Photocrosslinkable Artificial Nucleic Acid Probe Based miRNA Biosensor

Molecular recognition elements like enzymes, antibodies, and nucleic acids, which are involved in specific binding, are important components in biosensing technologies. These biomolecular recognition elements are based on molecular interactions such as hydrogen bonding, van der Waals forces, and hydrophobic interactions. However, these interactions are often affected by the solution environment such as pH, temperature, and salt concentration, which are the rate-limiting factors for biosensing applications. In this study, we focused on molecular recognition using photocrosslinkable artificial nucleic acids. Photocrosslinkable artificial nucleic acids can form covalent bonds with target nucleic acids upon photoirradiation after hybridization. The covalent bonds formed are stronger than those in conventional molecular recognition and are not affected by the solution environment. Herein, we propose a biosensing system that combines molecular recognition by photocrosslinkable artificial nucleic acids, isothermal amplification by hybridization chain reaction, and electrochemical detection of miR-21 as the target molecule, which has recently attracted attention as a cancer biomarker. This technology eliminates non-specific binding and enables biosensing measurements with a suppressed background.