Enzyme mimics have been developed for bioassay of nucleic acids, with some of them involving complicated labeling. Herein, we report a label-free bioassay for ultrasensitive electronic determination of microRNA at an ultralow concentration based on target-triggered long-range self-assembly DNA-based hybridization chain reaction (HCR) protocol coupled with bienzyme mimics synergistic catalysis strategy. In this work, a planar intercalation molecule, copper (II) complex, is applied for the first time as a small molecule enzyme mimic as well as intercalation molecule in microRNA biosensor for signal amplification. Fe₃O₄ nanozyme were used as a separate and enriched target under magnetic field, and also in combination with HCR protocol detected in 3,3’,5,5’-tetramethylbenzidine+hydrogen peroxide (TMB+H₂O₂) system to improve the sensitivity of the biosensor. Under optimal conditions, these strategies present good electrochemical behaviors for the detection of microRNA with a wide range from 100 aM to 100 nM and at relatively low detection limit of 33 aM This remarkable sensitivity can make this proposed approach a promising scheme for development of next-generation microRNA sensors without the need of enzyme labeling or fluorophore labeling.

已经开发了酶模拟物用于核酸的生物测定，其中一些涉及复杂的标记。在这里，我们报告了基于目标触发的远程自组装基于DNA的杂交链反应（HCR）协议结合双酶模拟协同催化策略的超低浓度的超低浓度microRNA的超灵敏电子测定的无标记生物测定法。在这项工作中，首次将平面插层分子铜（II）配合物用作小分子酶模拟物以及在microRNA生物传感器中用于信号放大的插层分子。铁₃ O ₄纳米酶被用作磁场下的一个单独的富集靶，并与在3,3'，5,5'-四甲基联苯胺+过氧化氢（TMB + H ₂ O ₂）系统中检测到的HCR方案结合使用，以提高灵敏度。生物传感器。在最佳条件下，这些策略呈现出良好的电化学行为，可用于检测范围从100 aM到100 nM且在相对较低的检测限33 aM的microRNA。这种非凡的灵敏度可以使这种拟议的方法成为开发下一分子的有前途的方案。无需酶标记或荧光团标记的新一代microRNA传感器。