Gutowski Stacie M, Templeman Kellie L, South Antoinette B, Gaulding Jeffrey C, Shoemaker James T, LaPlaca Michelle C, Bellamkonda Ravi V, Lyon L Andrew, García Andrés J
Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, 30332-0363; Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332-0363.
J Biomed Mater Res A. 2014 May;102(5):1486-99. doi: 10.1002/jbm.a.34799. Epub 2013 Jun 25.
The performance of neural electrodes implanted in the brain is often limited by host response in the surrounding brain tissue, including astrocytic scar formation, neuronal cell death, and inflammation around the implant. We applied conformal microgel coatings to silicon neural electrodes and examined host responses to microgel-coated and uncoated electrodes following implantation in the rat brain. In vitro analyses demonstrated significantly reduced astrocyte and microglia adhesion to microgel-coated electrodes compared to uncoated controls. Microgel-coated and uncoated electrodes were implanted in the rat brain cortex and the extent of activated microglia and astrocytes as well as neuron density around the implant were evaluated at 1, 4, and 24 weeks postimplantation. Microgel coatings reduced astrocytic recruitment around the implant at later time points. However, microglial response indicated persistence of inflammation in the area around the electrode. Neuronal density around the implanted electrodes was also lower for both implant groups compared to the uninjured control. These results demonstrate that microgel coatings do not significantly improve host responses to implanted neural electrodes and underscore the need for further improvements in implantable materials.
植入大脑的神经电极的性能常常受到周围脑组织宿主反应的限制,包括星形胶质细胞瘢痕形成、神经元细胞死亡以及植入物周围的炎症。我们将保形微凝胶涂层应用于硅神经电极,并在大鼠大脑中植入后检查了宿主对微凝胶涂层电极和未涂层电极的反应。体外分析表明,与未涂层的对照相比,星形胶质细胞和小胶质细胞对微凝胶涂层电极的粘附显著减少。将微凝胶涂层电极和未涂层电极植入大鼠大脑皮层,并在植入后1周、4周和24周评估植入物周围活化的小胶质细胞和星形胶质细胞的程度以及神经元密度。微凝胶涂层在后期时间点减少了植入物周围星形胶质细胞的募集。然而,小胶质细胞反应表明电极周围区域存在持续的炎症。与未受伤的对照相比,两个植入组植入电极周围的神经元密度也较低。这些结果表明,微凝胶涂层并不能显著改善宿主对植入神经电极的反应,并强调了对可植入材料进一步改进的必要性。