Assessing Fab-Functionalized Gold Nanoparticles-Mediated Thermal Enhancement during High-Intensity Focused Ultrasound Ablation in a Mouse Tumor Model.

High-intensity focused ultrasound (HIFU) stands out as a noninvasive modality that is gaining prominence for the localized treatment of malignant tumors. A mouse tumor model was used to assess the level of thermal enhancement afforded by Fab-functionalized gold nanoparticles (gNPs) during HIFU treatment. Prostate cancer cells (PC3) were used to grow tumors on the right flank of immunodeficient NSG mice. Three levels of gNPs concentrations (0%, 0.019%, and 0.125%) were injected directly into the tumors. HIFU sonication was performed at acoustic power levels of 30W, 40W, and 50W for the duration of 16 s inside a 1.5 T magnetic resonance system. Temperature rise data were recorded for each power level and gNPs concentration during the experiment and analyzed. Tumors were harvested 4 h after the sonication for a histopathology study. A histopathology study was conducted using hematoxylin and eosin (H&E) as well as cleaved caspase 3 (CC3) staining. For an acoustic power of 50W, temperature increases of 16.77 ± 2.33 °C, 19.95 ± 2.98 °C, and 27.78 ± 5.31 °C were recorded for gNPs concentrations of 0%, 0.019%, and 0.125%, respectively. Also, for an acoustic power of 50W, thermal doses of 0.08, 282.87, and 31563.70 min were obtained for gNPs concentrations of 0%, 0.019%, and 0.125%, respectively. Cellular damage around the focus was observed in histopathology studies using H&E staining in HIFU-treated tumors.