Mascia Antonello, Collu Riccardo, Makni Nasreddine, Concas Mattia, Barbaro Massimo, Cosseddu Piero
Department of Electrical and Electronics Engineering, University of Cagliari, Piazza D'Armi, 09123 Cagliari, Italy.
Sensors (Basel). 2025 Jul 23;25(15):4568. doi: 10.3390/s25154568.
This study presents a comprehensive evaluation and an equivalent circuit modeling of the skin-electrode impedance characteristics of three types of ultra-thin tattoo electrodes, all based on Parylene C nanofilms but with different active materials: Gold, Silver, and PEDOT:PSS. Their performance was compared to standard disposable Ag/AgCl electrodes. Impedance measurements were carried out on six human subjects under controlled conditions, assessing the frequency response in the range of 20 Hz to 1 kHz. For each subject, the impedance was recorded six times over one hour to investigate the stability and the temporal performance. The collected data were subsequently analyzed to model the electrical properties and interface behavior of each electrode type. The findings demonstrate that the tattoo electrodes offer impedance levels comparable to those of Ag/AgCl electrodes (in the order of tens of kΩ at 20 Hz), while providing additional benefits such as enhanced conformability, improved skin adhesion, and reduced skin irritation during use. Furthermore, the modeling of the skin-electrode interface through a more detailed equivalent circuit than the single time constant model enables a more detailed interface analysis and description, with fitting algorithm R scores of about 0.999 and 0.979 for the impedance magnitude and impedance phase, respectively. The proposed equivalent circuit offers valuable insights for optimizing electrode design, supporting the potential of Parylene C-based tattoo electrodes as promising alternatives for next-generation wearable bioelectronic applications.
本研究对三种基于聚对二甲苯C纳米薄膜但活性材料不同（金、银和聚3,4-乙撑二氧噻吩：聚苯乙烯磺酸盐）的超薄纹身电极的皮肤-电极阻抗特性进行了全面评估和等效电路建模。将它们的性能与标准一次性Ag/AgCl电极进行了比较。在受控条件下对六名人类受试者进行了阻抗测量，评估了20 Hz至1 kHz范围内的频率响应。对于每个受试者，在一小时内记录六次阻抗，以研究稳定性和时间性能。随后对收集到的数据进行分析，以模拟每种电极类型的电学性质和界面行为。研究结果表明，纹身电极的阻抗水平与Ag/AgCl电极相当（在20 Hz时为几十千欧），同时还具有其他优点，如增强的贴合性、改善的皮肤粘附性以及使用过程中减少皮肤刺激。此外，通过比单时间常数模型更详细的等效电路对皮肤-电极界面进行建模，可以进行更详细的界面分析和描述，阻抗幅值和阻抗相位的拟合算法R分数分别约为0.999和0.979。所提出的等效电路为优化电极设计提供了有价值的见解，支持了基于聚对二甲苯C的纹身电极作为下一代可穿戴生物电子应用有前景的替代方案的潜力。
