High Efficiency Molecular Delivery with Sequential Low-Energy Sonoporation Bursts

Area of Science:

• Biomedical Engineering
• Cell Biology
• Acoustic Medicine

Background:

• Sonoporation uses ultrasound and microbubbles to create temporary cell membrane pores for molecular delivery or extraction.
• Previous studies with polydisperse microbubbles reported a 50% sonoporation efficiency limit, considering cell death and lysis.

Purpose of the Study:

• To exceed the 50% sonoporation efficiency limit using monodisperse microbubbles.
• To investigate the impact of microbubble size and sequential sonoporations on molecular delivery efficiency and cell viability.

Main Methods:

• Utilized a physiotherapy ultrasound device (1.0 MHz, 2.0 W/cm², 10% duty cycle) with monodisperse microbubbles.
• Examined the effects of different microbubble sizes (2, 4, and 6 µm) on cellular uptake (FITC-dextran) and cell death in HeLa cells.
• Employed sequential sonoporations (up to four) to enhance molecular delivery and confirmed results with TRITC-dextran.

Main Results:

• Smaller microbubbles (2 µm) showed a better uptake-to-death ratio (4:1) compared to larger ones (1:2 for 6 µm).
• Sequential sonoporations significantly increased molecular delivery, achieving a peak uptake of 66.1% after two treatments.
• The study successfully overcame the 50% efficiency limit, with controlled cell lysis (7.0%) and death (17.9%).

Conclusions:

• Monodisperse microbubbles, particularly smaller ones, enable efficient in vitro sonoporation.
• Multiple low-energy sonoporation bursts can overcome previous efficiency limitations for enhanced molecular delivery.
• This approach offers a promising strategy for advanced theranostic applications requiring high cellular uptake.