3D printed protein-based robotic structures actuated by molecular motor-based cortices

Upscaling motor protein activity to perform work in man-made devices has long been an ambitious goal in bio-nanotechnology. The use of hierarchical motor assemblies, as realized in sarcomeres, has so far been complicated by the challenges of arranging sufficiently high numbers of motor proteins with nanoscopic precision. Here we suggest an alternative approach based on actomyosin cortex-like force production, allowing low complexity motor arrangements in a contractile meshwork that can be locally activated by ATP. The design is reminiscent of a motorized exoskeleton coating and thereby actuating soft protein-based polymer structures from the outside. This readily supports the connection and assembly of micro-3D printed modules into larger structures, thereby scaling up mechanical work. We provide an analytical model of force production in these systems and demonstrate the design flexibility by 3D printed units performing complex mechanical tasks, such as micro-arms and hands that perform sign language and wave.