Site-Specific Fluorescent Labeling of Antibodies and Diabodies Using SpyTag/SpyCatcher System for In Vivo Optical Imaging.

These results highlight the ease and utility of using the modular SpyTag/SpyCatcher protein ligase system for site-specific fluorescent labeling of protein-based imaging probes. Imaging probes labeled in this manner will be useful for optical imaging applications such as image-guided surgery and have broad application for other imaging modalities.