Abstract
The role of liposomes as drug carriers has been investigated. Ultrasound-based drug release methods have been developed for on-demand drug delivery. However, the acoustic responses of current liposome carriers result in low drug release efficiency. In this study, CO2-loaded liposomes were synthesized under high pressure from supercritical CO2 and irradiated with ultrasound at 237 kHz to demonstrate their superior acoustic responsiveness. When liposomes containing fluorescent drug models were irradiated with ultrasound under acoustic pressure conditions that are safe for the human body, CO2-loaded liposomes synthesized using supercritical CO2 had 17.1 times higher release efficiency than liposomes synthesized using the conventional Bangham method. In particular, the release efficiency of CO2-loaded liposomes synthesized using supercritical CO2 and monoethanolamine was 19.8 times higher than liposomes synthesized using the conventional Bangham method. These findings on the release efficiency of acoustic-responsive liposomes suggest an alternative liposome synthesis strategy for on-demand release of drugs by ultrasound irradiation in future therapies.