ABSTRACT
Gas microbubbles stabilised by a surfactant or polymer coating have now been in clinical use as contrast agents for ultrasound imaging for several decades. More recently, their use in therapeutic applications, in particular drug delivery and gene therapy, has also become a highly active area of research. There remain, however, some signišcant challenges that must be overcome in order to fully realise the potential of microbubbles in these applications. In particular, the difšculty in controlling the concentration of microbubbles at a given site and in ensuring sufšcient proximity between bubbles and target cells has frequently led to disappointing results from in vivo studies. Recent work has indicated that incorporating magnetic nanoparticles into the microbubble coating may provide an effective strategy for overcoming these challenges, by both enabling the bubbles to be localised using an externally applied magnetic šeld and enhancing the efšciency of cell uptake. This chapter will brie™y describe the uses of microbubble agents in medical imaging and therapy and then review the recent studies on the development of magnetic microbubbles and their future applications.
