Fluorescent DNA tetrahedral probe with catalytic hairpin self-assembly reaction for imaging of miR-21 and miR-155 in living cells

• DOI: 10.1007/s00604-024-06529-4
• Publication Date: 2024-07-11T13:01:56Z
• Authors: Shan Wang; Jiejie Guang; Yahui Gao; Bingyuan Fan; Yan Liang; Jinru Pan; Li Li; Wei Meng; Fang Hu
• Keywords: Tetrahedron; Fluorescence-lifetime imaging microscopy

A CHA-based fluorescent DNA tetrahedral probe (FDTp) has been designed to detect the microRNAs miR-21 and miR-155 sensitively and specifically in living cells. The design consisted of functional elements (H1, H2, and Protector) connected to a DNA tetrahedron modified with two pairs of fluorophores and quenching groups. In the presence of miR-21, the chain displacement effect was triggered and Cy3 fluorescence was emitted. In the presence of miR-155, the signal of the catalytic hairpin assembly (CHA) between H1 and H2 on FDTp was amplified, making the fluorescence of FAM sensitive to miR-155. Using this method, the detection limit for miR-155 was 5 pM. The FDTp successfully imaged miR-21 and miR-155 in living cells and distinguished a variety of cell lines based on their expression levels of miR-21 and miR-155. The detection and imaging of dual targets in this design ensured the accuracy of tumor diagnosis and provided a new method for early tumor diagnosis.