A thermo-sensitive chitosan-based copolymer hydrogel was used for harvesting living cell sheets. The hydrogel was tested for harvesting 3T3 cells after carrying out cell culture at 37 degrees C and incubating the confluent cells at 20 degrees C for spontaneous detachment of cell sheets from hydrogel surface without enzyme treatment. Results from cell viability assay and microscopy observations demonstrated that cells could attach to the hydrogel surface and maintain high viability and proliferation ability. Cell detachment efficiency from the hydrogel was about 80%. The detached cell sheet retained high viability and could proliferate again after transferred to a new culture surface. (C) 2008 Elsevier B.V. All rights reserved.