Active control of bubble liposome through artificial capillary by using matrix array transducer

We have ever reported our attempts to control microbubbles (MBs) using the primary and secondary acoustic force for active control in artificial blood vessels. Recently, we have demonstrated active path selection of MBs by using a matrix array transducer to produce multiple focal points. On the other hand, bubble liposomes (BLs) have an advantage in easily modifying targeting ligand. However, considering that BLs are several hundred nanometers in diameter, there were some difficulties in controllability of bubbles in blood flow under ultrasound exposure, since acoustic forces are less affected to these small bubbles. In this study, we used the liposomes (BLs) entrapping perfluoropropane gas with the average diameter of 500 nm and applied it to control the behavior in an artificial blood vessel. First, we observed aggregates formation of BLs in static water by secondary acoustic force. Next, we investigated the BLs control in multi-bifurcated flow by using a matrix array transducer. As a result, the streaming of BLs was viscously propelled to a desired path. BLs are much tied each other because of surface interaction of the lipid membrane and then caused a resistance to flow compare to MBs.