properties such as friction, adhesion force and roughness of the films were studied by an atomic force microscopy (AFM). From the results of the study, the friction of the film was found to be likely proportional to the adhesion force and the inverse of roughness.