A protein-free, isothermal, self- amplified nucleic acid sensing system which was a G-quadruplex integrated hybridization chain reaction (GQ-HCR) system has been 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 7.5 nMssDNA or RNA by the colorimetric method and 4 nMssDNA 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.
Researchers from Chengdu Institute of Biology and Chengdu University of TCM cooperated to study this job. It received support from CAS (Hundreds of Talents Program), NSFC, Innovation Program of the CAS, Open Research Fund of State Key Laboratory Breeding Base of Systematic Research and Development and Utilization of Chinese Medicine Resource.
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