Anti-HER2/neu peptide-conjugated iron oxide nanoparticles for targeted delivery of paclitaxel to breast cancer cells

Nanoparticles (NPs) for targeted therapy are required to have appropriate size, stability, drug loading and release profiles, and efficient targeting ligands. However, many of the existing NPs such as albumin, liposomes, polymers, gold NPs, etc. encounter size limit, toxicity and stability issues when loaded with drugs, fluorophores, and targeting ligands. Furthermore, antibodies are bulky and this can greatly affect the physicochemical properties of the NPs, whereas many small molecule-based targeting ligands lack specificity. Here, we report the utilization of biocompatible, biodegradable, small (∼30 nm) and stable iron oxide NPs (IONPs) for targeted delivery of paclitaxel (PTX) to HER2/neu positive breast cancer cells using an anti-HER2/neu peptide (AHNP) targeting ligand. We demonstrate the uniform size and high stability of these NPs in biological medium, their effective tumour targeting in live mice, as well as their efficient cellular targeting and selective killing in human HER2/neu-positive breast cancer cells.