Microscale Robotic Wetware For Synthetic Biology
Autonomous fleets of small-scale robots have the potential to enhance operations or open entirely new avenues in domains ranging from medicine to manufacturing. For instance, microrobots could serve as vehicles to deliver therapeutics, assistants to manipulate cells in microbiological experiments, or agents to assemble microscale objects. In order to realize these applications, microrobots must locomote precisely, gather information from their environment, communicate to share information, and use that information to make decisions. Developing the key actuation, sensing, control, information processing, and associated fabrication methods, which underpin these high-level tasks, is still a significant challenge. In this dissertation, we present biohybrid approaches to microrobot design and fabrication in which organic and synthetic materials are synergistically combined to create a new class of microscale robotic systems, which we call "robotic wetware." By interfacing synthetic hardware and software with programmable living cells, we develop components and subsystems to enable more functional microrobots. We begin by designing and demonstrating biological actuation methods with an approach to simultaneously power and control groups of microstructures using active bacterial baths. We then introduce soft micro bio robots (SMBRs), the first microrobot platform which integrates on-board components derived from synthetic biology. We formulate a biocompatible fabrication method based on 3D printing and molding. We design SMBRs to harbor a suite of low-level functions including actuation and sensing, as well as sophisticated capabilities such as chemical or cellular delivery and biofilm remediation. We actuate SMBRs using applied magnetic fields, and use genetic engineering to design and construct living sensors, chemical actuators, and information processors which function on-board as additional elements of the feedback control loop. Similarly, we demonstrate microrobots as components of feedback control loops in biological circuits and show that robots carrying chemical actuators and biosensors can interrogate synthetic biological systems at a range of spatiotemporal scales. Finally, we develop strategies for multi-microrobot control and demonstrate teams of diamagnetically levitated milliscale robots equipped with manipulators such that they function as mobile assistants in microbiological experiments. These contributions constitute a suite of strategies for small-scale actuation, control, sensing, and information processing, and together form the enabling subsystems for autonomous biocompatible swarms.