Electropolymerized Poly(3,4-ethylenedioxythiophene) (PEDOT) Coatings for Implantable Deep-Brain-Stimulating Microelectrodes
Electropolymerized Poly(3,4-ethylenedioxythiophene) (PEDOT) Coatings for Implantable Deep-Brain-Stimulating Microelectrodes
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DOI：
10.1021/acsami.9b03088
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发表时间：
2019-05-15
影响因子：
9.5
通讯作者：
Cicoira, Fabio
中科院分区：
文献类型：
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作者：
Bodart, Come;Rossetti, Nicolo;Cicoira, Fabio
导电聚合物由于其混合的电子-离子导电性和生物相容性而被广泛探索作为金属电极的涂层材料以改善神经信号记录和刺激。特别是，导电聚合物聚（3，4-乙撑二氧噻吩）（PEDOT）由于其高导电性和良好的电化学稳定性而成为生物医学应用的最佳候选者之一。用PEDOT涂覆金属电极已经显示出通过降低阻抗和增加电荷存储容量来增强电极的性能。然而，PEDOT涂覆的金属电极通常具有分层和稳定性的问题，导致器件性能和寿命降低。在这项工作中，我们能够在尖锐的铂铱记录和刺激神经电极上电沉积PEDOT涂层，并证明其机械和电化学稳定性。PEDOT：四氟硼酸盐的电聚合在三种不同的溶剂中进行：碳酸丙烯酯、乙腈和水。通过超声处理、磷酸盐缓冲溶液浸泡试验、高压灭菌和电脉冲处理来评价涂层的稳定性。用碳酸丙烯酯或乙腈制备的涂层具有优异的电化学稳定性，并且经受高压灭菌、长时间浸泡和电刺激而电化学性质没有重大变化。将刺激微电极植入大鼠体内，每天刺激，持续7天和15天。在体内监测的电化学性能表明，涂层和未涂层电极的刺激程序降低了阻抗。
Conducting polymers have been widely explored as coating materials for metal electrodes to improve neural signal recording and stimulation because of their mixed electronic-ionic conduction and biocompatibility. In particular, the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the best candidates for biomedical applications due to its high conductivity and good electrochemical stability. Coating metal electrodes with PEDOT has shown to enhance the electrode's performance by decreasing the impedance and increasing the charge storage capacity. However, PEDOT-coated metal electrodes often have issues with delamination and stability, resulting in decreased device performance and lifetime. In this work, we were able to electropolymerize PEDOT coatings on sharp platinum-iridium recording and stimulating neural electrodes and demonstrated its mechanical and electrochemical stability. Electropolymerization of PEDOT:tetrafluoroborate was carried out in three different solvents: propylene carbonate, acetonitrile, and water. The stability of the coatings was assessed via ultrasonication, phosphate buffer solution soaking test, autoclave sterilization, and electrical pulsing. Coatings prepared with propylene carbonate or acetonitrile possessed excellent electrochemical stability and survived autoclave sterilization, prolonged soaking, and electrical stimulation without major changes in electrochemical properties. Stimulating microelectrodes were implanted in rats and stimulated daily, for 7 and 15 days. The electrochemical properties monitored in vivo demonstrated that the stimulation procedure for both coated and uncoated electrodes decreased the impedance.