Abstract
We have ever studied dynamic control of microbubbles making use of acoustic radiation forces for future drug delivery system (DDS). Because ultrasound has great advantages of percutaneous control, there are possibilities of induction, aggregation and destruction of microbubbles in human body. Furthermore, using ligand-modified microbubbles, higher potential DDS, which combines physical and chemical effects, should be realized. Objective of this study is to confirm the possibility of dynamic control of microbubbles in blood flow. We have prepared the experimental setup including a water bath, an echography for observation, and a rabbit to utilize its bifurcation of blood vessel in ear. An ultrasound transducer with central frequency of 5 MHz was positioned to focus at the bifurcation point, which diameter and flow velocity were less than 0.5 mm and 500 mm/s, respectively. The result showed that microbubbles were induced to the objective path after the bifurcation with the inducing index of more than 70%, which was calculated from brightness variation in echograms.
