MEMS Umbrella-Shaped Actuator with Active Structure for Medical Applications

本研究的目的是设计、制造和测试一种伞状微致动器，用于中风治疗中的血栓回收。该方法是：1)根据血凝块的特性设计致动器；2)采用集成微纳加工技术制备致动器；3)通过体外血管模型验证和提高驱动器的功能和可靠性。智能优势：该驱动器由由新型压电纳米纤维精确控制的主动结构组成。所提出的致动器的功能原理是独特的，因为它可以提供一个动态剪切力在血管动脉的血凝块。由于剪切变薄现象，这种剪切力可以微调，以促进血凝块与血管动脉壁的分离，从而实现完全取出，同时最大限度地降低动脉损伤的风险。这项研究将为纳米材料的压电响应以及血凝块的力学行为领域提供新的基础知识。更广泛的影响：中风是美国第三大死亡原因，动脉血流阻塞占所有中风的83%。如果成功，这项研究将带来一种安全可靠的中风治疗方法，可以在几分钟内为阻塞的血管动脉提供再通。基于这项研究的教育材料将通过各种推广计划和现有的NSF纳米技术本科教育计划，以不同的形式在不同层次的课程中实施。

The objective of this research is to design, fabricate and test an umbrella-shaped microactuator for thrombus retrieval in stroke therapy. The approach is to 1) design the actuator based on the properties of blood clots; 2) fabricate the actuator using an integrated micro/nanofabrication technique; and 3) demonstrate and improve the functionality and reliability of the actuator through in an in vitro vascular model. Intellectual Merit: The proposed actuator consists of active structures that are precisely controlled by novel piezoelectric nanofibers. The functional principle of the proposed actuator is unique in that it can provide a dynamic shear force on blood clots in vascular arteries. This shear force can be fine-tuned to facilitate the separation of the blood clot from the wall of the vascular artery due to the shearing-thinning phenomenon, thus enabling complete retrieval while minimizing the risk of damage to the arteries. This research will contribute new fundamental knowledge in the areas of piezoelectric response of nanomaterials as well as the mechanical behavior of blood clots.Broader Impact: Stroke is the third leading cause of death in the U.S, with blockage of arterial blood flow accounting for 83% of all strokes. If successful, this research will lead to a safe and reliable stroke therapy providing recanalization of blocked vascular arteries on the order of minutes. Educational materials based on this research will be implemented in courses at different levels and in different formats through various outreach programs and an existing NSF Nanotechnology Undergraduate Education program.