Engineered DNA molecular machine for ultrasensitive detection of environmental lead pollution

Dynamic monitoring of environmental Pb²⁺ is of utmost importance for food safety and personal well-being. Herein, we report a novel, rapid, and practical fluorescence detection platform for Pb²⁺. The platform comprises two essential components: an engineered DNAzyme probe (EDP) and a responsive functionalized probe (RFP). The EDP demonstrates specific recognition of Pb²⁺ and the subsequent release of free DNA fragments. The released DNA fragments are then captured using the RFP to form DNA complexes, which undergo multiple cascade amplification reactions involving polymerases and nickases, resulting in the generation of a large number of fluorescence signals. These signals can detect Pb²⁺ at concentrations as low as 0.114 nmol/L, with a dynamic range spanning from 0.1 nmol/L to 50 nmol/L. Moreover, the platform exhibits excellent sensitivity and selectivity for Pb²⁺ detection. To further validate its effectiveness, we successfully quantitatively detected lead contamination in water from Chaohu Lake, and the results aligned closely with those obtained using inductively coupled plasma-mass spectrometry (ICP-MS). Moreover, this platform is suitable for detecting Pb²⁺ in seawater, soil, and fish samples. These findings confirm the suitability of the current detection platform for the dynamic assessment of Pb contamination in ecological environments, thereby contributing to environmental and food safety.