On the molecular release induced by ultrasound and microbubbles in cells
Ultrasound and microbubble (USMB) enhances intracellular uptake through membrane disruption and endocytosis. This study investigates USMB effects on the molecular release incells through membrane-disruption and exocytosis. Retinal pigmented epithelial (RPE) cells were loaded with Alexa 647-transferrin (Tfn) to mark recycling endosomes, LAMP-1 antibody was used to mark lysosomes, GFP-transfected RPE cells were used to mark cytoplasm, and 7-AAD was used to assess cell viability. USMB exposure was done at 570kPa peak negative pressure for 1min. The mean fluorescent intensities (MFI) of markers were measured using flow cytometry. USMB induced the release of 19% and 67% of GFP from the cytoplasm in viable and non-viable cells respectively. LAMP-1 antibody MFI increased by 50% and 15-folds in viable and non-viable cells indicating USMB induced release from lysosomes. Furthermore, Tfn release from recycling endosomes increased by 22% only in viable cells. In conclusion, USMB enhances the molecular release from cytoplasm, lysosomes, and recycling endosomes