Shock Dynamic Study of Laser Ablation Induced Drug Delivery

在东北大学冲击波综合研究中心，我们的目标是将冲击波现象应用于医学。我们已经完成了体外冲击波碎石术，现在正在开发脑血栓血运重建系统，预计将在不久的将来完成。在这些课题中，冲击波总是扮演着重要的角色 *。当调Q激光束在金属箔表面聚焦一个点时，瞬间从该点喷射出等离子体云，作为其反应，在金属箔内部产生冲击波，该冲击波传播并从另一表面反射。等离子体的形成被称为激光烧蚀。反射波是一种膨胀波，其结果是箔以2至5 km/s的速度瞬时膨胀。当小颗粒附着在金属表面时，这些颗粒会在激光束照射的瞬间以如此高的速度喷射出来。这一原理已被应用于加速干燥 ...更多信息 药物颗粒或金属颗粒 * 的数量级为1微米左右进入人体组织。我们使用Q开关Nd：YAG激光聚焦在5 mm厚的玻璃板表面上，该玻璃板背衬有0.1 mm的铝箔，铝箔上附着有钨或金颗粒。我们测量到粒子喷射速度在1到2 km/s的数量级。将这些颗粒注射到琼脂糖细胞、小鼠肝脏和小鼠皮肤上，我们测量了这些颗粒的穿透深度，发现单个材料的最大穿透深度约为6 mm。这类小颗粒的自由飞行属于高超声速Stokes流，在气体动力学领域尚未得到认真的讨论。我们已经开发了数值方案来估计粒子自由飞行以及渗透到软组织中。我们已经用这种方法检查了在液体溶液中渗透到细胞系中，并观察到一微米的钨颗粒漂亮地渗透到细胞中。基于这些基础研究，我们得出结论，这种方法是上级现有的机械基因传递系统，所以强大和紧凑，它可以重新设计为一种治疗设备。我们相信我们已经完成了我们最初提出的主要目标。少

In the Interdisciplinary Shock Wave Research Center, Tohoku University, we have aimed to apply the shock wave phenomena to medicine. We have already finished the extracorporeal shock wave lithotripsy and now are working for the development of system for revascularization of cerebral thrombosis, which is expected to be completed in very near future. In these topics a shock wave plays always an important role*. When a Q-switched laser beam focused a spot on a metal foil surface, instantaneously a plasma cloud ejected from the spot and as its reaction a shock wave is generated inside the metal foil which propagate and reflected from the other surface. The plasma formation is called laser ablation. The reflected wave an expansion one and as a result of it the foil is instantaneously bulged at 2 to 5 km/s. When small* particles are attached on the metal surface these would be ejected at such a high speed at the moment laser beam irradiation. This principle has been applied to accelerate dry … More drug particles or metal particles* of the order of magnitude of one micron or so into human tissue. We have used Q-switched Nd:YAG laser focused on the surface of a 5 mm thick glass plate backed up with 0.1 mm this aluminum foil on which tungsten or gold particles were attached. We measured the particle ejection speed to be in the order of magnitude of 1 to 2 km/s. Injecting these particles against agarose cell, mouse liver, and mouse skin, we measured penetration depths against these and found the maximum penetration depth was about 6 mm for individual materials. The free flight of such small particles belongs to hypersonic Stokes flow which has never be discussed seriously in the field gas dynamics. We have developed numerical scheme to estimate particle free flight as well as penetration into soft tissues. We have examined with this method the penetration into cell lines in liquid solution and observed a beautiful penetration of a one micron tungsten particle into a cell. Based on these basic studies we concluded that this method is superior to the existing mechanical gene delivery systems and so robust and compact that it can be redesigned as a therapeutic device. We believe we have accomplished our main goal which we proposed at first. Less