Recent progress in engineering functional biohybrid robots actuated by living cells.

Living cells are highly scalable biological actuators found in nature, and they are efficient technological solutions to actuate robotic systems. Recent advancements in biofabrication and tissue engineering have bridged the gap to interface muscle cells with artificial technology. In this review, we summarize the recent progress in engineering the attributes of individual components for the development of fully functional biohybrid robots. First, we address the fabrication of biological actuators for biohybrid robots with muscle cells and tissues, including cardiomyocytes, skeletal muscles, insect tissues, and neuromuscular tissues, in well-organized pattern of 2D sheets and 3D constructs. Next, we discuss the performance of biohybrid robots for various biomimetic tasks such as swimming, walking, gripping, and pumping. Finally, the challenges and future directions in the development of biohybrid robots are described from different viewpoints of living material engineering, multiscale modeling, 3D printing for manufacturing, and multifunctional robotic system development.