A research group led by Assoc. Prof. Hideyuki Mitomo and Prof. Kuniharu Ijiro at the Research Institute for Electronic Science (RIES), Hokkaido University, and Ms. Wenting Wei, a doctoral student at the Graduate School of Life Science, Hokkaido University, has developed a new technique that enables accurate and simple quantification of microRNA (miRNA) concentrations inside living cells.
MicroRNAs are small RNA molecules that play critical roles in regulating gene expression. Abnormal fluctuations in their intracellular levels are closely associated with the onset and progression of various diseases, including cancers and infections. Therefore, technologies that can accurately quantify miRNA concentrations inside living cells are crucial for developing diagnostic and therapeutic strategies.
In this study, the researchers designed a nanoscale DNA machine—called a bipedal DNA walker—assembled on gold nanoparticles and applied it as a sensor for intracellular miRNA detection. This DNA nanomachine possesses two “legs,” one producing a detection signal and the other producing an internal reference signal simultaneously. The system eliminates the need for complicated extraction or preprocessing and allows direct observation of living cells. This design enables self-correction of environmental variations such as local ion concentration, achieving highly precise quantification that was difficult with conventional single-signal-based methods. Using confocal fluorescence imaging, the team successfully visualized the spatial distribution of miRNA within living cells, revealing local differences in miRNA concentration that may relate to its biological functions.
This newly developed ratiometric detection strategy offers a powerful platform for accurate, quantitative, and simple analysis of trace nucleic acids in living cells, and is expected to contribute to advancements in cancer diagnosis, personalized medicine, and drug discovery research.
The research has been published in Analytical Chemistry (ACS) on October 21, 2025, and has been selected as a Supplementary Cover of the published issue.
Information of the paper
- Title
- Highly Sensitive and Quantitative Detection of microRNA-21 in Cells Using Bipedal DNA Walker-Based Ratiometric Fluorescent Sensor
- Authors
-
Wenting Wei, Han Lin, Kuniharu Ijiro* and Hideyuki Mitomo*
*Corresponding authors - Journal
- Analytical Chemistry (ACS)
- DOI
- 10.1002/acs.analchem.5c04705
- URL
- https://pubs.acs.org/doi/10.1021/acs.analchem.5c04705
Laboratory of Molecular Device
