Detection of microRNA in clinical tumor samples by isothermal enzyme-free amplification and label-free graphene oxide-based SYBR Green I fluorescence platform.

MicroRNAs (miRNAs) are a kind of small molecules that involve in many important life activities. They have higher expression levels in many kinds of cancers. In this study, we developed an isothermal enzyme-free amplification (EFA) and label-free graphene oxide (GO)-based SYBR Green I fluorescence platform for detection of miRNA. MiRNA-21 was used as an example to demonstrate the feasibility of the method. Results show that the sensitivity of miRNA-21 is 1pM, and the linearity range is from 1pM to 1nM. The method can specifically discriminate miRNA-21 from miRNA-210 and miRNA-214. Three tumor cell lines of A549, HepG2 and MCF7 were detected by the method. The sensitivities of them were 10(2) cells, 10(3) cells and 10(3) cells respectively. Clinical tumor samples were also tested by this method, and 29 of 40 samples gave out positive signals. The method holds great promise in miRNA detection due to its convenience, rapidness, inexpensive and specificity.