Browsing by Author "Zhang, Zhen"
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Item Open Access Efficient DNA walker guided by ordered cruciform-shaped DNA track for ultrasensitive and rapid electrochemical detection of lead ion(Elsevier, 2024-03-20) Zhu, Nuanfei; Wang, Kaixuan; Xiong, Dinghui; Xiao, Jiaxuan; Deng, Yibin; Yang, Zhugen; Zhang, ZhenThe rational design of DNA tracks is an effective pathway to guide the autonomous movement and high-efficiency recognition in DNA walkers, showing outstanding advantages for the cascade signal amplification of electrochemical biosensors. However, the uncontrolled distance between two adjacent tracks on the electrode could increase the risk of derailment and interruption of the reaction. Hence, a novel four-way balanced cruciform-shaped DNA track (C-DNT) was designed as a structured pathway to improve the effectiveness and stability of the reaction in DNA walkers. In this work, two kinds of cruciform-shaped DNA were interconnected as a robust structure that could avoid the invalid movement of the designed DNA walker on the electrode. When hairpin H2 was introduced onto the electrode, the strand displacement reaction (SDR) effectively triggered movements of the DNA walker along the cruciform-shaped track while leaving ferrocene (Fc) on the electrode, leading to a significant enhancement of the electrochemical signal. This design enabled the walker to move in an excellent organized and controllable manner, thus enhancing the reaction speed and walking efficiency. Compared to other walkers moving on random tracks, the reaction time of the C-DNT-based DNA walker could be reduced to 20 min. Lead ion (Pb2+) was used as a model target to evaluate the analytical performance of this biosensor, which exhibited a low detection limit of 0.033 pM along with a wide detection ranging from 0.1 pM to 500 nM. This strategy presented a novel concept for designing a high-performance DNA walker-based sensing platform for the detection of contaminants.Item Embargo Poly-adenine-mediated tetrahedral DNA nanostructure with multiple target-recognition sites for ultrasensitive and rapid electrochemical detection of Aflatoxin B1(Elsevier, 2023-10-26) Wang, Kaixuan; Zhu, Nuanfei; Li, Yumo; Zhang, Hu; Wu, Beibei; Cui, Jian; Tang, Jun; Yang, Zhugen; Zhu, Fang; Zhang, ZhenTetrahedral DNA nanostructures (TDNs) are widely used in the development of electrochemical biosensors due to their structural stability, programmability, and strong interfacial orderliness. However, the complex modifications on the electrode and the single vertex target recognition of the TDNs limit their applications in electrochemical biosensing. Herein, we developed a universal detection system based on a novel polyadenine-based tetrahedral DNA nanostructure (ATDN) using Aflatoxin B1 (AFB1) as the model target for analysis. In the absence of target AFB1, the signal probes (SP) modified with ferrocene would be anchored by five aptamers on ATDN. The target capture by aptamers led to a release of SP from the electrode surface, resulting in a significant reduction of the electrochemical signal. This new nanostructure was not only dispensed with multi-step electrode modifications and strong mechanical rigidity but also had five modification sites which enhanced the detection sensitivity for the target. As a result, this biosensor shows good analytical performance in the linear range of 1 fg mL−1 to 1 ng mL−1, exhibiting a low detection limit of 0.33 fg mL−1. Satisfactory accuracy has also been demonstrated through good recoveries (95.2%–98.9%). The proposed new tetrahedral DNA nanostructure can provide a more rapid and sensitive alternative to previous electrochemical sensors based on the conventional TDN. Since DNA sequences can be designed flexibly, the sensing platform in this strategy can be extended to detect various targets in different fields.