Ultrasound triggered drug delivery with liposomal nested microbubbles

Area of Science:

• Biomaterials Science
• Acoustic Engineering
• Drug Delivery Systems

Background:

• Liposomes are widely used for drug delivery due to their biocompatibility.
• Controlled release of encapsulated drugs from liposomes remains a challenge.
• Ultrasound contrast agents offer potential for triggered therapeutic applications.

Purpose of the Study:

• To investigate the triggered release of liposomal contents using ultrasound contrast agent microbubbles.
• To characterize the mechanisms of liposome membrane disruption by microbubble cavitation.
• To determine the influence of ultrasound parameters on drug release kinetics.

Main Methods:

• Encapsulation of ultrasound contrast agent microbubbles within liposomes.
• Exposure of liposomes to focused ultrasound (1 MHz) at varying pressures.
• Quantification of aqueous core release using fluorescence assays.
• Qualitative assessment of membrane integrity via optical microscopy.

Main Results:

• Triggered release of liposomal contents was dependent on the presence of microbubbles.
• Two distinct release regimes were observed based on ultrasound pressure.
• High pressures (2.1-3.7 MPa) induced rapid release and permanent membrane damage.
• Low pressures (0.54-1.7 MPa) resulted in slower release, dilation, and temporary poration.

Conclusions:

• Microbubble-mediated ultrasound cavitation provides a viable method for triggered liposomal drug release.
• Ultrasound pressure is a critical parameter controlling the rate and extent of liposome membrane disruption.
• This approach holds promise for targeted and controlled drug delivery applications.