In the present study, an ultrasensitive electrochemiluminescence (ECL) aptasensing assay for selective detection of Hg²⁺ was designed. In this electrochemiluminescence resonance energy transfer (ECL-RET) approach, Fe₃O₄@SiO₂/dendrimers/QDs exhibited amplified ECL emissions (switch “on” state) and with the hybridization between T-rich ssDNA(S₁) immobilized on the Fe₃O₄@SiO₂/dendrimers/QDs and AuNPs modified with complementary aptamer (AuNPs-S₂), the ECL of QDs nanocomposites was efficiently quenched (switch “off” state). In the presence of Hg²⁺ ions, formation of strong and stable T-Hg²⁺-T complex led to the release of the AuNPs-S₂ from double-stranded DNA(dsDNA) and the recovery of the ECL signal of QDs (second signal switch “on” state). Under optimal conditions, Hg²⁺ can be detected in a wide linear range from 20 aM to 2 µM with a very low detection limit of 2 aM. The proposed ECL aptasensor showed high selectivity for Hg²⁺ determination compared to other environmentally relevant metal ions at concentration ratio more than 1000 times. The aptasensor was used for detection Hg²⁺ ions from samples of tap waters, carp and saltwater fishes with satisfactory results. The aptasensor exhibited high sensitivity, wide linear response (11 orders of magnitude), excellent reproducibility and stability. The proposed aptasensor will be a promising candidate for facile and rapid determination of Hg^2＋in environmental and fishery samples.

在本研究中，设计了一种用于选择性检测Hg ²⁺的超灵敏电化学发光（ECL）适体测定。在这种电致发光共振能量转移（ECL-RET）方法中，Fe ₃ O ₄ @SiO ₂ /树枝状聚合物/ QDs表现出放大的ECL发射（切换为“ on”状态），并与固定在其上的富T ssDNA（S ₁）之间杂交。 Fe ₃ O ₄ @SiO ₂ /树枝状聚合物/ QDs和用互补适体（AuNPs-S ₂）修饰的AuNPs ，QDs纳米复合材料的ECL被有效地淬灭（“关闭”状态）。在Hg ²⁺存在下离子，强而稳定的T-Hg ²⁺ -T络合物的形成导致AuNPs-S ₂从双链DNA（dsDNA）释放和QDs的ECL信号恢复（第二信号开关“接通”状态） ）。在最佳条件下，可以在20 aM至2 µM的宽线性范围内检测到Hg ²⁺，而检测限仅为2 aM。与其他与环境相关的金属离子相比，拟议的ECL适体传感器在浓度比超过1000倍时，对Hg ^2+的测定具有很高的选择性。aptasensor用于检测Hg ²⁺从自来水，鲤鱼和咸鱼的样品中提取离子，结果令人满意。适体传感器显示出高灵敏度，宽线性响应（11个数量级），出色的重现性和稳定性。拟议的适体传感器将是用于环境和渔业样品中Hg ^2+的快速简便测定的有希望的候选者。