PROJECT SUMMARY Synthetic biologists develop tools and approaches to endow microorganisms with novel attributes and behaviors, as well as the ability to synthesize novel products. There have been few reports, however, wherein bacteria serve as components of devices created to transmit biological information to and from electronic devices. Information flow between biological systems and electronic devices is complicated by the fact that most of biological function is mediated by molecular or ionic cues, while devices are programmed by electrons and photons. Technologies that have facilitated the bio/device intersection have changed our lives (e.g., EKG). Our objective is to rewire bacteria to serve as information translators and to do this in a way that facilitates understanding of human health. The human gastrointestinal microbiome, often viewed as a complex organ itself, influences homeostasis and is implicated in many human diseases. GI tract geometry is complex and its microenvironments are widely varied. pH and oxygen levels exist from the most acidic to neutral, and from completely anaerobic to oxygen saturation levels, respectively. There are few methodologies that enable resolution of its signaling, cell growth, and chemical environments even at the macro length scale. In the last several years however, researchers have developed micro and meso systems for interrogating GI tract biology. Capsular endoscopy has enabled first-of-kind remote imaging. At the microscale, organ or animal-on-a-chip methodologies provide first-of-their kind access to biological function in user-controlled conditions. Both methodologies will open new avenues for diagnosis and treatment of human disease. Both methodologies, however, lack the ability to interrogate and modulate biological signaling at cellular length scales and in real time. The proposed studies will enlist synthetic biology to create `smart' hydrogels for interrogating molecular space. The innovation of this proposed study is the development of `biological lithography', where polyelectrolyte polysaccharides, doped with redox responsive catechols, will be layered with engineered cells for an expanded repertoire of molecular recognition and information transfer. Importantly, fabrication methodologies are simple and biologically benign so that these sensing materials can be assembled in situ in minutes and with no added mechanical equipment. To date, in vitro devices at both micro and meso scale do not provide molecular information at the length and time scales of the cells they interrogate. The significance of this work is its complementarity to animal-on-a-chip systems, capsular endoscopy devices, and other methodologies that have great promise for advancing diagnosis and treatment of disease but that lack access to molecular cues and information transfer.

PROJECT NARRATIVE The goal of this project is to create and exploit rewired cells as mediators of information flow, to use bacterial cells to interrogate molecular cues in biological environments and transmit information in a manner that enables bidirectional connection with electronics. The biological testbed is a “gut-on-a-chip” system that recapitulates GI tract biology. If successful, new molecular insight will be obtained from animal-on-a-chip devices, ingestible diagnostic devices, and endoscopic devices that hold great promise for drug discovery and the diagnosis and treatment of disease.