Niedert Elizabeth E, Bi Chenghao, Adam Georges, Lambert Elly, Solorio Luis, Goergen Craig J, Cappelleri David J
Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA.
School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA.
Micromachines (Basel). 2020 Sep 17;11(9):861. doi: 10.3390/mi11090861.
A microrobot system comprising an untethered tumbling magnetic microrobot, a two-degree-of-freedom rotating permanent magnet, and an ultrasound imaging system has been developed for in vitro and in vivo biomedical applications. The microrobot tumbles end-over-end in a net forward motion due to applied magnetic torque from the rotating magnet. By turning the rotational axis of the magnet, two-dimensional directional control is possible and the microrobot was steered along various trajectories, including a circular path and P-shaped path. The microrobot is capable of moving over the unstructured terrain within a murine colon in in vitro, in situ, and in vivo conditions, as well as a porcine colon in ex vivo conditions. High-frequency ultrasound imaging allows for real-time determination of the microrobot's position while it is optically occluded by animal tissue. When coated with a fluorescein payload, the microrobot was shown to release the majority of the payload over a 1-h time period in phosphate-buffered saline. Cytotoxicity tests demonstrated that the microrobot's constituent materials, SU-8 and polydimethylsiloxane (PDMS), did not show a statistically significant difference in toxicity to murine fibroblasts from the negative control, even when the materials were doped with magnetic neodymium microparticles. The microrobot system's capabilities make it promising for targeted drug delivery and other in vivo biomedical applications.
一种微型机器人系统已被开发出来，用于体外和体内生物医学应用，该系统包括一个无系绳翻滚磁性微型机器人、一个两自由度旋转永磁体和一个超声成像系统。由于旋转磁体施加的磁转矩，微型机器人会翻滚前进。通过转动磁体的旋转轴，可以实现二维方向控制，微型机器人能够沿着各种轨迹行驶，包括圆形路径和P形路径。该微型机器人能够在体外、原位和体内条件下在小鼠结肠的非结构化地形上移动，也能在离体条件下在猪结肠上移动。当微型机器人被动物组织光学遮挡时，高频超声成像可以实时确定其位置。当微型机器人负载荧光素时，在磷酸盐缓冲盐水中，大部分负载在1小时内被释放。细胞毒性测试表明，微型机器人的组成材料SU-8和聚二甲基硅氧烷（PDMS），即使在材料中掺杂了磁性钕微粒，对小鼠成纤维细胞的毒性与阴性对照相比也没有统计学上的显著差异。微型机器人系统的这些能力使其在靶向给药和其他体内生物医学应用方面具有广阔前景。
