基于电子束曝光技术的微纳机器人的制备和控制研究

FABRICATION AND MOTION CONTROL OF MICRO AND NANOROBOTS BASED ON ELECTRON BEAM LITHOGRAPHY

江腾

11849348

硕士

机械工程

郑裕基

2020-06-04

2020-07-20

哈尔滨工业大学

深圳

随着纳米技术的发展与进步，使用微纳米机器人来实现靶向药物递送这一构想正逐渐变成现实。虽然微纳米机器人存在改善纳米药物递送系统的潜力，但目前的主要挑战之一是生物组织流体环境限制了较大尺度机器人的应用，而目前大多数研究都集中在微米与毫米尺度机器人的制备与功能开发上。因此为了推动微纳机器人的实际应用研究，本文通过电子束曝光技术来制备尺寸最小为400 nm的磁性纳米机器人。本研究采用二维L型的非手性结构设计制备磁性纳米机器人，满足了机器人的游泳形状要求。同时电子束曝光技术相比其它的微纳机器人制备方法如3D激光直写等大大简化了制备过程的复杂性。为了优化微纳机器人的游泳性能，本文详细研究了制备工艺参数对机器人样品重复性的影响。 本研究所使用的制备方法结合了电子束曝光、电子束蒸发和ICP（电感耦合等离子体）蚀刻技术来制备二维非手性L型微纳机器人。本研究使用定制的磁场控制系统来驱动非手性L型微纳机器人，在外部旋转磁场作用下微纳机器人能够将旋转运动转化为前进位移。为了测试微纳机器人的运动性能，本文通过成像系统记录机器人的运动姿态并通过图像跟踪算法分析其运动表现。此外，通过调整三维旋转磁场的方向，进行了非手性L型微纳机器人的3D运动控制。 本文通过对非手性L型微纳机器人制备流程和在旋转磁场下的的运动控制研究，得到了以下的成果：（1）在已有的设计理论基础上成功的制备出了最小边长为400 nm的非手性L型微纳机器人，并且对制备过程中的各个细节进行梳理，总结了剥离工艺中使用氢氧化钠调节过氧化氢溶液pH值来成功收集到L型微纳机器人的实验参数；（2）在旋转磁场下结合高倍显微镜的使用，对L型微纳机器人的运动姿态变化进行了分析，有利于确定最快前进速度下的L型微纳机器人的运动状态；（3）对L型微纳机器人在旋转磁场下的3D运动控制进行了初步的探索，该成果有望结合微纳机器人的集群控制，实现在生物体内的靶向运动操控。 本文的创新点在于提出了利用电子束曝光技术来制备微纳机器人，相较于目前该领域中的其他制备方法，如紫外光刻、激光直写和化学合成等方法，能够实现高精度和高产出的特点优势，这些特点对于靶向药物运输是非常重要的，同时该技术还为制备尺寸适合在生物体内运动的微纳机器人提供了方法。该研究通过制备简单二维形状的非手性L型微纳机器人，在旋转磁场中可实现三维运动，这项工作的成果将是微纳机器人迈向实用药物输送系统的重要一步。

With the development and progress of nanotechnology, the prospect of using micro and nanorobots to achieve targeted drug delivery becomes possible. Although nanorobots can potentially improve nano-drug delivery systems, one of the main challenges is the use of micro and nanorobots for in vivo drug delivery, that the biological tissue fluid environment limits the application of larger-scale robots, but most of the current research are focused on the preparation and functional development of micrometer and millimeter-scale robots. In order to solve this problem and promote the application of micro and nanorobots in vivo, this study uses electron beam lithography technology to fabricate achiral L-shape micro and nanorobots. The minimal planar geometry of the L-shape micro and nanorobots enable the use of nano-lithographic techniques to fabricate robots down to 400 nm. In this study, a two-dimensional L-shaped achiral structure was used to prepare the magnetic nanorobot, which met the swimming shape requirements of the robot. In order to optimize the swimming performance of the micro and nanorobots, the parameters in the fabrication process will be carefully studied to ensure the characteristics of consistency and repeatability. This study used a fabrication protocol that combines electron beam lithography, electron beam evaporation, and ICP etching technology to create two-dimensional achiral L-shape micro and nanorobots. A custom built magnetic control system was used to control the motion of the achiral L-shape micro and nanorobots. The micro and nanorobots were actuated using a rotating magnetic field. Furthermore, the swimming posture of the micro and nanorobots can be controlled. A tracking algorithm was used to study and analysis the motion of the micro and nanorobots. The 3D motion control of the achiral L-shape micro and nano robot was carried out by controlling the direction of the rotating field’s plane of rotation. This research focuses on the preparation process of the achiral L-shape micro and nanorobots and their motion control under a rotating magnetic field. The findings of this work are as follow: (1) Using the planar achiral geometry, micro and nanorobots with minimum side length of 400 nm has been successfully fabricated. The fabrication parameters is summarized in this report which include the use of sodium hydroxide in the stripping process to adjust the pH value of the hydrogen peroxide solution in order to successfully release the L-shape micro and nanorobots; (2) Combined with a high-power microscope and the magnetic controller, the movement postures of the L-shape micro and nanorobots was manipulated and analyzed; this is useful in determining the movement state of the L-shape micro and nanorobots which in turn helps controlling their velocity; (3) The 3D motion control of the micro-nano robot under the rotating magnetic field was performed and analyzed. The results herein will serve as a foundation for the future research on swarm control of micro and nanorobots in a simulated in vivo environment. The innovation of this research is as follow: the use of electron beam lithography technology to overcome the size limitation of magnetic microrobots. Compared with other preparation methods in the field, such as ultraviolet lithography, laser direct writing, or chemical synthesis, e-beam lithography offers high precision and high throughput fabrication at the nanoscale which is essential to drug delivery. This preparation method can prepare a micro-nano robot with a size that matches the movement in the living body. In this study, by preparing a simple two-dimensional achiral L-shape micro and nanorobots, three-dimensional motion can be achieved in a rotating magnetic field. The results of this work will enable the use of micro-nano robots to complete in vitro drug delivery, which is an important step towards a practical drug delivery system.

L型微纳机器人 非手性 电子束曝光技术 制备 运动控制

L shape micro-nano robot achiral electron beam lithography technology fabrication motion control

中文

联合培养

南方科技大学

江腾. 基于电子束曝光技术的微纳机器人的制备和控制研究[D]. 深圳. 哈尔滨工业大学,2020.