仿“壁虎脚”柔性表面生物电干电极的构建及动态噪声机理研究

Angiocardiopathy is a worldwide severe problem, and wearable health monitoring system (WHMS) is one of effective ways for decreasing the mortalilty of chronic angiocardiopathy patients. However, motion artifact between surface biopotential dry electrode and skin restricts the popularization of WHMS. In this project, poly(glycerol sebacate acrylate)(PGSA) solution was poured into double-layers porous anodization alumina (PAA) to construct gecko-foot-mimetic substrate by spin coating method, titanium or gold was coating on surface of substrate by magnetron sputtering or vacuum deposition method to acquire gecko-foot-mimetic flexible surface biopotential dry electrode (GFM-FSBDE), and correlation models between surface structure of GFM-FSBDE and adhesion force will be systematically investigated. Subsequently, impedance spectra and dynamic open circuit potential variation (motion artifact) of GFM-FSBDE/electrolyte/membrane interface will be measured by using dynamic measurement system which was developed in our lab.Equivalent circuits of GFM-FSBDE /membrane interface will be constructed, quantitative model between motion artifact and parameters such as relative motion speed, relative displacement,pressure fluctuation, and humidity variation of GFM-FSBDE /membrane interface will be acquired, furthermore, the mechanism of motion artifact of GFM-FSBDE /membrane interface will be also illuminated, above described achievements will provide experimental and theoretical supports for developing low motion artifact GFM-FSBDE and WHMS.

心血管病是世界各国面临的严重问题，可穿健康监控系统是降低患者死亡率的有效途径之一。然而，表面生物电干电极与皮肤间存在的动态噪声制约了可穿健康监控系统的应用推广。本项目拟将聚（癸二酸丙三醇酯）（PGSA）溶液以旋涂法浇注到双层多孔阳极氧化铝膜中构建出仿"壁虎脚"基底，采用磁控溅射或真空镀方法在基底上镀钛或金开发出仿"壁虎脚"表面生物电干电极，并系统地研究电极表面结构与粘附力之间的函数关系。基于自主开发的动态测量系统测量仿"壁虎脚"表面生物电干电极/电解质/模拟皮肤间的阻抗谱和动态开路电压变化量（即动态噪声），建立电极/皮肤界面等效电路，分析动态噪声与电极/皮肤间相对运动速度、相对位移、压力波动幅度和湿度变化量等之间关系，建立各参数与动态噪声间的定量模型，进而阐明仿壁虎脚表面电极/电解质界面的动态噪声机理，为开发低动态噪声表面生物电电极和可穿健康监控系统提供实验和理论支持。

用于生物电长期监测的智能服装服饰存在动态噪声和皮肤/电极界面舒适性低的缺点是制约其应用推广的主要瓶颈。本课题采用阳极氧化法制备了单层和双层多孔阳极氧化铝（PAA）模板，首先利用模板旋涂法制备了仿壁虎脚高聚物材料，随后通过原位还原法和化学镀法在仿壁虎脚材料表面镀上银层，聚多巴胺作为偶联剂能有效提高了银层稳定性，此外，通过一步原位聚合法可以制备出纳米阵列聚吡咯导电膜，将导电薄膜与织物基底集成制备出柔性生物电干电极，应用自主研发的生物电干电极动态性能评价系统（DPES）测试开发电极的各项性能指标。课题组提出了利用磷酸和草酸混合溶液为电解液制备出了孔间距在300-500nm范围内可连续调节的PAA模板的新方法。并且通过变换电解质和调整阳极氧化电压，可以制备双层和锥形PAA模板，双层PAA膜的小孔层孔间距和氧化电压存在线性增长关系，PAA模板的生长速度随氧化电压的增大呈指数增长；模板-旋涂法制备的聚甲基丙烯酸甲酯(PMMA)纳米阵列膜的表面接触角为116度，超出表面平滑PMMA膜48度。通过原位聚合反应在PAA模板内获得了规整纳米阵列导电薄膜，采用了盐酸作为掺杂剂改善了聚吡咯薄膜的导电性。电化学沉积法在PAA模板内生成银纳米棒的最优电压是13-15V，银纳米棒的直径可以通过PAA模板的孔径调控，其长度在沉积25分钟后基本保持在3.5um左右。当硝酸银浓度为140g/L,多巴胺浓度为4 g/L时，织物和纳米阵列膜表面银镀层的电阻率大约是0.1 Ω.cm。DPES能够获得生物电干电极的阻抗谱、动静态开路电压、生物电信号的衰减幅度和信号失真度等参数，避免了人体评价生物电干电极性能带来的不确定性和精度差的缺点，应用同样的织物电极在该系统进行多次阻抗谱测量，结果显示电极的阻抗和相位角的最大变异系数分别小于5.1%和7.6%，DPES具有较好的重复性。利用织物电极和纳米阵列结构电极开发了心电监测腰带和服装，测试结果显示织物电极的最优尺寸是25mm直径。表面微纳米结构的生物电干电极能够有效提高电极与皮肤表面的接触并改善电极的性能。