Assessment of Enhanced Thermal Effect Due to Gold Nanoparticles during MR-Guided High-Intensity Focused Ultrasound (HIFU) Procedures Using a Mouse-Tumor Model

Abstract

An in vivo study was conducted using a mouse tumor model, to assess the utility of using gold nanoparticles (gNPs) during HIFU procedures to locally enhance heating at low powers. Tumors were grown using melanoma tumor cells (B16/F10) subcutaneously on the right flanks of mice (C57Bl/6J). Physiologically relevant concentrations (0 and 0.125%) of gNPs were directly injected into the tumors. Sonications at acoustic powers of 10 and 30 W were performed for a duration of 16 s inside a magnetic-resonance system. Temperature increases and lesion volumes were calculated and compared for procedures with and without gNPs. Histopathology study was conducted using a cleaved caspase 3 antibody and hematoxylin and eosin staining after removing the tumors from the mice. For an acoustic power of 30 W, end-of-sonication temperature increases of 25.4 ± 3.8 °C (0% gNP) and 42.2 ± 4.6 °C (0.125% gNP) were measured. Using cleaved caspase 3 antibody, it was observed that more than 1% of nuclei are affected in the case of 0.125% and 30 W but only 0.01% of nuclei are affected in the 0% case. For 30 W and a gNP concentration of 0.125%, a lesion volume of 0.33 ± 0.22 mm 3 was obtained, while no lesion was observed without gNP's.

Nanomedicines for high‑intensity focused ultrasound cancer treatment and theranostics (Review)

“…By using MRI thermometry to evaluate the tissue temperature, Devarakonda et al ( 108 ) discovered that the addition of gold NPs significantly enhances the increase in temperature to increase lesion volume compared with HIFU ablation alone. This enhancing effect of gold NPs was also confirmed in vivo ( 109 ), although a localized direct injection of NPs into the superficial tumour tissue was used, which is not a method used in clinical practice. Thus, further intravenous injection studies are required to assess the theranostic efficacy of gold NPs and their impact on efficacy of HIFU ablation.…”