Tumor Regression <i>In Vivo</i> by Photothermal Therapy Based on Gold-Nanorod-Loaded, Functional Nanocarriers

TLDR

The nanocarriers previously demonstrated long circulation, good tumor accumulation, and low liver uptake in vivo. The study aimed to develop an effective hyperthermia system for photothermal cancer therapy. The system uses gold nanorods loaded into chitosan‑conjugated, Pluronic‑based nanocarriers that are cross‑linked to provide stable storage and tumor‑targeted delivery. In vitro, the nanocarrier‑loaded GNRs showed enhanced cellular uptake and photothermal effect; in vivo, intravenous injection followed by NIR irradiation caused efficient tumor thermolysis and complete tumor resorption without harming surrounding tissue.

Abstract

We developed a very effective hyperthermia system for successful photothermal cancer therapy. Instead of applying individual gold nanorods (GNRs) that can absorb NIR light, GNRs were loaded into functional nanocarriers that could provide stable storage of GNRs and selective delivery to a target tumor site. The functional nanocarriers (chitosan-conjugated, Pluronic-based nanocarriers) were prepared by chemically cross-linking Pluronic F 68 with chitosan conjugation to form a flexible, soft, and excellent reservoir for biomacromolecules as well as tumor targeting. In vivo characteristics of the nanocarriers including a long circulation time, a good tumor accumulation, and low liver uptake were previously characterized by us. When GNRs were delivered by using these nanocarriers, much enhanced in vitro cellular uptake and a photothermal effect were observed for a cancer cell line. More importantly, an intravenous injection of this system followed by NIR laser irradiation to the tumor site resulted in a very efficient thermolysis in vivo. Thus, apparently complete tumor resorption was achieved without damage to the surrounding tissue, suggesting a promising candidate for clinical phototherapeutic applications.