Recently electronic tattoo sensors have attracted immense interest for health monitoring mainly due to their higher sensing performance than conventional dry sensors, owing to the ultra-low thickness which results in their conformability to the skin. However, their performance is worse than wet sensors. Further, these electronic tattoo sensors are not durable and reusable when free-standing because of their low thickness and being too delicate. Here, we report a remarkably high-performance freestanding, reusable, ultrathin and ultra-soft electronic tattoo sensor made of parylene-hydrogel double layer system with high water retention over extended periods that can be used for the extended period of 6 months. The hydrogel electronic tattoo (HET) sensors consist of electrically conductive self-adhesive hydrogel with a thickness of 20 µm and Young’s modulus of only 31 kPa at 37 °C, allowing for ultra-conformal contact to the skin microscopic features. Our HET sensors are fabricated using a scalable cost-effective method on ordinary tattoo papers and are laminated on the skin like temporary tattoos and were used for electrophysiological signals recording such as electrocardiography (ECG), electromyography (EMG), and skin hydration, temperature sensing. The HET sensors, for the first time, show 234% lower sensor-skin interface impedance (SSII) and significantly lower susceptibility to motion than gold standard medical grade silver/silver chloride wet gel electrodes which are known to have the lowest SSII and susceptibility to motion. Further, the low HET-skin interface impedance leads to a considerably larger signal amplitude and signal-to-noise ratio (SNR) of the electrophysiological signals recorded using HET sensors in comparison with those obtained using gold standard medical grade silver/silver chloride wet gel electrodes. The SNR of some types of electrophysiological signals such as EMG recorded using HET is up to 19 dB higher than gold standard medical grade electrodes due to higher signal amplitude, significantly lower susceptibility of HET to motion and lower motion artifacts. Also, the HET sensor is the first free-standing ultrathin tattoo sensor that can be transferred from the skin to tattoo paper and vice versa many times and the electrophysiological sensing quality remained high during repeated use for over 6 months.

最近，电子纹身传感器在健康监测领域引起了极大的兴趣，主要是因为它们比传统的干式传感器具有更高的传感性能，而且超薄的厚度导致它们与皮肤的贴合性。然而，它们的性能比湿传感器差。此外，这些电子纹身传感器由于厚度薄且过于脆弱，在独立时不耐用且不可重复使用。在这里，我们报告了一种由聚对二甲苯-水凝胶双层系统制成的高性能独立式、可重复使用、超薄、超柔软的电子纹身传感器，具有高保水性，可长期使用6个月。水凝胶电子纹身 (HET) 传感器由厚度为 20 µm 的导电自粘水凝胶组成，37°C 下杨氏模量仅为 31 kPa，可与皮肤微观特征进行超适形接触。我们的 HET 传感器采用可扩展且经济高效的方法在普通纹身纸上制造，并像临时纹身一样层压在皮肤上，用于电生理信号记录，例如心电图 (ECG)、肌电图 (EMG) 以及皮肤水合、温度传感。与已知具有最低 SSII 和敏感性的金标准医用级银/氯化银湿凝胶电极相比，HET 传感器首次表现出低 234% 的传感器-皮肤界面阻抗 (SSII) 和显着更低的运动敏感性。运动。 此外，与使用金标准医用级银/氯化银湿凝胶获得的信号相比，低 HET-皮肤界面阻抗导致使用 HET 传感器记录的电生理信号的信号幅度和信噪比 (SNR) 要大得多电极。由于信号幅度较高、HET 对运动的敏感性显着降低以及运动伪影较低，某些类型的电生理信号（例如使用 HET 记录的 EMG）的 SNR 比金标准医疗级电极高出 19 dB。此外，HET传感器是第一个独立式超薄纹身传感器，可以多次从皮肤转移到纹身纸，反之亦然，并且在重复使用超过6个月的过程中电生理传感质量仍然保持较高水平。