Sentinel Microbes: Pathogen Detection Abstract / Project Overview The Sentinel Microbes project focuses on the development of a whole-cell bacterial biosensor based on Escherichia coli for the non-invasive detection of enteric pathogens. This system utilizes a synthetic gene circuit governed by the LuxR-AHL (Acyl-homoserine lactone) quorum sensing mechanism. By detecting exogenous AHL signals—a universal “language” used by Gram-negative pathogens like Salmonella typhimurium—the engineered microbes act as an early warning system, reporting the presence of infection through the expression of Superfolder Green Fluorescent Protein (sfGFP).