Phospholipids-based microbubbles sonoporation pore size and reseal of cell membrane cultured in vitro

Objective: To investigate phospholipids-based microbubbles induced sonoporation and cell membrane reseal in vitro under various conditions. Methods: A breast cancer cell line SK-BR-3 was used to investigate ultrasonic sonoporation under various conditions. Atomic force microscopy (AFM) scanning techniques were employed to observe the change of membrane pores. Results: Normal SK-BR-3 cells membrane pores were evenly distributed and less than 1m. After ultrasound exposure, membrane pores were enlarged at different degree depending on ultrasound exposure durations, filling gas species and microbubble suspension concentration. With microbubble suspension concentration being increased to 5% or ultrasound exposure reached 30s, membrane pores in fluorocarbon (C3F8 or SF6)-filled microbubble groups exceeded 1m, which were significantly larger than that of air-filled microbubble group. Membrane pores were about 2-3m under ultrasound 60s with 5% fluorocarbon-filled microbubble suspension. After 24h of incubation, most of the enlarged membrane pores could reseal to normal size, which corresponded to cell viability. Conclusions: Membrane pores can be obviously enlarged by ultrasonic sonoporation of fluorocarbon-filled microbubbles, whose reseal time depended on ultrasound exposure duration and microbubble suspension concentration.