Living cell‐laden hydrogels: Unleashing the future of responsive biohybrid systems

Responsive biohybrid systems have the potential to overcome limitations of both natural and artificial machines in terms of efficiency, accuracy, and functionality. As functional units, living cells act as bricks for building biohybrid machines, where the extracellular matrix mimics hydrogels to act as ideal biological concrete. Combining living cells with hydrogels offers unique advantages in simulating human tissues or organs, which unleashes the future of biohybrid systems, and thus has attracted extensive attention. Herein, recent progress in cell‐laden hydrogel‐based responsive biohybrid systems is summarized to provide a basic understanding of how these systems are built from the bottom up and how to achieve the complex functions. This review focuses on advanced manufacturing technologies for responsive biohybrid systems, including laden cells in hydrogel matrices, three‐dimensional bioprinting, and microfluidic manufacturing. Subsequently, the innovative applications of these works, including actuators, sensors, and engineered functional materials, are presented, along with different triggering mechanisms that are highlighted. Finally, the current challenges and future opportunities in the field are addressed. This review provides a unique perspective and is hoped to inspire fields such as biohybrid technologies, soft robots, and tissue engineering.