CRISPR-Hg: Rapid and visual detection of Hg²⁺ based on PCR coupled with CRISPR/Cas12a

Mercury (Hg) is a notorious toxic heavy metal, causing neurotoxicity and liver damage, posing grave threats to human health and environmental safety. There is an urgent imperative for developing novel Hg²⁺ detection methods. In this work, we developed a CRISPR-based method for Hg²⁺ detection named CRISPR-Hg. A CRISPR/Cas12a system was employed and could be activated by the PCR product, generating fluorescence signals based on the trans-cleavage activity. CRISPR-Hg exhibited remarkable selectivity and specificity, achieving a detection limit of 10 pM and minimal interference with background signals. This approach has been successfully applied to detect Hg²⁺ in real samples, including water, soil, and mushroom. Ulteriorly, a portable device was devised to streamline the readout of fluorescence signals by a smartphone within 30 min. We offer an affordable, highly selective and visually interpretable method for Hg²⁺ detection, with the potential for broad application in Hg²⁺ monitoring for food safety and public health.