Biological Sentinel: An Efficient Engineered Bacterial System for Monitoring and Tracing Regulated Hazardous Chemicals.

Monitoring and tracing of regulated hazardous chemicals is a public security issue of global concern. However, accurately recording historical exposure remains challenging. Here, we designed a Biological Sentinel System (BOSS) for in situ and long-term monitoring of hazardous chemical exposure using a chemical-induced base-editing system that activates antibiotic resistance screening, producing an obvious colorimetric signal. Exposure events can be written into an inheritable genomic DNA sequence, which can be read using gene sequencing. As a proof of concept, we demonstrated the accurate detection of cocaine and 2,4-dinitrotoluene using BOSS under simulated application scenarios. In addition, we integrated alternative biosensors to illustrate the modularity and extensibility of this monitoring platform. This work provides a promising paradigm for developing engineered microorganisms as an alternative to electronic monitors for regulated hazardous chemicals.