MicroRNAs (miRNAs) are 19-25 nt non-coding RNAs that are processed from longer endogenous hairpin transcript with the enzyme dicer.Several hundred miRNAs are encoded in the human genome and dozens have now been shown to regulate a diverse variety of cellular processes, both in normal physiology and in disease.Methods for sensitive and multiplex detection of miRNAs are of great significance to miRNA discovery, study and clinical diagnosis.1 In this work, combining graphene oxide (GO)-protected DNA probes2 and cyclic enzymatic amplification method (CEAM) we have reported previously3, we developed a new platform for simple, sensitive and multiplex detection of any miRNA in complex biological samples.This method relied on DNase Ⅰ and a single-labeled DNA fluorescent probe adsorbed on graphene.In the absence of miRNA, different dye-labeled probes were in a flexible single strand state and adsorbed on the graphene and, as a result, the probes were non-fluorescent.Upon the addition of specific miRNA, the binding between the probes and target molecule altered the conformation of the probe, and disturbed the interaction between the probe and graphene, resulting in the release of the probes from GO and consequently restoration of dye fluorescence.The DNA/RNA hybrid double-strand de-adsorpted from the GO surface immediately became a substrate for DNase Ⅰ and led to digestion of the probe, subsequently releasing the miRNA to bind to another probe on GO to initiate next round of cleavage.This cyclic reaction repeated again and again until all the related-probes were consumed and all fluorophores lighted up, resulting in significant fluorescent signal amplification.By this method, we developed a signal amplification detection of miRNA with detection limit of 1pM in complex biological samples and achieved specific and multiplex miRNA detection.