Folate-targeted gold nanorods for effective combined photothermal-chemotherapy of osteosarcoma

Abstract

Osteosarcoma (OS) is the most common primary malignant neoplasm of bone. The annual incidence of osteosarcoma is 8-11 per million in the age group of 15-19 years. Despite its rarity, it has been reported to be the second leading cause of cancer-related deaths in children and young adults. In particular with regard to OS therapy, a variety of nanostructures have been exploited in the areas of OS imaging. Among them, Gold nanorods (AuNRs) have unique optical and chemical-physical properties that make them appealing for biomedical applications such as photothermal therapy, drug delivery and imaging of solid tumors. The noble metal core is biologically inert, contributing to low toxicity and good biocompatibility. Their large surface area and their high affinity for thiol groups allows their easy surface functionalization, so that therapeutic agents, targeting ligands and biocompatible coatings can be introduced. AuNRs also display the phenomenon of Surface Plasmon Resonance (SPR), resulting in large absorption band in the visible and near-Infra Red (NIR), whose wavelength depends on the AuNRs dimensions and shape. When laser-irradiated, AuNRs convert the absorbed radiation into heat and can act as two photon luminescence contrast agent. However AuNRs cannot be administered in vivo without a proper coating, due to their low stability in aqueous media.