Thermoresponsive nanostructured surfaces generated by the Langmuir-Schaefer method are suitable for cell sheet fabrication.

Thermoresponsive poly(N-isopropylacrylamide) (PIPAAm)-immobilized surfaces for controlling cell adhesion and detachment were fabricated by the Langmuir-Schaefer method. Block copolymers composed of polystyrene and PIPAAm (St-IPAAms) having various chain lengths and compositions were synthesized by reversible addition-fragmentation chain transfer radical polymerization. The St-IPAAm Langmuir film at an air-water interface was horizontally transferred onto a hydrophobically modified glass substrate while regulating its density. Atomic force microscopy images clearly visualized nanoscaled sea-island structures on the surface. By adjusting both the composition of St-IPAAms and the density of immobilized PIPAAms, a series of thermoresponsive surfaces was prepared to control the strength, rate, and quality of cell adhesion and detachment through changes in temperature across the lower critical solution temperature range of PIPAAm molecules. In addition, a two-dimensional cell structure (cell sheet) was more rapidly recovered on the optimized surfaces than on conventional PIPAAm surfaces. These unique PIPAAm surfaces are suggested to be useful for controlling the strength of cell adhesion and detachment.