Active path selection of fluid microcapsules by acoustic radiation force in the artificial blood vessel

Abstract

Microcapsules of µm order collapse themselves after ultrasound emission. Recently, this technique attracts attention to apply to the gene delivery because virus vector is not necessary. However, it has been limitation to enhance the efficiency of medication because capsules suspension diffuses after the injection, where motion of capsules in blood flow cannot be controlled. To affect behavior of microcapsules, acoustic radiation force was introduced. Then we have detected the local change of microcapsules density by producing acoustic radiation force in the artificial blood vessel. Furthermore, we estimated theoretically condition for active path selection of capsules at the bifurcation in the artificial blood vessel. We observed the difference of density in capsules according to the acoustic radiation force and the produced point. Comparing the experimental results with theoretical equations, the condition for active path selection is calculated from acoustic radiation force and fluid resistance of capsules. It showed a possibility to control capsules direction and to lead to an objective point in blood vessel.