Combined near-IR photothermal therapy and chemotherapy using gold-nanorod/chitosan hybrid nanospheres to enhance the antitumor effect

Abstract

Motivated by the enhanced cytotoxicity of some chemotherapeutic agents at temperature rise, multifunctional chitosan nanospheres which co-carried gold nanorods and cisplatin were prepared. These hybrid nanospheres were characterized by dynamic light scattering, zeta potential, UV-Vis absorption spectra and transmission electron microscopy. It was demonstrated that these 120 nm-sized hybrid nanospheres could be selectively accumulated at the tumor site with about 11% injection dose per g of tumor, and produced local hyperthermia to an average temperature of 49 °C in tumor tissue after near-IR irradiation for 10 min. Due to the enhanced cytotoxicity of cisplatin at elevated temperatures, cisplatin-loaded hybrid nanospheres showed about one-second lower IC₅₀ values than hybrid nanospheres alone in vitro and almost complete tumor growth inhibition in vivo. Compared with chemotherapy or photothermal treatment alone, the combined photothermal therapy and chemotherapy had a significantly synergistic effect and improved the therapeutic efficacy, which was supported by immunofluorescence staining and in vivo apoptosis imaging.