A facile biosynthesis strategy of plasmid DNA-derived nanowires for readable microRNA logic operations

Multiple microRNA (miRNA) logical assays have attracted wide attention recently, which can be applied to mimic and reveal cellular events at the molecular level. However, it remains challenging to develop labeling- and amplification-free approaches to perform logical functions with low levels of miRNA molecules. Herein, we proposed a strategy for miRNA logic operations using plasmid DNA-derived nanowires produced from a facile biosynthesis method. First, let-7d was chosen as the model target of the plasmid DNA-derived nanowire strategy, which showed good selectivity and a response sensitivity of as low as the femtomolar level. The operations of the miRNA logic gates proved the programmability of the constructed plasmid DNA-derived nanowire system for two inputs (let-7d and miR-21). Finally, three pairs of DNA nanowires were combined together to demonstrate the availability of this strategy in parallel multiple miRNAs assays. In this strategy, readout signals can be directly obtained from agarose gel without extra chemical labeling or amplification procedures. Considering the excellent performance of the logic gates with low levels of inputs, our plasmid DNA-derived nanowire strategy could provide a facile method to promote simultaneous multiple miRNA assays for the benefit of diagnosis and could be applied for the assembly of complex DNA nanostructures.