Abstract
A simple fluorescent biosensor was developed for the simultaneous determination of the breast cancer-related biomarkers human epidermal growth factor receptor 2 (HER2) and microRNA-21. Black Hole Quencher 2 (BHQ2) labeled DNA1, carboxyl fluorescein (FAM)-modified human epidermal growth factor receptor 2 (HER2) aptamers, and sulfo-cyanine5 carboxylic acid (Cy5)-modified DNA2 were involved. The fluorescent probe was prepared by a one-step procedure. In this sensing system, FAM and Cy5 were close to BHQ2, and therefore, the fluorescent intensity of this proposed probe was weak. However, in the presence of HER2 and microRNA-21, the fluorescent signals were enhanced with increasing concentrations. The detection of HER2 and microRNA-21 was achieved in a simple process. The detection limits for HER2 and microRNA-21 were 0.042 ng mL−1 and 0.048 pM, respectively. In summary, this analytical approach is simple, rapid, cost-effective, low cost, selective, and accurate which are important characteristics in clinical analysis. Therefore, we anticipate that this fluorescent biosensing protocol may have practical applications in clinical measurements to provide early disease diagnosis and monitoring.