Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, MOE, Shandong Key Laboratory of Biochemical Analysis, Key Laboratory of Analytical Chemistry for Life Science in Universities of Shandong, College of Chemistry and Molecular Engineering , Qingdao University of Science and Technology , Qingdao 266042 , People's Republic of China.
Anal Chem. 2019 Mar 5;91(5):3546-3554. doi: 10.1021/acs.analchem.8b05362. Epub 2019 Feb 15.
Herein, a new multifunctional DNA nanotube (DNANT) was self-assembled and used to load Ru(phen) and methylene blue (MB) as amplified signal probes for versatile electrochemiluminescence (ECL) and electrochemical (EC) "on-off" assays of Dam methylase (MTase) and aflatoxin B1 (AFB1). The DNA nanotube as a carrier could immobilize numerous MB or Ru(phen) species in the double-stranded DNA (dsDNA) to significantly amplify signals, which enabled highly sensitive ECL and electrochemical detection of dual targets. The target Dam MTase first catalyzed the methylation of hairpin DNA (H), and then the methylated DNA was cleaved by endonuclease DpnI to expose a single-strand DNA. After the Ru(phen)-DNANT or MB-DNANT signal probes were assembled to the electrode by hybridization, remarkable "signal on" states for amplified ECL or EC assays of MTase were obtained. Furthermore, in the presence of the target AFB1, the structure of DNANTs collapsed due to the specific binding of AFB1 to aptamer S2 in NTs, which led to the release of signal probes (Ru(phen) or MB) from the electrode to achieve "signal off" state for dual detection of AFB1. Taking advantage of the multifunctional DNANT amplification signal probes, the versatile biosensors showed good analytical performance with very wide linear ranges (0.001-100 U mL and 0.0001-100 ng mL for MTase and AFB1 assay by DPV) and lower detection limits (2.1 × 10 U mL and 0.018 pg mL for MTase and AFB1 by DPV). This is the first time that ECL and EC "on-off" methods have been achieved separately for dual target assays, which opens a new avenue of DNANT-based signal amplification strategyies for the versatile design of biosensors in various biological detections.
在此，自组装了一种新型多功能 DNA 纳米管 (DNANT)，并将其用于负载 Ru(phen) 和亚甲基蓝 (MB) 作为扩增信号探针，用于多功能电致化学发光 (ECL) 和电化学 (EC) “开-关”测定 Dam 甲基化酶 (MTase) 和黄曲霉毒素 B1 (AFB1)。作为载体的 DNA 纳米管可以在双链 DNA (dsDNA) 中固定大量的 MB 或 Ru(phen) 物种，从而显著放大信号，实现对双靶标的高灵敏度 ECL 和电化学检测。靶标 Dam MTase 首先催化发夹 DNA (H) 的甲基化，然后内切酶 DpnI 切割甲基化 DNA 以暴露单链 DNA。在 Ru(phen)-DNANT 或 MB-DNANT 信号探针通过杂交组装到电极上之后，得到了用于 MTase 扩增 ECL 或 EC 测定的显著“信号开启”状态。此外，在存在靶标 AFB1 的情况下，由于 AFB1 与 NTs 中的适体 S2 特异性结合，DNANTs 的结构坍塌，导致信号探针 (Ru(phen) 或 MB) 从电极上释放出来，从而实现了 AFB1 的双检测的“信号关闭”状态。利用多功能 DNA 纳米管扩增信号探针，该多功能生物传感器表现出良好的分析性能，具有非常宽的线性范围（0.001-100 U mL 和 0.0001-100 ng mL 用于 MTase 和 AFB1 的 DPV 测定）和较低的检测限（2.1 × 10 U mL 和 0.018 pg mL 用于 MTase 和 AFB1 的 DPV）。这是首次分别为双靶标测定实现 ECL 和 EC“开-关”方法，为基于 DNA 纳米管的信号放大策略在各种生物检测中的多功能生物传感器设计开辟了新途径。
