title: Toehold-mediated nonenzymatic amplification circuit on graphene oxide fluorescence switching platform for sensitive and homogeneous microRNA detection.
abstract: A novel graphene oxide (GO) fluorescence switch-based homogenous system has been developed to solve two problems that are commonly encountered in conventional GO-based biosensors. First, with the assistance of toehold-mediated nonenzymatic amplification (TMNA), the sensitivity of this system greatly surpasses that of previously described GO-based biosensors, which are always limited to the nM range due to the lack of efficient signal amplification. Second, without enzymatic participation in amplification, the unreliability of detection resulting from nonspecific desorption of DNA probes on the GO surface by enzymatic protein can be avoided. Moreover, the interaction mechanism of the double-stranded TMNA products contains several single-stranded toeholds at two ends and GO has also been explored with combinations of atomic force microscopy imaging, zeta potential detection, and fluorescence assays. It has been shown that the hybrids can be anchored to the surface of GO through the end with more unpaired bases, and that the other end, which has weaker interaction with GO, can escape GO adsorption due to the robustness of the central dsDNA structures. We verified this GO fluorescence switch-based detection system by detecting microRNA 21, an overexpressed non-encoding gene in a variety of malignant cells. Rational design of the probes allowed the isothermal nonenzymatic reaction to achieve more than 100-fold amplification efficiency. The detection results showed that our strategy has a detection limit of 10 pM and a detection range of four orders of magnitude.
authors: MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, PR China.
authors: Ru
authors: R
authors: Huang
authors: MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, PR China.
authors: Yuhui
authors: Y
authors: Liao
authors: MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, PR China. Electronic address: zhouxm@scnu.edu.cn.
authors: Xiaoming
authors: X
authors: Zhou
authors: MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, PR China. Electronic address: xingda@scnu.edu.cn.
authors: Da
authors: D
authors: Xing
mesh_terms: D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D057230:Limit of Detection; D035683:MicroRNAs / Q000032:analysis*; D010087:Oxides / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013499:Surface Properties
chemical_list: D005456:Fluorescent Dyes; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D010087:Oxides; D006108:Graphite
keywords: Fluorescence switch; Graphene oxide; Hairpin probe; MicroRNA detection; Nonenzymatic amplification