G-Quadruplex DNAzyme Molecular Beacon for Amplified Colorimetric Biosensing of Pseudostellaria heterophylla

Sensors

Zhenzhu Zheng²  Jing Han²  Wensheng Pang¹ 

[1] The College of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou 350122, China; E-Mail:;Institute of Drug Research, Fujian Academy of Chinese Medicine, Fuzhou 350003, China; E-Mails:

关键词: G-quadruplex DNAzyme;    molecular beacon;    colorimetric;    Pseudostellaria heterophylla;   

DOI  :  10.3390/s130101064

来源: mdpi

【 摘 要 】

With an internal transcribed spacer of 18 S, 5.8 S and 26 S nuclear ribosomal DNA (nrDNA ITS) as DNA marker, we report a colorimetric approach for authentication of Pseudostellaria heterophylla (PH) and its counterfeit species based on the differentiation of the nrDNA ITS sequence. The assay possesses an unlabelled G-quadruplex DNAzyme molecular beacon (MB) probe, employing complementary sequence as biorecognition element and 1:1:1:1 split G-quadruplex halves as reporter. In the absence of target DNA (T-DNA), the probe can shape intermolecular G-quadruplex structures capable of binding hemin to form G-quadruplex-hemin DNAzyme and catalyze the oxidation of ABTS²⁻ to blue-green ABTS^•− by H₂O₂. In the presence of T-DNA, T-DNA can hybridize with the complementary sequence to form a duplex structure, hindering the formation of the G-quadruplex structure and resulting in the loss of the catalytic activity. Consequently, a UV-Vis absorption signal decrease is observed in the ABTS²⁻-H₂O₂ system. The “turn-off” assay allows the detection of T-DNA from 1.0 × 10⁻⁹ to 3.0 × 10⁻⁷ mol·L⁻¹ (R² = 0.9906), with a low detection limit of 3.1 × 10⁻¹⁰ mol·L⁻¹. The present study provides a sensitive and selective method and may serve as a foundation of utilizing the DNAzyme MB sensor for identifying traditional Chinese medicines.

【 授权许可】

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