Macrophages behavior on different NIPAm-based thermoresponsive substrates.

Thermoresponsive materials and surfaces are widely used in cell culture applications. There is a lot of research work employing thermoresponsive materials with various structure and compositions. However, little is known about the immunological response to the thermoresponsive materials. Macrophage-like transformed murine cell line RAW264.7 was selected as it is a widely used standard model for immune activation analysis. This study proposes to compare the effects of thermoresponsive films with various compositions on macrophage cells. Thermoresponsive materials are a useful utility as a non-enzymatic harvesting system for tissue culture. As RAW264.7 cells are difficult to remove from the substrate by enzymatic methods we also explored the possibility to use thermoresponsive materials for the macrophage cultivation. Spin coating and solvent casting was used to produce films of N-isopropylacrylamide-based polymers from the nanometer to micrometer range. Successful cell adhesion and proliferation was highly dependent on the thickness and composition of the coating. RAW264.7 cells were successfully detached from the coatings upon temperature reduction. Furthermore, results indicate that the RAW264.7 cells remained inactivated as cell secreted cytokine remained at a low level and the surface receptor profile of RAW264.7 was not altered when cells were detached in this manner.