Ultrasensitive Fluorescence Detection of Lung Cancer-Related miRNAs Based on DNA Tetrahedron and DNAzyme Catalytic Reaction

Early detection and treatment of lung cancer are critical for enhancing therapeutic efficacy and reducing mortality rates. Recognizing the significance of early lung cancer diagnosis, this study presents an ultrasensitive fluorescence method for detecting the lung cancer biomarker miRNA-205 in cell lysate and serum, utilizing a combination of DNA tetrahedral nanostructures and the DNAzyme catalytic reaction. The research initially designed a DNA tetrahedral nanostructure incorporating a DNAzyme sequence, paired with a complementary sequence (cDNA) capable of hybridizing with miRNA-205, thus inhibiting DNAzyme activity. In the presence of miRNA-205, the hybridization between miRNA-205 and cDNA activates the DNAzyme, which subsequently cleaves RNA bases in the fluorescent substrate modified on magnetic microsphere surfaces. The cleaved fluorescent substrate becomes unstable, dissociates, and releases into the supernatant, generating a fluorescent signal. The DNAzyme then binds to the next fluorescent substrate for a new cyclic cleavage round, significantly amplifying the fluorescent signal. Under optimized conditions, this fluorescence method demonstrates the capability to detect miRNA-205 at concentrations as low as 5.8 pM. Notably, the method exhibits exceptional selectivity and interference resistance, enabling the detection of miRNA-205 in complex matrices such as serum samples and cell lysates. This work provides a robust and selective analytical platform, paving the way for its future evaluation in clinical research.