Antibody-functionalized gold nanospheres for multimodal imaging

The first near-infrared (NIR-I) spectral window (700–900 nm) enables deeper tissue penetration and reduced autofluorescence, improving sensitivity for in vivo imaging. However, the relatively low fluorescence intensity of many NIR fluorophores limits their effectiveness. Here, we report the development of gold nanodye (AuND) by conjugating gold nanospheres (AuNSs) with IRDye 800 NHS ester via polyethylene glycol (PEG) linkers and functionalizing them with epidermal growth factor receptor (EGFR) targeting antibodies (Anti-AuND). This design enhances fluorescence emission through plasmonic interactions while simultaneously exploiting the high X-ray attenuation of gold for computed tomography (CT) contrast. Using Anti-AuND, we established a multimodal imaging platform integrating CT, NIR fluorescence, and fluorescence lifetime (FLT) imaging in a preclinical mouse model of EGFR-overexpressing head and neck cancer. Anti-AuND enabled high-sensitivity, high-resolution tumor visualization in vivo. The combined imaging approach provides complementary anatomical and molecular information, highlighting the potential of Anti-AuND for early cancer detection and translational biomedical imaging applications.