DNA Aptamer-Functionalized Fluorescent Silica Nanoparticles: A Robust Strategy for Specific Detection and Bioimaging of HER2-Overexpressing Breast Cancer

Background: Precise detection of HER2-positive breast cancer is vital for targeted therapy. This study integrates HER2-specific DNA aptamers with fluorescent silica nanoparticles (FSNPs) to develop a targeted imaging probe. Methods: HER2 aptamer-conjugated FSNPs (HApt-FSNPs) were synthesized and characterized. Specificity was evaluated in HER2-positive/negative cells and tumor sections via flow cytometry and microscopy. Targeting efficacy and biodistribution were assessed in tumor-bearing mice through systemic injection and real-time fluorescence imaging. Photostability and biosafety were systematically examined. Results: HApt-FSNPs showed uniform size, excellent dispersity, and enhanced photostability. They selectively bound HER2-positive cells and tumor tissues, with binding effectively blocked by free aptamer. In vivo imaging revealed specific accumulation in HER2-positive tumors, peaking at 6 hours post-injection, with minimal off-target signals. The probe demonstrated good biocompatibility in vitro and in vivo. Conclusion: The HApt-FSNP platform enables specific detection and in vivo imaging of HER2-positive breast cancer, highlighting its potential for diagnostic and bioimaging applications.