Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA.
Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA.
Sensors (Basel). 2022 Nov 4;22(21):8510. doi: 10.3390/s22218510.
Dry electrodes offer an accessible continuous acquisition of biopotential signals as part of current in-home monitoring systems but often face challenges of high-contact impedance that results in poor signal quality. The performance of dry electrodes could be affected by electrode material and skin hydration. Herein, we investigate these dependencies using a circuit skin-electrode interface model, varying material and hydration in controlled benchtop experiments on a biomimetic skin phantom simulating dry and hydrated skin. Results of the model demonstrate the contribution of the individual components in the circuit to total impedance and assist in understanding the role of electrode material in the mechanistic principle of dry electrodes. Validation was performed by conducting in vivo skin-electrode contact impedance measurements across ten normative human subjects. Further, the impact of the electrode on biopotential signal quality was evaluated by demonstrating an ability to capture clinically relevant electrocardiogram signals by using dry electrodes integrated into a toilet seat cardiovascular monitoring system. Titanium electrodes resulted in better signal quality than stainless steel electrodes. Results suggest that relative permittivity of native oxide of electrode material come into contact with the skin contributes to the interface impedance, and can lead to enhancement in the capacitive coupling of biopotential signals, especially in dry skin individuals.
干电极可作为当前家庭监测系统的一部分，实现生物电位信号的连续可及采集，但通常面临高接触阻抗的挑战，导致信号质量较差。干电极的性能可能受到电极材料和皮肤水合作用的影响。本文通过电路皮肤-电极接口模型进行了这些相关性的研究，在模拟干和湿皮肤的仿生皮肤仿体上进行了受控台式实验，改变了材料和水合作用。模型结果表明了电路中各个组件对总阻抗的贡献，并有助于理解电极材料在干电极机械原理中的作用。通过对十个正常人体进行的体内皮肤-电极接触阻抗测量进行了验证。此外，通过展示将干电极集成到马桶座心血管监测系统中以捕获临床相关心电图信号的能力，评估了电极对生物电位信号质量的影响。钛电极产生的信号质量优于不锈钢电极。结果表明，与皮肤接触的电极材料的本征氧化物的相对介电常数有助于界面阻抗，并能增强生物电位信号的电容耦合，尤其是在干燥皮肤个体中。
