Boosting RNA-catalyzed DNA-Streptavidin Hydrogel Formation with Base-pair Mismatch for Enzyme-free Picomolar MicroRNA Detection
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초록
내용
MicroRNA (miRNA), which regulates the expression of various target genes, has been emerged as a key for disease diagnosis. Target-catalyzed toehold-mediated strand displacement (TMSD) is investigated for point-of-care testing of miRNA. However, TMSD-based RNA detection is challenging due to the relatively weak RNA-DNA binding. We introduced a single mismatch to the stem of hairpin DNA. The mismatch locally lowers the stability and enhances the reactivity of opening the hairpin by miRNA. Target miRNA catalyzed the cascade opening of three hairpin DNAs and forms multiple Y-shaped DNA (Y-DNA) tethered with biotin and quencher. The Y-DNA is self-assembled with Alexa594 labeled streptavidin, which produces hydrogel. In three-dimensional structure, Förster resonance energy transfer occurs between Alexa594 and quencher. The limit of detection is 60 pM. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (2020R1A2C2004168).