Department of Mechanical & Electrical Engineering, Xiamen University, Xiamen, 361102, China.
School of Engineering, Sun Yat-Sen University, Guangzhou, 510006, China.
Biomed Microdevices. 2019 Jul 22;21(3):74. doi: 10.1007/s10544-019-0422-9.
Magnetic field assisted laser fabrication is proposed to process metal dry bioelectrode with surface microstructures. The effects of magnetic flux density on the geometrical dimension of surface microstructures of bioelectrode is investigated. The electrode-skin contact impedance is then studied using the two-electrode measurement method. Finally, electromyography (EMG) signal is recorded using bioelectrodes processed in different magnetic flux density. Our results show that the magnetic field has obvious influences on the height and bottom width of microstructure of bioelectrode. When a magnetic field of 100 mT is selected, larger height-width ratio of microstructures is obtained, which provides a stronger ability to penetrate stratum corneum. Consequently, much lower contact impedance is obtained. Signal-noise ratio (SNR) of EMG signal shows a correlation coefficient of 0.9836 with height-width ratio of microstructures on the surface of metal dry bioelectrodes. Raw EMG signals recorded by metal dry bioelectrodes in 100 mT magnetic field show a high SNR up to 27.350, which is slightly higher than that of traditional Ag/AgCl wet bioelectrodes (26.689). By stationary wavelet transform (SWT) de-noising, noise interfused in raw EMG signals is suppressed effectively. Moreover, the de-noised EMG signal recorded using metal dry bioelectrodes processed in 100 mT magnetic field still remains a fairly high SNR.
磁场辅助激光加工被提出用于加工具有表面微结构的金属干式生物电极。研究了磁场通量密度对生物电极表面微结构几何尺寸的影响。然后使用双电极测量方法研究了电极-皮肤接触阻抗。最后，使用在不同磁场通量密度下加工的生物电极记录肌电图（EMG）信号。我们的结果表明，磁场对生物电极微结构的高度和底部宽度有明显的影响。当选择 100 mT 的磁场时，获得了更大的微结构高度-宽度比，这提供了更强的穿透角质层的能力。因此，获得了更低的接触阻抗。表面具有微结构的金属干式生物电极的 EMG 信号的信噪比（SNR）与微结构的高度-宽度比呈 0.9836 的相关系数。在 100 mT 磁场中记录的金属干式生物电极的原始 EMG 信号具有高达 27.350 的高 SNR，略高于传统的 Ag/AgCl 湿生物电极（26.689）。通过驻波变换（SWT）去噪，有效地抑制了原始 EMG 信号中混入的噪声。此外，使用在 100 mT 磁场下加工的金属干式生物电极记录的去噪 EMG 信号仍然保持相当高的 SNR。
