Jiangxi Provincial Key Laboratory of Functional Molecular Materials Chemistry, School of Chemistry and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou, 341000, PR China; State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, PR China.
Jiangxi Provincial Key Laboratory of Functional Molecular Materials Chemistry, School of Chemistry and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou, 341000, PR China.
Talanta. 2022 Nov 1;249:123646. doi: 10.1016/j.talanta.2022.123646. Epub 2022 Jun 1.
The foodborne pathogens have caused many life-threatening diseases. Herein, a new electrochemical platform was developed for detection, using 3D walking machine and enzyme-free toehold-mediated strand displacement. High-variable region of 16S rDNA fragment of Escherichia coli (E. coli) was used as the target to verify the approach. In presence of target, Exonuclease III (Exo III)-powered hairpin-loaded Au nanoparticles (hpDNA@AuNPs) was aroused, which emerged large amounts of 3D toehold-loaded AuNPs (toehold@AuNPs) walking machine. The "legs" of the walking machine hybridized with hairpin2 (HP2) tracks probe modified on surface of electrode and exposed toehold region of HP2 probe. The toehold-mediated strand displacement triggered rolling of AuNPs along the electrode, through the interaction of hairpin3-F (HP3-F) probe with toehold region of HP2 probe. Thus large amounts of F were closed to the electrode and led to significant current responses for E. coli detection. The method could continuously recycle low-concentration targets. Furthermore, due to the increase of "legs" and decrease of the derailment of leg DNA, which was beneficial to shorten detection time and amplify response. The detection limits (LOD) was 20 CFU/mL, the detection time was less than 1.5 h. This method was promising to be applied in early diagnosis of foodborne pathogen.
食源性病原体已导致许多危及生命的疾病。在此，我们开发了一种新的电化学生物传感平台，用于检测，该平台采用三维行走机器和无酶的触发引发链置换反应。以大肠杆菌（E. coli）高变区 16S rDNA 片段作为目标进行验证。在存在靶标时，外切核酸酶 III（Exo III）引发发夹负载的金纳米粒子（hpDNA@AuNPs），从而产生大量的 3D 触发负载的 AuNPs（toehold@AuNPs）行走机器。行走机器的“腿”与电极表面修饰的发夹 2（HP2）轨道探针杂交，并暴露出 HP2 探针的触发区域。触发引发链置换反应导致 AuNPs 沿着电极滚动，这是通过发夹 3-F（HP3-F）探针与 HP2 探针的触发区域之间的相互作用实现的。因此，大量的 F 被接近电极，导致对 E. coli 检测的显著电流响应。该方法可以连续循环低浓度的靶标。此外，由于“腿”的增加和腿 DNA 脱轨的减少，这有利于缩短检测时间和放大响应。检测限（LOD）为 20 CFU/mL，检测时间小于 1.5 h。该方法有望应用于食源性病原体的早期诊断。
