聚3,4乙烯二氧噻吩修饰的新型碳纳米管纤维电极及其电化学性能评价

PEDOT-modified Novel Carbon Nanotubes Fiber Electrode and Its Electrochemical Performance Evaluation

目的 植入式脑机接口在神经疾病的治疗方面已经得到了广泛应用,治疗的效果依赖于与神经组织接触的电极。与刚性材料制作的电极相比,碳基微纤维电极尺度小、生物兼容性好、组织炎症反应小,可以减少植入后的异物反应,改善神经记录信号的信噪比,可以长期保持稳定的电极特性。方法 本文设计了一种柔性碳纳米管(carbon nanotubes,CNTs)纤维电极的修饰方法,该方法采用电化学聚合的方式可以将聚3,4-乙烯二氧噻吩(poly(3,4-ethylenedioxythiophene),PEDOT)薄膜沉积到CNTs纤维电极上,作为微电极涂层。为了证明修饰涂层在电极表面具有良好的机械稳定性,对修饰电极进行了超声处理。此外,本文将PEDOT薄膜沉积到ITO玻璃上,评价了PEDOT薄膜的生物相容性。结果 恒电流方式在CNTs纤维电极表面沉积的PEDOT涂层降低了电极的电化学阻抗,提高了电极的电化学性能,且PEDOT沉积的时间越长阻抗减少的幅度越明显。对电极进行超声处理后,电极的电化学阻抗没有产生显著变化,说明超声处理后PEDOT涂层剥离较少,证明了修饰涂层在电极表面具有良好的机械稳定性。最后,细胞实验表明,PEDOT薄膜具有与ITO导电玻璃相当的细胞相容性。结论 PEDOT薄膜可以提高CNTs纤维电极的稳定性,有望提高脑机接口系统的寿命和可靠性,具有应用于长时间记录神经电信号的前景。

Objective Implantable brain computer interface has been widely used in the treatment of neurological diseases, where the effectiveness of the treatment depends on the electrodes in contact with the neural tissue. Compared with the electrodes made of rigid materials, the carbon based microfiber electrodes have small scale, good biocompatibility and small tissue inflammatory reaction. It can reduce the foreign body reaction after implantation, improve the signal-to-noise ratio of nerve recording signals, and maintain stable electrode characteristics for a long time. Methods A modification method of flexible carbon nanotubes(CNTs) fiber electrode was designed in this paper. Poly(3,4-ethylenedioxythiophene)(PEDOT) films can be deposited on CNTs fiber electrode as microelectrode coating by electrochemical polymerization. In order to prove that the modified coating has good mechanical stability on the electrode surface, we treated the modified electrode with ultrasonic treatment. In addition, PEDOT films were deposited on ITO glass to evaluate the biocompatibility of PEDOT films. Results PEDOT coating deposited on the surface of CNTs fiber electrode in constant current mode reduced the electrochemical impedance of the electrode and improved the electrochemical performance of the electrode. The longer PEDOT deposition time, the more obvious the reduction of impedance. After ultrasonic treatment, the electrochemical impedance of the electrode did not change significantly, indicating that there was less peeling of PEDOT coating after ultrasonic treatment, which proved that the modified coating had good mechanical stability on the electrode surface. Finally, cell experiments show that PEDOT film has the same cell compatibility as ITO conductive glass. Conclusion PEDOT film can improve the stability of CNTs fiber electrode, and is expected to improve the service life and reliability of brain computer interface system. It has the prospect of application in long-term recording of neuroelectrical signals.