脑起搏器通过埋植在胸前的刺激器向植入大脑特定靶点的电极发送电脉冲来治疗大脑疾病，是帕金森病、癫痫、抑郁等疾病的首选外科疗法，对于药物成瘾等治疗也有潜在的临床价值。电极直接与脑组织接触，是脑起搏器系统中的核心部分。而电极在磁共振成像下应用存在不相容的问题，限制了脑起搏器的应用。脑起搏器开发技术难度高，长期为美国垄断。本文全面解决了电极的设计、工艺、测试以及可靠性等问题，实现电极开发并批量应用于临床，使电极制造在国内首次突破并达到了长期临床应用水平。在此基础上结合碳纳米管宏观体，提出用碳纳米管线制作电极触点以及用碳纳米管薄膜包裹电极的方法，对电极在磁共振成像应用中存在的关键问题进行了研究。首先提出用碳纳米管线取代传统铂铱制作电极触点，通过体外测试和动物实验分析了其电化学特性，表明碳纳米管具有优良的电极界面特性，如电荷存储能力是铂铱的20多倍等，且性质稳定。建立了等效电路模型，分析了阻抗成分，表明其是理想的刺激电极。碳纳米管线电极的优良界面性能也为电极向小型化等方向发展提供了更大的空间。研究了磁共振成像环境下碳纳米管线电极的伪影现象，通过水模实验和大鼠植入实验，证实其可以改善铂铱电极的磁共振成像质量，伪影减小超过50%，这能显著提高磁共振成像对电极的定位精度等。通过实验和理论分析表明磁化系数差异是影响脑起搏器电极伪影的主要因素，也是新的电极触点图像特性得到改善的主要原因。磁共振成像使用的射频磁场可能引起电极尖端过度发热，是脑起搏器在磁共振成像中应用的最大安全隐患。本文在研究触点以及导线结构等因素影响的基础上，提出了采用碳纳米管薄膜包覆电极的方法，显著降低了电极在磁共振环境下发热问题。体模实验表明该方法最大可将发热程度降低90%以上，不仅有望解决脑起搏器在磁共振下的临床应用问题，同时将为脑科学的研究打开一扇窗口，对心脏起搏器等其他植入式器械也有显著的应用价值。最后通过细胞培养和最长12周的大鼠植入实验对碳纳米管宏观体材料的生物相容性进行了研究，表明其具有良好的生物相容性，初步验证了其作为长期植入材料的可行性。

Deep brain stimulation (DBS) is used to treat various brain related refractory diseases by delivering current pulses from stimulator buried in chest to specific brain targets through a lead implanted in situ. It’s the most preferred surgical therapy in treating Parkinson’s disease, epilepsy, depression and so on, and has great potential to treat diseases such as addiction clinically. The lead is a key component of DBS system which directly contacts with the brain tissue. And incompatible problems of the lead under magnetic resonance imaging (MRI) restrain the application of DBS.The development of DBS system is of high difficulty technically, and has been monopolized by the USA for a long time. This dissertation implemented the development of the DBS lead by overcoming problems in lead design, machining process, functioning test and reliability enhancement, etc., and the leads has been used in clinical trials in large quantity. This is the first time the homemade DBS lead reached the level for long-term clinical application. Then this dissertation studied several critical issues of the DBS lead under MRI, taking advantage of macroscopic carbon nanotube materials.Firstly, to overcome the insufficiency in interfacial capability of the traditional Pt-Ir electrode of the DBS lead, a novel electrode made by carbon nanotube yarns (CNTYs) is proposed and analyzed both in vitro and in vivo. The results demonstrated that the CNTY electrode possesses much larger charge storage capacity and lower impedance than the Pt-Ir one, and showed stability after continuously delivering electrical stimulus. And equivalent circuit models were established to fit the experimental impedance data, which suggested that the CNTY electrode exhibited characteristics of a porous structure, and charge transfer across the electrode interface was realized by capacitive charging and discharging. These properties promised much larger room for improvement of the DBS lead.Secondly, with in mind that MRI is getting more and more prevalent both in clinic and research, the imaging properties of the CNTY electrode under MRI were examined, and it was found that its artifact property was much better than Pt-Ir. Experiments in water phantom were conducted and a automatic algorithm was came up to quantitatively measure the size of the artifact. The results confirmed the superiority of the CNTY electrode over Pt-Ir on the artifact issue. The electrodes were then implanted into rat brains and consistent results were obtained. Further analysis suggested that the susceptibility difference is the dominant cause to artifacts in MR images. And therefore the CNTY electrode might be beneficial by improving local image quality, increasing localization accuracy of the lead postoperatively and so on.Thirdly, radio frequency field in MRI may cause severe heating at the electrode of the lead, and hinders the utilization of DBS under MRI. A method to shield the lead body with carbon nanotube films (CNTFs) was brought up, and a series of phantom experiments were conducted that showed covering the lead with CNTF could reduce heating induced at the electrode under MRI as largely as more than 90% and the reduction effect was associated with the CNTF amount. These results demonstrated the obvious significance of this CNTF method in applications such as pacemaker leads and DBS fMRI research.Finally, the biocompatibility of the macroscopic carbon nanotube materials was studied both in vitro and in vivo. And it was found that cells could attach to the CNTY and grow well. After as long as 12 weeks’ implantation, the CNTY seemed to arouse even less foreign body response than Pt-Ir, and no obvious chronic inflammatory response was observed in the vicinity of the CNTY, suggesting macroscopic carbon nanotube materials is suitable for long-term implantation.