Carbon Nanotube Field Emission Microbeam Array for Single Cell Irradiation

描述（由申请人提供）：由于我们缺乏对细胞辐射反应背后的分子事件的透彻理解，阻碍了放射治疗和辐射防护领域的进步。其中一个原因是缺乏在非常小的时间和空间尺度上进行此类研究所需的专门仪器。当需要将一个或几个细胞的辐射反应与整个细胞群的辐射反应区分开来时，无法在微观尺度上传递辐射尤其有害。许多人认为，长期的辐射后遗症——可能几十年都不会显现出来——是由信号通路、DNA损伤评估和修复中的事件调控的，所有这些都发生在辐射后的最初几分钟内。为了提供急需的新型细胞辐照技术，我们提出了基于纳米技术的微束阵列装置，该装置可以在体外对单个细胞进行低LET电子辐照的同时进行实时显微观察。基于碳纳米管独特的场发射特性，该装置从其10,000个单独控制的微光束产生像素发出辐射。辐射传输可以是空间离散的或均匀的，连续的或脉冲的，时间尺度小于微秒。最重要的是，从辐射安全的角度来看，微光束对操作员造成的辐射暴露可以忽略不计，因此设备不需要特殊的屏蔽。一旦研制成功，这种培养皿大小的微束装置可用于许多实验室研究新的放射增敏剂和放射保护剂的分子靶标。具体而言，在本提案中，我们建议1)确定用于细胞研究的微束设备的规格；2)制作并调试单像素微束器件原型；3)在特定的体外实验中论证微束装置的可行性，包括分析EGFR、Ras和MEKK通路的时空调控；4)研制了一种多像素微束阵列器件。再加上使用新的生物标记和细胞成像技术，该装置有望为识别和操纵辐射反应开辟新的研究能力——这对改进癌症治疗、保护执行深空任务的宇航员、保护应急反应人员和公众免受辐射恐怖主义的影响至关重要。

DESCRIPTION (provided by applicant): Advancements in the fields of radiation therapy and radiation protection are hindered by our lack of a thorough understanding of molecular events that underlie the radiation response of cells. One reason is the shortage of specialized instrumentation required by such studies on very small time and spatial scales. The inability to deliver radiation on microscopic scale can be especially detrimental when the radiation response of one or a few cells needs to be distinguished from that of an entire cell population. Many believe that long term radiation sequelae-that may not manifest themselves for decades-are regulated by events in signaling pathways, DNA damage assessment and repair, all occurring within the first few minutes following irradiation. To provide the much needed new cellular irradiation technology we propose to develop nanotechnology based microbeam array devices that can deliver low LET electron irradiation to individual cells in vitro simultaneous with real-time microscopic observation. Based on the unique field emission property of carbon nanotube the device delivers radiation from its 10,000 individually controlled microbeam-producing pixels. Radiation delivery can be spatially discreet or uniform, continuous or pulsed at a less than microsecond time scale. Most important from a radiation safety standpoint, the microbeams cause negligible radiation exposure to the operator, thus the devices do not require special shielding. Once developed, the Petri-dish- sized microbeam devices can become available to many laboratories to study molecular targets for the development of new radiosensitizers and radioprotectors. Specifically, in this proposal we propose to 1) determine specifications for the microbeam devices for cellular research; 2) perform fabrication and commissioning of a prototype single pixel microbeam device; 3) demonstrate the feasibility of the microbeam device in specific in vitro experiments including analyzing spatio-temporal regulation of EGFR, Ras, and MEKK pathways; and 4) develop and fabricate a multi-pixel microbeam array device. Together with the use of new biomarkers and cellular imaging techniques, the proposed device promises to open up new research capabilities for the identification and manipulation of radiation responses - an understanding vital to improvements in cancer therapy, the protection of astronauts on deep-space missions, and the protection of emergency-responders and the public against radiological terrorism.