An electrochemical fluorescence dual-mode strategy for HER2-positive breast cancer cell detection

Breast cancer is one of the most prevalent malignancies worldwide, with HER2-overexpressing subtypes exhibiting increased aggressiveness and poorer prognosis. Accurate identification of HER2-positive subtypes is essential for the effective implementation of HER2-targeted therapy. In this study, an electrochemical fluorescence dual-mode strategy was developed for the high sensitive detection of HER2-positive breast cancer cells. Immunofluorescent quantum dot probes (IFQDs) with both fluorescence and enzyme catalysis were constructed. It labelled HER2 sites on the cell membrane to enable fluorescent imaging and cell counting. Furthermore, alkaline phosphatase (ALP) on the probe surface catalyzed the reduction of silver on the surface of the Au NPs@ITO electrode through enzyme-induced metallization, thereby enabling quantitative detection of the cells via stripping voltammetry. The application of two methods, namely enzyme-induced metallization and enrichment of signal species on the electrode surface, significantly enhanced the sensitivity of this analytical strategy. The self-monitoring of dual signals achieved more accurate analytical performance. The dual-mode strategy demonstrated satisfactory results in identifying breast cancer cells with varying HER2 expression levels and even in complex samples. It indicated that the electrochemical fluorescence dual-mode strategy had potential for typing and quantitative detection of cells with varying HER2 expression levels.