Amplified detection of nucleic acid by G-quadruplex based hybridization chain reaction

• Published in: Biosensors & bioelectronics 2012-10, Vol.38 (1), p.258-263
• Main Authors: Dong, Juan, Cui, Xin, Deng, Yun, Tang, Zhuo
• Format: Article
• Language: English
• Subjects: Base Sequence; Biological and medical sciences; Biotechnology; Colorimetry - methods; Fluorometry - methods; Fundamental and applied biological sciences. Psychology; G-quadruplex; G-Quadruplexes; GQ-HCR; Hybridization chain reaction; Molecular Sequence Data; Nucleic Acid Amplification Techniques - methods; Nucleic Acid Hybridization - methods; Nucleic Acids - analysis; Nucleic Acids - genetics; PCR+GQ-HCR; Polymerase Chain Reaction - methods; Sensitivity and Specificity; Tyramine - chemistry; Visual chip
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2012.05.042

A protein-free, isothermal, self-amplified nucleic acid sensing system which was a G-quadruplex integrated hybridization chain reaction (GQ-HCR) system was developed. The G-quadruplex was closed two-thirds in the loop and one-third in the stem of one of the GQ-HCR hairpin probes. In the absence of the target molecule, the GQ-HCR probes stayed as inactive meta-stable hairpin structures and the G-quadruplex was inert. Reversely, the GQ-HCR probes could be cross-opened to start a hybridization chain reaction and the closed G-quadruplex could be released to be free when the GQ-HCR probes came across the target molecule. The GQ-HCR nucleic acid sensing system could detect as low as 7.5nM ssDNA or RNA by the colorimetric method and 4nM ssDNA by the fluorometric method. Less than 10 copies of dsDNA template could also be detected when PCR was combined with the GQ-HCR system (PCR+GQ-HCR). Because of these advantages, the GQ-HCR system was also studied for application in visual chip detection to obtain a satisfactory repeatable and specific result. ► Protein-free, isothermal, self-amplified nucleic acid sensing system GQ-HCR via the integration of intact G-Quadruplex and HCR for the colorimetric or fluorimetric detection of single-stranded DNA or RNA. ► In order to detect double stranded DNA and get much better detection sensitivity, we improved the detection system further through the combination of PCR with GQ-HCR. ► GQ-HCR system is an ideal platform to develop visual-chip based nucleic acid detection.