Early Diagnosis\nof Triple-Negative Breast Cancer Based\non Dual microRNA Detection Using a Well-Defined DNA Crown-Carbon Dots\nStructure as an Electrochemiluminescence Sensing Platform

Triple-negative breast cancer (TNBC) is the most aggressive\nsubtype\nof breast cancer (BC). Thus, early detection and accurate diagnosis\nof this cancer are crucial for improving the survival rate of patients.\nSpecific microRNAs (miRNAs) have been implicated in the occurrence,\nproliferation, and metastasis of TNBC. Addressing this need, our study\ndeveloped a biosensor platform for early and accurate TNBC diagnosis\nby integrating electrochemiluminescence (ECL) technology with a DNA\nsensing strategy. Specifically, synthesized positively charged carbon\ndots (CDs) were used to neutralize the electrostatic repulsion between\nDNA strands and facilitate the assembly of DNA triangular prisms (DNA\nTP-CDs). Hairpins were then incorporated into the DNA TP-CDs to form\nthe final DNA crown structure. The early TNBC biomarker, microRNA-93–3p\n(miR-93–3p), allowed for the binding between the DNA Crown\nand the DNA track on the electrode and initiated the ECL signal. Subsequently,\nmicroRNA-210 (miR-210) unlocked the DNA tripedal walker, and its movement\non the DNA Crown eventually quenched the ECL signal, enabling accurate\nTNBC diagnosis and tumor stage assessment. Our proposed biosensor\nhad satisfactory sensing efficiency due to the ordered DNA track and\nrapid-moving DNA walker. The data revealed a good linear relationship\nbetween the ECL signals and the logarithm of miRNA concentrations,\nwith miR-93–3p having a detection limit of 31.04 aM and miR-210\nhaving a detection limit of 7.69 aM. The biosensor also showed satisfactory\nperformance in serum samples and cells. Taken together, this study\nhopes to provide ideas and applications for clinical diagnosis as\nwell as the personalized treatment of TNBC.