Effect of Acoustic Radiation Force on the Distribution of Nanoparticles in Solid Tumors

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control Vol. 68; no. 3; pp. 432 - 445
• Main Authors: Afadzi, Mercy, Myhre, Ola Finneng, Yemane, Petros T., Bjorkoy, Astrid, Torp, Sverre H., van Wamel, Annemieke, Lelu, Sylvie, Angelsen, Bjorn A. J., de Lange Davies, Catharina
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.03.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acoustic beams; Acoustic radiation force (ARF); Acoustics; Blood vessels; Electronic countermeasures; extravasation; focused ultrasound (FUS); Force; Force distribution; interstitial displacement; Mathematical model; nanoparticle (NP) delivery; Nanoparticles; Sound waves; Stress concentration; Transducers; Tumors
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2020.3027072

Acoustic radiation force (ARF) might improve the distribution of nanoparticles (NPs) in tumors. To study this, tumors growing subcutaneously in mice were exposed to focused ultrasound (FUS) either 15 min or 4 h after the injection of NPs, to investigate the effect of ARF on the transport of NPs across the vessel wall and through the extracellular matrix. Quantitative analysis of confocal microscopy images from frozen tumor sections was performed to estimate the displacement of NPs from blood vessels. Using the same experimental exposure parameters, ARF was simulated and compared with the experimental data. Enhanced interstitial transport of NPs in tumor tissues was observed when FUS (10 MHz, acoustic power 234 W/cm 2 , 3.3% duty cycle) was given either 15 min or 4 h after NP administration. According to acoustic simulations, the FUS generated an ARF per unit volume of <inline-formula> <tex-math notation="LaTeX">2.0\times 10^{{6}} </tex-math></inline-formula> N/m 3 . The displacement of NPs was larger when FUS was applied 4 h after NP injection compared with after 15 min. This study shows that ARF might contribute to a modest improved distribution of NPs into the tumor interstitium.