Carvalho Daniel, Rodrigues Ana Margarida, Santos João, Geraldo Dulce, Ferreira Armando, Correa Marcio Assolin, Alves Eduardo, Barradas Nuno Pessoa, Lopes Claudia, Vaz Filipe
Physics Centre of Minho and Porto Universities (CF-UM-UP), University of Minho, 4710-057 Braga, Portugal.
Chemistry Centre, University of Minho, 4710-057 Braga, Portugal.
Sensors (Basel). 2024 Nov 23;24(23):7477. doi: 10.3390/s24237477.
This study aimed to investigate the degradation of dry biopotential electrodes using the anodic stripping voltammetry (ASV) technique. The electrodes were based on Ti-Cu thin films deposited on different polymeric substrates (polyurethane, polylactic acid, and cellulose) by Direct Current (DC) magnetron sputtering. TiCu thin films (chemical composition of 25.4 at.% Cu and 74.6 at.% Ti) were prepared by sputtering a composite Ti target. For comparison purposes, a Cu-pure thin film was prepared under the same conditions and used as a reference. Both films exhibited dense microstructures with differences in surface topography and crystalline structure. The degradation process involved immersing TiCu and Cu-pure thin films in artificial sweat (prepared following the ISO standard 3160-2) for different durations (1 h, 4 h, 24 h, 168 h, and 240 h). ASV was the technique selected to quantify the amount of Cu(II) released by the electrodes immersed in the sweat solution. The optimal analysis conditions were set for 120 s and -1.0 V for time deposition and potential deposition, respectively, with a quantification limit of 0.050 ppm and a detection limit of 0.016 ppm. The results showed that TiCu electrodes on polyurethane substrates were significantly more reliable over time compared to Cu-pure electrodes. After 240 h of immersion, the TiCu electrodes released a maximum of 0.06 ppm Cu, while Cu-pure electrodes released 16 ppm. The results showed the significant impact of the substrate on the electrode's longevity, with cellulose bases performing poorly. TiCu thin films on cellulose released 1.15 µg/cm of copper after 240 h, compared to 1.12 mg/cm from Cu-pure films deposited on the same substrate. Optical microscopy revealed that electrodes based on polylactic acid substrates were more prone to corrosion over time, whereas TiCu thin-film metallic glass-like structures on PU substrates showed extended lifespan. This study underscored the importance of assessing the degradation of dry biopotential electrodes for e-health applications, contributing to developing more durable and reliable sensing devices. While the study simulated real-world conditions using artificial sweat, it did not involve in vivo measurements.
本研究旨在利用阳极溶出伏安法（ASV）技术研究干式生物电位电极的降解情况。这些电极基于通过直流（DC）磁控溅射沉积在不同聚合物基底（聚氨酯、聚乳酸和纤维素）上的Ti-Cu薄膜。通过溅射复合Ti靶制备了TiCu薄膜（化学组成为25.4原子%的Cu和74.6原子%的Ti）。为了进行比较，在相同条件下制备了纯Cu薄膜并用作参考。两种薄膜均呈现出致密的微观结构，但在表面形貌和晶体结构上存在差异。降解过程包括将TiCu和纯Cu薄膜在人工汗液（按照ISO标准3160-2制备）中浸泡不同时间（1小时、4小时、24小时、168小时和240小时）。ASV是用于量化浸泡在汗液溶液中的电极释放的Cu(II)量的技术。分别将时间沉积和电位沉积的最佳分析条件设置为120秒和-1.0伏，定量限为0.050 ppm，检测限为0.016 ppm。结果表明，与纯Cu电极相比，聚氨酯基底上的TiCu电极随时间推移明显更可靠。浸泡240小时后，TiCu电极最多释放0.06 ppm的Cu，而纯Cu电极释放16 ppm。结果表明基底对电极寿命有显著影响，纤维素基底的性能较差。纤维素上的TiCu薄膜在240小时后释放1.15 μg/cm的铜，而沉积在相同基底上的纯Cu薄膜释放1.12 mg/cm。光学显微镜显示，基于聚乳酸基底的电极随时间推移更容易腐蚀，而聚氨酯基底上的TiCu薄膜类金属玻璃结构显示出更长的寿命。本研究强调了评估用于电子健康应用的干式生物电位电极降解情况的重要性，有助于开发更耐用、更可靠的传感设备。虽然该研究使用人工汗液模拟了实际情况，但未涉及体内测量。
