Label-free DNAzyme assays for dually amplified and one-pot detection of lead pollution.

Lead pollution in water and soil often transfers to food, advocating tools for on-site detection of lead pollution to ensure both environmental and food safety. We proposed a label-free, dually amplified and homogeneous DNAzyme assay for sensitive and one-pot detection of lead pollution. Instead of using chemically modified DNA substrate, a structure-response digestion process was introduced to monitor Pb presence-induced cleavage process of unlabeled substrate, further amplifying the response signals and eliminating the use of labeled DNA probes. The DNAzyme assay allowed to detect Pb as low as 0.12 nM and endued a dynamic range from 0.1 nM to 30 nM. In addition, it can specifically identify Pb among other metal ions. We demonstrated that the DNAzyme assay can precisely detect Pb in tap water, milk and fish. Thus, the DNAzyme assay is promising for on-site monitoring lead pollution risk and ensuring environmental and food safety.