Detection of Mirna-21 in the Early Stages of Lung and Ovarian Cancers Using a Fluorescent Biosensor Designed Through Ssdna Binding With a [Ru(Bpy)2(Fmp)](Clo4)2 Complex Publisher

Summary: Can light detect a cancer-linked microRNA? A novel fluorescent sensor detected miR-21 down to 0.10 pM in plasma and cancer-cell samples. #Biosensors #CancerResearch

Zoughi S ; Faridbod F ; Amiri A
Source: Materials Advances Published:2026

Abstract

This work presents a novel optical biosensor for the sensitive detection of miR-21-5p, employing a polypyridyl ruthenium(II) complex as a fluorescent probe. The discovery of the special binding of an ssDNA sequence to a fluorescent polypyridyl ruthenium (ii) complex led us to design a selective and sensitive fluorescent biosensor. In the new structure, repulsive forces from the negative charge on ssDNA moieties act as spacers, reducing intermolecular interactions and minimizing quenching effects, enhancing the fluorescence emission of the complex. Moreover, the ssDNA sequence is a complementary sequence of miR-21, enabling specific detection of the target. Upon interaction with miR-21, the ssDNAs hybridize with the target sequence and quench the fluorescence of the designed probe. The response of the biosensor can be considered as the decrease in fluorescence emission of the probe, which is proportional to the increase in concentration of miR-21. The biosensor exhibited a linear response over the range of 0.50–50.0 pM, with a limit of detection of 0.10 pM. The proposed method was successfully applied to miR-21 detection in plasma and human ovarian and lung cancer cell samples. This journal is © The Royal Society of Chemistry, 2026.