Increase of expansion rate and direction control of microgel actuators for single cell manipulations

We propose a partial-constraint and side constraint fabrication process of gel actuators to increase expansion rates and control direction of actuation. We patterned dextran as a sacrificial layer to realize partially peel off gel actuator from a substrate. Furthermore, we change the constraint location from bottom to side of gel actuator by peeling off from a substrate. By decreasing constraint area and changing constraint location, we succeeded in increasing volume expansion rates of gel actuators from 1.7 to 5.0 and length expansion rates of gel actuators from 1.1 to 1.9. Furthermore, by changing constraint location, we succeeded in controlling directions of actuations of gel actuators. Finally, we demonstrate a mechanical stimulation device to stimulate living microorganisms by using the proposed method.