Multiple DNA cycle amplification for highly efficient detection of mercury pollution in food

Mercury ion (Hg²⁺), a highly toxic metal pollutant, is widely found in the environment and can enter the human body through the food chain, causing various health issues. Sensitive and accurate methods for monitoring Hg²⁺ are highly desirable for ensuring food safety. Herein, we propose a self-sustainable multiple amplification system (MAS) for Hg²⁺ determination through the reciprocal activation between catalytic hairpin assembly (CHA) and rolling circle amplification (RCA). The thymine-encoded recognition element specifically recognizes Hg²⁺, triggering the exposure of the initiator. The initiator then motivates the mutual activation of CHA and RCA to accelerate the production of an exponentially amplified signal. The MAS method achieved a low detection limit of 11 pM. Due to its reliable target recognition and robust amplification efficiency, the MAS circuit facilitated the highly efficient and accurate analysis of low-abundance Hg²⁺ in milk and snakehead samples, thus providing a potentially new tool for food safety control.