CPS: Medium: Collaborative Research: Wireless Magnetic Millibot Blood Clot Removal and Navigation in 3-D Printed Patient-Specific Phantoms using Echocardiography

据估计，每年有10万至30万美国人死于人体血液凝块。目前的治疗方法依赖于分解血栓的药物，这种药物可以与机械改变血栓的外科手术相结合。然而，溶栓药物和手术都与意想不到的不良事件有关。本项目设计和研究微型磁力游泳器，作为这些治疗的微创替代方案。这些设备是毫米级的物体，具有螺旋形状，并包含一个小的永久磁铁。旋转磁场被用来遥控游泳者。磁场使游泳者旋转，螺旋形状将旋转运动转化为推进力(很像船的螺旋桨)。游泳者可以通过改变外加磁场的方向来控制方向。它们可以沿着预先定义的3D路径在液体中精确导航，并可能在血液中导航到血液凝块。旋转运动可以用来磨损血栓并恢复适当的血流。本项目引入了新的生物医学范例，并研究了在复杂、时变的环境中磁泳者的健壮的高速无绳操纵。它需要多种游泳者设计，创新的控制器，以及集成的动态传感模式。该项目分为三个协同目标。首先，必须为游泳运动员建立流体动力学模型并进行实验验证。这个模型将被用来优化游泳者的几何形状。其次，将建立一个健壮的游泳者控制器。控制器必须能够补偿动脉中存在的可变血流量。将使用超声波扫描仪跟踪游泳者的位置，并获得有关其环境的有用信息。例如，游泳者的速度可以用来推断血流速度。最后，将通过体外实验来研究几种外科手术的可行性。3D导航和清除人体血液凝块将在人体心脏模型内进行。几名游泳运动员的最终执行者也将接受测试。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Human blood clots kill an estimated 100,000 to 300,000 Americans each year. Current treatments rely on medications that break down clots, which can be combined with a surgical procedure that mechanically alters the clot. However, clot-busting medications and surgery are both linked to unintended adverse events. This project designs and studies miniature magnetic swimmers as a minimally invasive alternative to these treatments. These devices are millimeter-scale objects that have a helical shape and contain a small permanent magnet. A rotating magnetic field is used to remotely control the swimmers. The field makes the swimmer rotate and the helical shape converts the rotational movement into a propulsive force (much like a boat's propeller). The swimmers can be steered by changing the orientation of the applied magnetic field. They can precisely navigate within liquids along pre-defined 3D paths and could potentially navigate within the bloodstream toward a blood clot. The rotational movement can be used to abrade the clot and restore an appropriate blood flow.This project introduces new biomedical paradigms and investigates the robust high-speed tetherless manipulation of magnetic swimmers in complex, time-varying environments. It requires multiple swimmer designs, innovative controllers, and integrated, dynamic sensing modalities. The project is divided into three synergetic objectives. First, a fluid-dynamics model for the swimmer must be created and validated experimentally. This model will be used to optimize the swimmer's geometry. Secondly, a robust swimmer controller will be built. The controller must be able to compensate for the variable blood flow present in the arteries. An ultrasound scanner will be used to track the position of the swimmer and obtain useful information about its environment. For example, the velocity of the swimmer can be used to infer the blood flow velocity. Finally, the feasibility of several surgical procedures will be studied via ex-vivo experiments. 3D navigation together with the removal of human blood clots will be performed inside a human heart phantom. Several swimmers end effectors will also be tested.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.