Robust ERα-Targeted Near-Infrared Fluorescence Probe for Selective Hydrazine Imaging in Breast Cancer

Breast cancer is the most common malignancy in women and may become worse when a high concentration of hydrazine is absorbed from the environment or drug metabolite. Therefore, rapid and sensitive detection of hydrazine in vivo is beneficial for people's health. In this work, a novel estrogen receptor α (ERα)-targeted near-infrared fluorescence probe was designed to detect hydrazine levels. The probe showed good ERα affinity and an excellent fluorescence response toward hydrazine. Selectivity experiments demonstrated that the probe had a strong anti-interference ability. Mechanistic studies, including mass spectrometry (MS) and density functional theory (DFT) calculation, indicated that intermolecular charge transfer (ICT) progress was hindered when the probe reacted with hydrazine, resulting in fluorescent quenching. In addition, the probe could selectively bind to MCF-7 breast cancer cells with excellent biocompatibility. The in vivo and ex vivo imaging studies demonstrated that the probe could rapidly visualize hydrazine with high contrast in MCF-7 xenograft tumors. Therefore, this probe can serve as a potential tool to robustly monitor hydrazine levels in vivo.