Laser-induced focused ultrasound for noninvasive sonothrombolysis using candle soot polymer nanocomposite-coated photoacoustic lens

In this paper, a concave carbon-based polymer nanocomposite film was developed for high-amplitude focused ultrasound. The composite films consisting of candle soot nanoparticles (CSNPs) and elastomeric polymers were used as the high-frequency optoacoustic sources. To generated focused ultrasound, these composite films were formed on concave optical lens. A focal waveform with peak to peak pressure of similar to 45 MPa was achieved at the focal point. The prototyped laser-induced focused ultrasound (LIFU) was applied with noninvasive sonothrombolysis in vitro. For enhanced cavitation effect, we demonstrated a spatio-temporal superposition approach of LIFU treatment in conjunction with low-frequency focused ultrasound from a piezoelectric ultrasound transducer. The in vitro results showed that dual-frequency excitation ultrasound treatment can achieve the sonothrombolysis efficiency of approximately 28% in half of an hour (2 mg/min), suggesting that LIFU generated from composite films may be promising in precision sonothrombolysis.