Micro-localized cell lysis by low power Focused Acoustic Transducer

In this study, we designed and fabricated Self Focused Acoustic Transducer (SFAT) for micron-sized localized cytolysis. Monolayer 22RV1 prostate cancer cells were cultured in the cell culture chamber and locally lysed by the SFAT. Various electric powers and operating frequencies of actuating pulsed signal were applied to characterize the localized cell lysis effects. The cell lysis area was around 2.28×10^-9 m² and 1.64×10^-9 m², when the acoustic waves produced by the transducer were 17.3 and 52 MHz, respectively. The minimum electric power required for the cell lysis of 22RV1 is as low as 9 mW, which produces an acoustic intensity 0.15 W/cm² at the focal spot. The amount of mRNA released in the culture media was increased more than 10 times after the cytolysis. According to experiment results, the size of lysed cells area is determined by the acoustic-wave frequency, and very little by the electric power applied to the device above a threshold. Signs of inertia cavitation phenomena such as bubble generation or temperature raise were not observed. Therefore, low-power micron-sized cell lysis without cavitation may have practical applications relating to cancer diagnosis and therapeutics.