In situ monitoring of cytoplasmic precursor and mature microRNA using gold nanoparticle and graphene oxide composite probes

Anal Chim Acta. 2018 Aug 27;1021:129-139. doi: 10.1016/j.aca.2018.03.010. Epub 2018 Mar 19.


This study strategically fabricates a nucleic acid functionalized gold nanoparticle and graphene oxide composite probe (AuNP/GO probe) to achieve both the recognition and in situ monitoring of cytoplasmic target precursor microRNAs (pre-miRNAs) and mature microRNAs (miRNAs) in living cells. The pre-miRNA-21 detection with AuNP probes has a good linear range of 0-300 nM and a limit of detection (LOD) of 4.5 nM, whereas the GO probe has a linear relationship with mature miRNA-21 from 0.1 to 10 nM with a LOD of 1.74 nM. This assay was utilized to directly visualize the relative expression levels of pre- and mature forms of miRNA-21 and let-7a. The results suggested that the expression levels of precursor miRNAs remain constant in cancer cells and normal cells. However, the expression levels of mature miRNAs vary widely, demonstrating the "up-regulation" of miRNA-21 and "down-regulation" of let-7a in cancer cells in contrast to that in normal cells. The practicality of this strategy was verified by in situ monitoring changes in cytoplasmic pre-miRNA-21 and mature miRNA-21 in response to small-molecule inhibitors of miRNA-21.

Keywords: Fluorescence imaging; Mature microRNAs; Nanocomposite probe; Precursor microRNAs.

MeSH terms

  • Cell Line
  • Gold / chemistry*
  • Graphite / chemistry*
  • Humans
  • Metal Nanoparticles / chemistry*
  • MicroRNAs / analysis*
  • Molecular Probes / chemistry*
  • Oxides / chemistry*


  • MIRN21 microRNA, human
  • MicroRNAs
  • Molecular Probes
  • Oxides
  • Gold
  • Graphite