A Split G-Quadruplex and Graphene Oxide-Based Low-Background Platform for Fluorescence Authentication of Pseudostellaria heterophylla

A label-free split G-quadruplex and graphene oxide (GO)-based fluorescence platform has been designed to distinguishPseudostellaria heterophylla(PH) from its adulterants based on the differences in their nrDNA ITS sequences. Herein, GO has been first introduced to capture G-rich probes with 2:2 split mode and then decrease the background signal. As T-DNA exists, the probes leave the GO surface to form double-stranded structures followed by the formation of the overhanging G-rich sequence into a G-quadruplex structure, which combines quinaldine red specifically to produce a strong fluorescence signal. In addition, this strategy allows detection of T-DNA in a wide range of concentrations from 1.0 × 10−8to 2.0 × 10−6mol·L−1with a detection limit of 7.8 × 10−9mol·L−1. We hope that the split G-quadruplex/GO platform can be utilized to further develop gene identification sensors in Traditional Chinese Medicine or other analysis areas.Keywords:split G-quadruplex;graphene oxide;fluorescence;Pseudostellaria heterophylla