Chemically responsive protein-photoresist hybrid actuator

We report the multiphoton fabrication of hybrid microstructures of photoresist and chemically responsive protein hydrogel for microactuation, such as a lever and a rotary stepper. By two-step direct laser writing (DLW) technology, we combine chemically responsive protein hydrogel with mechanical robust photoresist into pH-responsive hybrid actuators that contain only biocompatible materials. The fabrication can be performed separately, without adding to the complexity of device fabrication. We observe micrometer-range motion of the photoresist components. These microactuators may also serve as a pH- or salt-concentration-sensor that measure and interact with their environment by their motion as immediate feedback.