Nano‐Mediated Fluorescence Switching for Epidermal Growth Factor Receptor Detection

Identification of the epidermal growth factor receptor (EGFR) in biological specimens is essential for cancer diagnostics, drug development and therapeutic monitoring. However, real-time techniques for accurate EGFR expression monitoring are currently limited. In this study, we report the development of a novel nano detector (Cy3-Apt_EGFR@BPNSs) with the capabilities of quenching and recovery to enable visual EGFR expression analysis. Cy3-Apt_EGFR is a Cy3-labelled single-stranded RNA (ssRNA) that exhibits specific binding to EGFR. Black phosphorus nanosheets (BPNSs) possess the ability to adsorb Cy3-Apt_EGFR via van der Waals forces, quenching its fluorescence when combined. The detection of EGFR receptors on cancer cell surfaces prompts the release of Cy3-Apt_EGFR from BPNSs, a consequence of the robust binding interaction between the receptor and aptamer, thereby leading to fluorescence reinstatement. The recovered fluorescence intensity of this detector is found to be directly correlated with EGFR expression levels in cancer cells, indicating its potential for guiding tumour diagnosis and treatment. The specificity of Cy3-Apt_EGFR@BPNSs further enhances its utility in detecting EGFR. More importantly, our research demonstrates that the reduction in EGFR expression levels within cancer cells corresponds to a proportional decline in fluorescence intensity, thereby facilitating precise tracking of EGFR dynamics.