用于生理电信号测量的金属微针阵列电极制备及其性能研究

Fabrication of Metal Microneedle Array Electrode for Bio-signals Monitoring

生理电信号是疾病诊断与治疗的重要指标,在临床上具有重要意义。医用微针阵列电极是测量人体生理电信号的重要传感元件,但因工艺复杂,易脆断,稳定性差等问题,至今无法商用。设计并制造了一种金属微针阵列电极,可对人体心电、肌电、脑电等生理电信号进行直接、高效测量。采用慢走丝线切割方法制备316L不锈钢四棱锥微针阵列电极。微针阵列电极10×10排布,微针高度930μm,底部宽度400μm,针尖半径10μm,微针加工精度高。力学试验表明,微针阵列电极多次穿刺无弯折或者断裂,具有良好的力学性能。微针阵列穿刺皮肤角质层,在皮肤表面形成微孔阵列通道。通过经皮水分流失测试发现,穿刺皮肤可在40 min后恢复,无炎症与感染现象。微针阵列电极检测的心电信号在波形,频率,峰值方面与标准电极非常相似;肌电信号可准确反映肌肉运动状态,较标准电极具有更高的幅值;微针阵列电极可准确完整记录人体睁闭眼,眨眼动作过程中脑电信号。微针阵列电极具有良好的生理电信号测量性能,且微针阵列电极无需皮肤准备,直接贴敷检测,适合长期监测,有望部分替代传统商用电极。

Human bio-signals are important indicators for disease diagnosis and clinical treatment. The medical microneedle array electrode(MAE) is an important sensor to measure bio-signals of human body. However, MAE has not been clinical application due to its complex fabrication process and poor mechanical strength. In this work, a metal MAE is one-step fabricated by low speed wire electrical discharge machine(LSWEDM) for bio-signals monitoring, including ECG, EMG and EEG. 316 L stainless steel is cut and fabricated into the pyramid MAE by LSWEDM. MAE consisted of a 10×10 microneedles array with a height of 930 μm, bottom width of 400 μm and tip radius of 10 μm. MAE had good mechanical strength without bending or broken under repeated insertions. MAE could easily penetrate through the stratum corneum of skin and formed microchannels in the skin. Transepidermal water loss(TEWL) test demonstrated that skin could be recovered in 40 min after skin penetration by MAE. ECG signals recorded by MAE exhibited very similar waveform with standard Ag/AgCl electrode. EMG signals collected by MAE could reflect the motion of the muscle with higher amplitude. MAE could accurately and completely record the EEG signals under eye opening-closing and blinking. MAE could directly detect the bio-signals without skin preparation, exhibited good potential for bio-signals monitoring and suitable for long-term monitoring.