Color-Coded Traffic Signal Method Combined with Nanodiamond\nQuantum Sensing for Accurate miRNA Detection

Background\nnoise interferes with the accurate detection of early\ntumor biomarkers. This study introduces a method that effectively\nreduces background noise to enhance detection accuracy by combining\na color-coded signaling approach with the unique fluorescent properties\nand room-temperature tunable quantum spin characteristics of fluorescent\ndiamonds (FNDs) with nitrogen-vacancy centers. In this approach, a\nred signal indicates the presence of the target analyte within the\nspectral region, a green signal indicates its absence, and a yellow\nsignal indicates the need for further analysis using FNDs’\nquantum spin properties for optical detection magnetic resonance (ODMR)\nto distinguish the FND signal from background noise. Preliminary results\ndemonstrate that this method enables the detection of breast cancer-related\nmiRNA-21 and miRNA-96 concentrations as low as 1 fM within a 100 ×\n100 μm<sup>2</sup> area, achieving single-molecule detection\ncapability. This method is suitable for accurate biomarker identification\nand detection under high-background fluorescence conditions.