Optimized genetic circuitry and reporters for sensitive whole-cell arsenic biosensors: advancing environmental monitoring.

The ubiquitous presence of arsenic pollution poses a significant threat to both ecosystem integrity and human health, necessitating the development of sensitive methods for arsenic detection. This study presents the development of innovative whole-cell biosensors that leverage the ArsR regulatory system within both naturally coupled and non-coupled genetic circuits, specifically optimized for detecting the highly toxic arsenic species (As(III)). These biosensors incorporate an indigoidine pigment as a reporting system and utilize the glycerol facilitator protein (GlpF) to enhance arsenic transport, offering a significant advantage over conventional detection methods by streamlining the detection process and eliminating the requirement for specialized instrumentation. Our findings reveal that the indigoidine-based biosensor, TOP10/pnK12-ABS-ind, in particular, exhibits an extensive linear detection range of 0.039 to 20 μM across various water matrices, effectively adhering to and exceeding the arsenic detection guidelines set by the World Health Organization and Chinese national standards. This research advances arsenic biosensing technology by developing a practical, cost-effective detection solution for arsenic in various aquatic settings. Compared to our previous work, this study demonstrates significant improvements in detection range and sensitivity while highlighting the importance of tailored genetic circuit design based on the reporter's choice.IMPORTANCEArsenic pollution poses a significant threat to global ecosystems and human health, with millions of people at risk of exposure through contaminated water sources. Detecting arsenic, especially in its highly toxic form (As(III)), is crucial for environmental monitoring and public health protection. However, conventional detection methods often require costly equipment and specialized expertise, limiting their feasibility in resource-limited regions. Our study addresses this challenge by developing whole-cell biosensors that leverage natural genetic circuits and a novel indigoidine pigment reporter. These biosensors offer a practical, cost-effective, and portable solution for arsenic detection, streamlining the process and eliminating the need for complex instrumentation. By enabling real-time monitoring and on-site analysis, our biosensors have the potential to significantly enhance environmental monitoring capabilities, facilitate timely remediation efforts, and safeguard public health in areas affected by arsenic contamination.