High-frequency subharmonic imaging of liposome-loaded microbubbles

The therapeutic application of microbubbles is a highly active area of research, since they can be used for drug or gene delivery. The mouse model is a necessary step in the validation of any new therapeutic agent and high-frequency ultrasound imaging is a common tool used to study this. Attachment of drug-filled liposomes to the shell of a phospholipid microbubble is a common approach for the delivery of a therapeutic payload with ultrasound contrast agents. This study demonstrated that the attachment these drug-filled liposomes had a negligible effect on their response under high frequency ultrasound imaging at 40 MHz and resulted in subharmonic emissions at lower transmit power and greater magnitude in vitro and in vivo.