MicroRNAs are potential biomarkers related to many diseases and life nature, including ageing, cancers, cell senescence and so on. It is valuable to establish sensitive assays for monitoring the low-abundance intracellular miRNAs, which would contribute to the early prediction of the tumor risk and cardiovascular disease. Herein, we introduce two novel miRNA sensing methods focusing on sensitivity and specificity, one was an oriented gold nanocross-decorated gold nanorod probe with “OFF-enhanced ON” fluorescence switching based on fluorescence resonance energy transfer and surface enhanced fluorescence principle, the other was a new-type comet-like gold nanoflower @ graphene quantum dots probe based on the toehold-mediated DNA circuit with “OFF-ON” signal amplification. The outstanding nanoprobe could make up the disadvantage in traditional sensing method with insufficient low signal-to-background, and gave good linear responses. Furthermore, the nanoprobe was used to dynamically monitor the expression of intracellular up-regulated miRNA from the HepG2 and H9C2 cells stimulated by AFB1 and TGF-β1, and the experimental results showed that the newly probe not only could be used to quantitively track and image miRNA oncogene in vitro, but also could be used in vivo test, and the result further confirmed that the comet-like nanoprobe existed good specificity in differentiating the young and ageing heart, which could be readily extended to other diseases with identifiable miRNA signatures at low levels of expression.

Ultrasensitive "OFF-ON" fluorescence signal strategy for sensing and imaging microRNAs in vitro and in vivo based on oriented gold nanoconjugates

256th National Meeting (2018)

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