A close-looped DNAzyme walker with an available catalytic domain for electrochemiluminescent detection of acetamiprid

Traditional DNA walkers face enormous challenges due to limited biostability and reaction kinetics. Herein, we designed a self-driven close-looped DNAzyme walker (cl-DW) with high structural biostability and catalytic activity that enabled rapid electrochemiluminescence (ECL) detection of pesticide residue acetamiprid. Specifically, cl-DW exhibited increasing ability to resist nuclease degradation with a 570-fold longer half-degradation time than that of the single-stranded DNAzyme walker (ss-DW) due to the protected DNA terminal. Furthermore, cl-DW achieved high catalytic activity with a 4.3-fold faster reaction kinetic than that of ss-DW due to the circularized nanostructure of an available catalytic domain. Consequently, we utilized cl-DW as a signal amplifier and tin-based sulfide (SnS2) nanoflowers as ECL emitters to construct an ECL aptasensor, which realized the sensitive detection of acetamiprid with a limit of detection of 0.85 nM. This work provides a reliable approach to exploring DNA walkers with high catalytic activity and better biostability for molecular monitoring. •An electrochemiluminescence aptasensor was designed for acetamiprid detection.•Spatial folding effect enhanced catalytic activity of close-looped DNAzyme walker.•Close-looped DNAzyme walker had improved structural biostability.•This method had satisfactory results for practical application of small molecule.