▎ 摘　　要

Based on the different affinities of graphene oxide (GO) toward ssDNA and dsDNA, a fluorescence assay using split G-rich probes and magnetic GO (Fe3O4/GO) was developed for authentication of Pseudostellaria heterophylla based on the ITS sequences. In this assay, the probes mixed with Fe3O4/GO nanoparticles, hybridize with T-DNA for a double-stranded structure and then their G-rich sequences can fold into a G-quadruplex which combines hemin for DNAzyme. After magnetic separation, the DNAzyme supernatant can catalyze 2',7'-dichlorodihydrofluorescein diacetate (H(2)DCFDA) oxidation with H2O2 and release a fluorescence signal. Herein, the Fe3O4/GO nanoparticles play an important role in decreasing the background signal by absorbing the excess probes and hemin. This assay allows the analysis of T-DNA in the range of 1.0 x 10(-14) to 1.0 x 10(-7) mol L-1 with a low detection limit of 1.87 x 10(-15) mol L-1. In addition, this newly designed assay allows specific authentication of Pseudostellaria heterophylla from different provenances.