Wu et al. (2026) develop a whole-cell biosensor for the detection of methylmercury (MeHg) in environmental water samples. The biosensor exploits a genetically engineered microbial cell line expressing a MeHg-responsive regulatory element coupled to a reporter system, enabling sensitive and specific detection of organic mercury species distinct from inorganic Hg2+.
Key numbers
Limit of detection (LOD): 0.04 nM methylmercury. The LOD in mass units is approximately 0.008 µg/L (8 ng/L) given MeHg molecular weight ~217 g/mol.
Validated matrices: river water and lake water (environmental water). Food matrices were not tested. The selectivity for MeHg over inorganic Hg2+ is a key feature of this platform.
Methods (brief)
Whole-cell biosensor based on engineered microorganism. MeHg-responsive genetic circuit. Fluorescence or luminescence readout. Not a validated food-matrix method; designed for environmental water monitoring. The sub-0.1 nM LOD is competitive with instrumental methods for field deployment.
Implications
Testing: Demonstrates advances in biosensor approaches to MeHg speciation. Currently positioned for environmental water monitoring rather than food matrices. The iAs/MeHg speciation distinction is important for food testing (ICP-MS-based methods remain the standard for regulated food matrices).