Targetable gold nanorods for epithelial cancer therapy guided by near-IR absorption imaging

Well-designed nanoparticle-mediated, image-guided cancer therapy has attracted interest for increasing the efficacy of cancer treatment. A new class of smart theragnostic nanoprobes employing cetuximab (CET)-conjugated polyethylene glycol (PEG)ylated gold nanorods (CET-PGNRs) is presented; these nanoprobes target epithelial cancer cells using near-infrared light. The cetyltrimethylammonium bromide bilayer on GNRs is replaced with heterobifunctional PEG (COOH-PEG-SH) to serve as a biocompatible stabilizer and to increase specificity. The carboxylated GNRs are further functionalized with CET using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC-NHS) chemistry. To assess the potential of such GNRs, their optical properties, biocompatibility, colloidal stability, in vitro/in vivo binding affinities for cancer cells, absorption imaging, and photothermal therapy effects are investigated. CET-PGNRs exhibit excellent tumor targeting ability and strong potential for simultaneous absorption imaging and photothermal ablation of epithelial cancer cells.