The ability to actively change shape is essential to all kinds of living organisms. For example, the Venus flytrap closes its leaves in less than seconds to efficiently catch flies, and pine cones open their scales when the environment is dry to release their seeds. Inspired by such phenomena, numerous studies have aimed to develop artificial smart materials which can undergo shape transformations under the action of an external stimulus. Among the various classes of shape-changing materials, hydrogels  are particularly attractive because of the potential for significant changes in volume under diverse external stimuli, and the potential for programmable complex shape changes. The interesting properties of hydrogels make them candidates for diverse applications in many fields, such as in soft robotics, artificial muscles, three-dimensional (3D) cell culture and drug or cell delivery devices. In this project we explore an innovative approach to spatially varying properties of hydrogels so that they undergo rapid and reversible shape changes on exposure to external stimuli. Responsible scientist: Andrew Whittaker