Programmable Microparticle Scaffolds for Enhanced Diagnostic Devices

Microrobotics is an emerging discipline with the potential to radically affect fields ranging from medicine to environmental stewardship. Already, there have been remarkable breakthroughs; small scale robots have been made that can selectively traverse the gastrointestinal tract, and others have been built that can fly in a manner inspired from bees. However, there are still significant challenges in microrobotics, and it remains difficult to engineer reliable power sources, actuators, and sensors to create robust, modular designs at the microscale. The miniaturization of the robotic system makes design and efficiency of these components particularly difficult. However, biological systems demonstrate the key features of robotics – sensing, actuation, processing – and are remarkably complex at the microscale. As such, many researchers have turned to biology for inspiration and living robotic components. In our laboratory we have engineered an Escherichia coli (E. coli) capable of producing surface display proteins to either anchor the cells, bind to functionalized nanoparticles, or capture small molecules from the environment, all complex actuation features. Additionally, we have created a processing unit that can create signals based on biological components, yet is non-living. This thesis focuses on the characterization of the surface display E. Coli system and the creation of programmable microparticle scaffolds that may be controlled by biological circuitry. In particular, by leveraging the strong interaction between biotin and streptavidin, I have created programmable microparticle scaffolds capable of attenuating the intensity of a fluorescent response in response to perturbations in the local environmental conditions. We believe this is an excellent enabling technology to facilitate the creation of complex behaviors at the microscale and can be used as a processing unit for simple decision making on microrobots. We foresee this technology impacting disciplines from medical microrobotics to environmental sensing and remediation. Programmable Microparticle Scaffolds for Enhanced Diagnostic Devices MaryJoe Kathryn Rice General Audience Abstract Robots have integrated into industries ranging from car manufacturing to in-hospital transportation. However, recently there has become a new desire for robotics at a smaller scale, for use in fields ranging from medicine to agriculture. For example, how awesome would it be if we had small robots traveling through our bloodstream giving therapeutic drugs as needed or selectively killing tumor cells? This is the dream and goal of many research labs currently. However, when we try to design these tiny robots, we find that we are unable to use many of the normal components that are seen when looking at conventional electronics, AAA batteries as power sources for example. To build upon the example, how would a tiny robot in the body power itself or know when it has reached a cancerous tumor? We propose that the problem of decreased space can be solved by using biological components, like bacteria cells which already live at a microscopic scale, to power these robots and help them sense their surroundings. The work discussed in this thesis involves the design of biological sensors and processing units. We have proven that by engineering the DNA of bacteria cells, using the tools of synthetic biology, we are able to use the outside of the cell (cell’s surface) to sense components in the environment. We hope that the findings discussed in this thesis will serve as the ground work for integrating living cells and robotics for future applications ranging from medicine to environmental remediation.