Affibody-based nanoprobes for HER2-expressing cell and tumor imaging

This article reports the affibody-based nanoprobes specifically target and image human epidermal growth factor receptor type 2 (HER2)-expressing cells and tumors. The affibody molecules are a promising class of targeting ligands with simple, robust, and precise structure and high affinity. Using near-infrared (NIR) quantum dots (QDs) and iron oxide (IO) nanoparticles as two representative nanomaterials, we designed anti-HER2 affibody molecules with a N-terminus cysteine residue (Cysteine-Z(HER2:342)) and precisely conjugated with maleimide-functionalized nanoparticles to make nanoparticle-affibody conjugates. The in vitro and in vivo study showed the conjugates are highly specific to target and image HER2-expressing cells and tumors. This work indicated the nanoparticle-affibody conjugates may be excellent candidates as targeting probes for molecular imaging and diagnosis.