Khalifa Adam, Weigand-Whittier Jonah, Farrar Christian T, Cash Sydney
Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States.
Department of Radiology, Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Harvard Medical School, Boston, MA, United States.
Front Neurosci. 2021 Oct 5;15:738589. doi: 10.3389/fnins.2021.738589. eCollection 2021.
Wirelessly powered microdevices are being miniaturized to improve safety, longevity, and spatial resolution in a wide range of biomedical applications. Some wireless microdevices have reached a point where they can be injected whole into the central nervous system. However, the state-of-the-art floating microdevices have not yet been tested in chronic brain applications, and there is a growing concern that the implants might migrate through neural tissue over time. Using a 9.4T MRI scanner, we attempt to address the migration question by tracking ultra-small devices injected in different areas of the brain (cortico-subcortical) of rats over 5 months. We demonstrate that injectable microdevices smaller than 0.01 mm remain anchored in the brain at the targeted injection site over this time period. Based on CD68 (microglia) and GFAP (astrocytes) immunoreactivity to the microdevice, we hypothesize that glial scar formation is preventing the migration of chronically implanted microdevices in the brain over time.
无线供电的微型设备正在不断小型化，以提高广泛生物医学应用中的安全性、使用寿命和空间分辨率。一些无线微型设备已经发展到可以整体注入中枢神经系统的程度。然而，目前最先进的浮动微型设备尚未在慢性脑应用中进行测试，并且人们越来越担心随着时间的推移，植入物可能会在神经组织中迁移。我们使用一台9.4T磁共振成像（MRI）扫描仪，试图通过跟踪在大鼠大脑不同区域（皮质-皮质下）注射的超小型设备长达5个月来解决迁移问题。我们证明，在此时间段内，小于0.01毫米的可注射微型设备仍固定在大脑中的靶向注射部位。基于对微型设备的CD68（小胶质细胞）和GFAP（星形胶质细胞）免疫反应，我们推测随着时间的推移，胶质瘢痕形成可防止慢性植入大脑的微型设备迁移。
