Development of An Ultra-Sensitive Microbial Sensor for Mercury Ions Detection

The development of synthetic biology has led to the widespread use of microbial sensors in areas such as environmental monitoring, food inspection, and healthcare. Compared to traditional detection methods, microbial sensors offer advantages such as low cost, high specificity, and ease of operation, while also providing early warnings of biological toxicity. These sensors typically use microorganisms like bacteria and yeast as host cells and employ transcription factors as key regulatory proteins to sense external signals and precisely control the transcription of target genes, allowing them to respond to environmental changes. This study developed an ultra-sensitive microbial sensor for mercury ions (Hg2+) based on the transcription factor MerR, which specifically bound to Hg2+ and regulated the expression of corresponding genes. It was found that the expression level of MerR was crucial for optimizing such sensors. Through continuous improvement, the Hg7 sensor was successfully constructed, which demonstrated outstanding sensing performance. The Hg7 sensor had a detection limit of 0.3 μg/L, a detection range of 0.3 to 30 μg/L, with excellent selectivity, high sensitivity, and rapid detection time (5 μg/L of Hg2+ could be detected within 15 min, and 1 μg/L of Hg2+ within 30 min). The Hg7 sensor′s efficacy was further validated by detecting Hg2+ content in toner and drinking water samples, showing its practical application potential. This study, centered on the exploration of mercury-ion biosensors, introduced a novel idea for the future advancement of analogous sensors.