Design and Fabrication of a DNA-copper Nanocluster-based Biosensor for Multiple Detections of Circulating miRNAs in Early Screening of Breast Cancer.

Breast cancer is one of the most prevalent cancers and a significant cause of fatalities in women. Diagnosis of breast cancer faces substantial challenges, owing to the multi-factored nature of the illness. Thus, the necessity for an inexpensive, rapid, and non-invasive diagnostic method that enables early detection with high sensitivity and specificity is of primary significance. In this study, a biosensor based on the fluorescence emission of DNA-templated Cu nanoclusters was designed to simultaneously detect and quantify three significant biomarkers of breast cancer (circulating microRNAs, miR-21, miR-195, and miR-155). Fluorescence spectroscopy, FESEM and TEM microscopy, and DLS confirmed the validation of the biosensor. A detection limit of 1.7 pM with a linearity range of 500 nM to 3 µM was obtained. In conclusion, the innovative selection of three biomarkers, the utilization of the HCR process, and an the elaborated design of probes are considered to be among the most important advantages of this biosensor, enabling it a simultaneous triple diagnosis of the blood specific circulating microRNAs without a need for any enzymes, thermo-cycles, expensive or complex facilities, linkers, fluorescent tags, and time-consuming methods.