Elucidation of Disintegration Mechanism of Microcapsules including a Gas Bubble and Nano-particles for Drug Delivery in Blood Flows Using Underwater Shock Waves

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In this study, our aim is to investigate this mechanism and apply the shock wave technology to disintegrate cell in the bioprocess industry and medical field such as Drug Delivery Systems (DDS). In this project, especially, the following important things for applying to DDS were investigated(A-1) Stimulus of the capsule and the cell near the arterial wall and thrombus in the shock wave DDS.(A-2) Establishment of disintegration of microcapsule and stimulus of the cell by shock waveThe results about these topics are obtained as follows;(A-1) The stimulus of shock waves on the cell increases the growth rate of the cell number in case of endothelial cells. Although this result shows possibility of decreasing the effects of anti-cancer, it is possible to optimize two parameters such as disintegration and cell-growth because the growth rate is dependent on the rise frequency and amplitude of pressure wave (shock wave)(A-2) To apply theoretical model of the shock wave propagation to the cell, … More the cell model was composed of three structures such as the surrounding fluid, cell membrane and internal fluid. Using these models, the stress and pressure wave on the membrane and in the cell were analyzed in case of working underwater shock wave on the cell. As a result, the higher the rising frequency becomes high, the larger the stress wave on the cell increases. Then it was found that the effect of frequency on the stimulus is high.For the development of generating shock wave method, the following two things are investigated as the actual application;(B-1) Generation of shock wave using Laser(B-2) Development of small scale microcapsule including a gas bubble and measurement of their mechanical properties.The results about these topics are obtained as follows;(B-1) The generation method of shock wave using Yag Laser was established, but energy loss in the part of optical coupling between optical fiber and lens is high and the stability of shock wave generation was not good. So the method to introduce the shock wave in the test water tank will be changed, then the laser beam will be directly to the water tank system.(B-2) The special microcapsules composed of gas bubble, liquid, capsule membrane can be obtained, and the diameter size of them is 20-30 μm. This size is 30% of the previous investigation up to 2003, and it is found that these size is applicable to use as bladder DDS in human body. Less