Formation of Bio-interface by Patterned Negative Ion Implantation Treatment

(1)负离子注入形成神经细胞网络：将碳负离子注入聚苯乙烯PS、硅橡胶SR、聚酰亚胺PI等多种聚合物材料中，旋转涂覆在玻璃上，通过87个狭缝的图案掩模(孔径50μm)注入。研究了神经细胞PC-12h(大鼠肾上腺嗜铬细胞瘤神经细胞)在不同碳离子注入聚合物上的附着特性。在离子能量大于10keV，剂量大于3×10~(-15)离子/cm~(-2)的条件下，细胞对聚苯乙烯和硅橡胶的离子注入区域表现出选择性附着。另一方面，他们没有在聚酰亚胺上显示它。然而，在5keV的低能量条件下，神经细胞在聚酰亚胺植入区域表现出选择性附着。来自细胞体的突起也显示出对PS、SR和PI以及细胞附着特性的选择性延伸。(2)聚合酶…上润湿性和蛋白质吸附的表面控制更多的负离子注入比：我们用水中的气泡法和空气中的水滴法测量了水在离子注入的各种聚合物上的收缩角。我们发现，植入的表面在水和培养介质中需要数小时才能稳定其表面状态。因此，气泡法是评价细胞贴壁性能的合适方法。碳负离子注入使表面接触角减小，即变得亲水，聚苯乙烯约为10°，硅橡胶约为20°。另一方面，注入后聚酰亚胺的接触角增加了约15°，即疏水性。在蛋白质-PBS溶液中浸泡后，还检测了神经生长因子NGF、成纤维细胞生长因子和明胶的蛋白质吸附。XPS分析表明，注入C的PS和SR表面的氮量远高于未注入的区域。这意味着C-植入的PS和SR能够吸附蛋白质，从而导致神经细胞和轴突的选择性附着。(3)选择性附着在PS的C-植入区的细胞对PS膜下导电耦合电极板的外加电脉冲的反应：我们研究了导电偶联板的外加电脉冲对附着的细胞突起的生长。细胞突起优先向正电脉冲电极生长，而不是另一电极。这意味着人工控制细胞与轴突之间的连接模式是可能的。用斑块法证实神经细胞的兴奋是由电感耦合的外加电脉冲引起的。结果表明，利用我们开发的负离子注入方法，能够形成生物神经系统与外部半导体电路之间的生物界面。较少

(1)Formation of nerve cell network by negative ion implantation :We implanted carbon negative ions into various polymer materials of polystyrene PS, silicone rubber SR and polyimide PI, which were spin-coated on glass, through a pattern mask with 87 slits (aperture width of 50μm). Attachment properties of Nerve cells PC-12h (rat adrenal pheochromocytoma nerve cell) were investigated on the various C-implanted polymers. Under conditions of ion energy more then 10 keV and dose more than 3x10^<15> ions/cm^2, the cells showed selective attachment on ion-implanted region for polystyrene and silicone rubber. On the other hand, they did not show it on the polyimide. Under the low energy condition of 5 keV, however, nerve cells showed the selective attachment on implanted area of polyimide. Neurite from the cell body also showed selective extension over the implanted area for PS,SR, and PI as well as cell attachment properties.(2)Surface controls of wettability and protein adsorption on polyme … More rs by negative ion implantation :We applied to measure the contract angle of water on ion-implanted various polymers by bubble method in water as well as water-drop method in air. We found that the implanted surface required many hours in water and culture medium to stabilize it surface state. Therefore, the bubble method is suitable way for evaluation of cell attachment properties. Decrease of contact angle on the surface, i.e., becoming hydrophilic was obtained were by carbon negative ion implantation : about 10° for polystyrene and 20° for silicone rubber. On the other hand, the polyimide showed an increase of contact angle, i.e., hydrophobic, about 15° by implantation. Protein adsorption was also tested for nerve growth factor NGF,FGF, and gelatin after dipping in protein-PBS solution. Nitrogen amount (from the protein) on C-implanted PS and SR surface was detected much more than that on un-implanted area by XPS analysis. This means C-implanted PS and SR were able to adsorb protein and then result selective attachment of nerve cells and neurite.(3)Response of cells selectively attached on C-implanted area of PS against externally applied electric impulse from conductive coupling electrode pad below the PS film :We investigate the outgrow of neurite from attached cells by externally applied electric impulse from conductive coupling pad. We obtained preferential outgrow of neurite from cells toward positive electric pulse electrode rather than the other electrode. This means the possibility of artificially control of connecting pattern among cells with axons. By using patch clump method, excitation of nerve cells was confirmed to be induced by the externally applied electric impulse with inductive coupling. As a result, the bio-interface between bio-nerve system and external semiconductor circuit was able to be formed by using our developed negative ion implantation method. Less