Adult pluripotent stem cells, such as mesenchymal stem cells derived from bone marrow and adipose tissue are capable of multilineage differentiation. Although autologous stem cell transplantation is an effective alternative to organ transplantation, the loss of cell viability and differentiation confinement of implanted cells has largely impaired the therapeutic efficacy. To produce biomaterial-free liver construct to integrate into living tissue, we isolated adipose mesenchymal stem cells and subjected them to a delicate culture configuration to mediate the hepatocyte differentiation. The differentiated hepatocyte-like cells were then inoculated onto poly (N-isopropylacrylamide) (PNIPAAm) grafted cell culture dish. By lowering the culture temperature to 20 degrees C, cells detached from the dish surface into a complete cell sheet. Hematoxylin and eosin staining and immunohistochemistry results showed that cell sheet was composed of 2-3 layers of cells and extracellular matrix was maintained intact. As compared with traditional cell harvest using trypsin digestion, cell sheet fabrication causes no damage to cell membrane and extracellular matrix. Hence, cell sheets would form a better interaction with tissues in situ, and a higher cell viability and therapeutic efficiency would be expected.