A brief note on experimental setups for in-vitro optical observations of HeLa cells and phospholipid-shelled microbubbles subjected to ultrasound

In a recent issue of Physics in Medicine, Akashi et al. demonstrated increased mortality of HeLa cells in combination with phospholipid-shelled microbubbles under high-amplitude sonication in an in-vitro experimental setup [1]. The authors attributed the increased mortality to cell damage caused by microbubble dynamics and mentioned the term sonoporation early in their paper. Their findings are a most valuable contribution with regards to ultrasonic imaging safety standards. However, the findings would be even more beneficial to the drug delivery community, provided they could be linked to previous outcomes on in-vitro experimental sonoporation. The purpose of this paper is to briefly underscore previous works with similar setups, highlighting the many agreements between early and recent work.