Abstract
Histotripsy employs acoustic inertial cavitation to mechanically destroy tissue, producing acellular debris. While introducing bubbles can lower the cavitation threshold and enhance treatment efficiency, micrometer-scale bubbles struggle to penetrate tissues effectively. Shell-less nanobubbles, with their high internal pressure, stability, negatively charged surfaces, and unique lifetimes ranging from weeks to months, offer a promising alternative. However, their interactions with ultrasound remain unexplored. This study used a claw-type pump nanobubble generator to produce nanobubbles and employed acoustic and optical methods to observe their behavior under high-intensity ultrasound exposure. The results demonstrated that the device generated nanobubble solutions with an average particle size of 107 nm, a concentration of 1.94 × 10(9) particles/mL, a lifetime exceeding one week, and a zeta potential of -21.2 mV. Acoustic and optical observations further revealed that nanobubble solutions reduced the inertial cavitation threshold of the liquid from 26.5 MPa to 10.3 MPa. These findings suggest a potential strategy to enhance the efficiency of ultrasound histotripsy treatments.