Microstructuring thermoresponsive gel using hysteresis towards 3D cell assembly

In this paper, we conducted an assembly of microstructures made of a thermoresponsive gel using hysteresis character of the thermoresponsive polymer solution. This method can be used for 3 dimensional cell assembly by embedding cells in the thermoresponsive gel structures. Gel sheets can be fabricated by micrheaters on a substrate and maintained in the gel condition by the hysteresis character. The microstructures can be formed by assembling the gel sheets using a probe device. The generation of a thermoresponsive gel was conducted using the microheaters made of ITO on a substrate and the generated gel sheets were manipulated by a micromanipulator. The fabrication of a gel sheets was achieved using the hysteresis character and the fabricated gel sheets were picked and placed by the probe. The positioning of the gel blocks can be precisely controlled by the micromanipulator. The results indicate the method we propose has a great possibility to achieve 3D cell assembly without large stress to cells during the assembly and cell culture.