报告题目：Functional Magnetic Nanomotors to Improve Ischemic StrokeTreatment
Yiping Zhao教授，国际光学工程学会会士（SPIE Fellow）和美国真空学会会士（AVS Fellow），美国佐治亚大学物理和天文学系杰出研究终身教授（Distinguished Research Professor）。1991年毕业于北京大学电子系获学士学位，1994年毕业于中科院半导体所获得物理学硕士学位，1999年于美国伦斯勒理工学院获得物理学博士学位。Zhao教授先后主持美国国家科学基金、NIH科学基金、农业部和能源部科研项目等30余项，发表学术论文300余篇，出版专著3部，拥有授权美国发明专利12件。目前研究领域为纳米薄膜制备和表征、等离子纳米结构、纳米马达、化学和生物传感器、氢储能材料和纳米光子晶体等。
The treatment of ischemicstroke remains a daunting task as few therapeutic strategies have proven to beeffective. Systemic thrombolysis with intravenous tissue plasminogen activator(tPA) remains the only proven treatment to improve clinical outcome of patientswith acute ischemic stroke. But because of an increased risk of hemorrhagebeyond 4.5 hours after onset of stroke, only certain stroke patients (1-2%) canbenefit from tPA treatment. Current limitations of intravascular thrombolysisare primarily due to the inefficient/ineffective penetration of thesystemically circulating tPA into the thrombus core. To improve tPA-inducedthrombolysis and recanalization rates, we have developed a new strategy byincorporating rotary magnetic iron oxide (Fe3O4)-nanorodspowered by an external magnetic field with the tPA delivery. Once the nanorodsencounter the blood clot in the artery, it could not only improve the masstransport of the tPA-clot reaction, but also could mechanically disrupt theclot network to make a larger opening in the clot. Additionally, when magneticnanorods are covalently bound to tPA with retained enzyme activity, the tPAfunctionalized magnetic nanorods can target to the blood clot in vivo under theguidance of an external magnet and tPA can subsequently be efficientlydelivered at the site of embolism at high concentration to facilitatethrombolysis. Thus, an efficient tPA delivery system to the brain incombination with magnetic nanorods overcomes the limitations of current therapywith tPA alone. In a mouse model, we show that with two orders of lessconcentration of tPA on tPA-magnetic nanorod injection, it takes less than 1/3time to lyse the blood clot, compared to that of tPA injection alone. In thistalk, I will discuss the synthesis, functionalization of the magnetic nanorods,the physical and chemical mechanism of the improved thrombolysis, and theresults from both the in vitro and animal tests as well as future challenges.