Targeted Microbubbles for Drug, Gene, and Cell Delivery in Therapy and Immunotherapy

Microbubbles are 1-10 & mu;m diameter gas-filled acoustically-active particles, typically stabilized by a phospholipid monolayer shell. Microbubbles can be engineered through bioconjugation of a ligand, drug and/or cell. Since their inception a few decades ago, several targeted microbubble (tMB) formulations have been developed as ultrasound imaging probes and ultrasound-responsive carriers to promote the local delivery and uptake of a wide variety of drugs, genes, and cells in different therapeutic applications. The aim of this review is to summarize the state-of-the-art of current tMB formulations and their ultrasound-targeted delivery applications. We provide an overview of different carriers used to increase drug loading capacity and different targeting strategies that can be used to enhance local delivery, potentiate therapeutic efficacy, and minimize side effects. Additionally, future directions are proposed to improve the tMB performance in diagnostic and therapeutic applications.

Automated summary

Microbubbles, with a diameter of 1-10 & mu;m, are gas-filled particles stabilized by a phospholipid monolayer shell. They can be used as targeted ultrasound imaging probes and carriers for drug and cell delivery. This review summarizes current targeted microbubble (tMB) formulations and their applications in ultrasound-targeted delivery. The review also discusses different strategies to enhance local delivery, improve therapeutic efficacy, and minimize side effects, as well as future directions for improving tMB performance in diagnostic and therapeutic applications.