Li Linze, Jiang Changqing, Li Luming
School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350108, China.
National Engineering Research Center of Neuromodulation, School of Aerospace Engineering, Tsinghua University, Beijing 100084, China.
Micromachines (Basel). 2023 Dec 29;15(1):70. doi: 10.3390/mi15010070.
Implantable electrodes are crucial for stimulation safety and recording quality of neuronal activity. To enhance their electrochemical performance, electrodeposited nanostructured platinum (nanoPt) and iridium oxide (IrO) have been proposed due to their advantages of in situ deposition and ease of processing. However, their unstable adhesion has been a challenge in practical applications. This study investigated the electrochemical performance and stability of nanoPt and IrO coatings on hierarchical platinum-iridium (Pt-Ir) substrates prepared by femtosecond laser, compared with the coatings on smooth Pt-Ir substrates. Ultrasonic testing, agarose gel testing, and cyclic voltammetry (CV) testing were used to evaluate the coatings' stability. Results showed that the hierarchical Pt-Ir substrate significantly enhanced the charge-storage capacity of electrodes with both coatings to more than 330 mC/cm, which was over 75 times that of the smooth Pt-Ir electrode. The hierarchical substrate could also reduce the cracking of nanoPt coatings after ultrasonic, agarose gel and CV testing. Although some shedding was observed in the IrO coating on the hierarchical substrate after one hour of sonication, it showed good stability in the agarose gel and CV tests. Stable nanoPt and IrO coatings may not only improve the electrochemical performance but also benefit the function of neurobiochemical detection.
可植入电极对于神经元活动的刺激安全性和记录质量至关重要。为了提高其电化学性能，人们提出了电沉积纳米结构铂（nanoPt）和氧化铱（IrO），因为它们具有原位沉积和易于加工的优点。然而，它们不稳定的附着力在实际应用中一直是一个挑战。本研究调查了飞秒激光制备的分级铂铱（Pt-Ir）基底上nanoPt和IrO涂层的电化学性能和稳定性，并与光滑Pt-Ir基底上的涂层进行了比较。采用超声测试、琼脂糖凝胶测试和循环伏安法（CV）测试来评估涂层的稳定性。结果表明，分级Pt-Ir基底显著提高了两种涂层电极的电荷存储容量，使其超过330 mC/cm，这是光滑Pt-Ir电极的75倍以上。分级基底还可以减少超声、琼脂糖凝胶和CV测试后nanoPt涂层的开裂。虽然在超声处理1小时后，分级基底上的IrO涂层出现了一些脱落，但它在琼脂糖凝胶和CV测试中表现出良好的稳定性。稳定的nanoPt和IrO涂层不仅可以改善电化学性能，还可能有利于神经生化检测功能。
