Browsing by Author "Wu, Beibei"

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    Exploiting the potential of spherical PAM antenna for enhanced CRISPR-Cas12a: a paradigm shift toward a universal amplification-free nucleic acid test platform
    (American Chemical Society, 2025-01-09) Dai, Jiahui; Wu, Beibei; Ai, Fengxiang; Yang, Zhugen; Lu, Yanyan; Zinian, Cai; Zeng, Kun; Zhang, Zhen
    The CRISPR-Cas12a system has shown tremendous potential for developing efficient biosensors. Albeit important, current CRISPR-Cas system-based diagnostic technologies (CRISPR-DX) highly rely on an additional preamplification procedure to obtain high sensitivity, inevitably leading to issues such as complicated assay workflow, cross-contamination, etc. Herein, a spherical protospacer-adjacent motif (PAM)-antenna-enhanced CRISPR-Cas12a system is fabricated for universal amplification-free nucleic acid detection with a detection limit of subfemtomolar. Meanwhile, the clinical detection capability of this sensor was further verified using gold-standard real-time quantitative polymerase chain reaction through Mycobacterium tuberculosis measurement, which demonstrated its good reliability for practical applications. Importantly, its excellent sensitivity is mainly ascribed to high efficiency of target search induced by a localized PAM-enriched microenvironment and improved catalytic activity of Cas12a (up to 4 folds). Our strategy provides some new insights for rapid and sensitive detection of nucleic acids in an amplification-free fashion.
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    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, Zhen
    Tetrahedral 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.