Pang Qian, Wu Kaihao, Jiang Zilian, Yang Fang, Shi Zewen, Gao Hanlin, Zhang Cuicui, Hou Ruixia, Zhu Yabin
Department of Cell Biology and Regenerative Medicine, Health Science Center, Ningbo University, Ningbo, Zhejiang, 315211, P. R. China.
Biomater Sci. 2023 May 16;11(10):3603-3615. doi: 10.1039/d3bm00074e.
Ionic conductive hydrogels are promising candidates for fabricating wearable sensors for human motion detection and disease diagnosis, and electronic skin. However, most of the existing ionic conductive hydrogel-based sensors primarily respond to a single-strain stimulus. Only a few ionic conductive hydrogels can respond to multiple physiological signals. Although some studies have explored multi-stimulus sensors, such as those detecting strain and temperature, the ability to identify the type of stimulus remains a challenge, which limits their applications. Herein, a multi-responsive nanostructured ionic conductive hydrogel was successfully developed by crosslinking the thermally sensitive poly(-isopropylacrylamide--ionic liquid) conductive nanogel (PNI NG) with a poly(sulfobetaine methacrylate--ionic liquid) (PSI) network. The resultant hydrogel (PNI NG@PSI) was endowed with good mechanical stretchability (300%), resilience and fatigue resistance, and excellent conductivity (2.4 S m). Furthermore, the hydrogel exhibited a sensitive and stable electrical signal response and has a potential application in human motion detection. Moreover, the introduction of a nanostructured thermally responsive PNIPAAm network also endowed it with a sensitive and unique thermal-sensing ability to timely and accurately record temperature changes in the range of 30-45 °C, holding promise for application as a wearable temperature sensor to detect fever or inflammation in the human body. In particular, as a dual strain-temperature sensor, the hydrogel demonstrated an excellent capability of distinguishing the type of stimulus from superposed strain-temperature stimuli electrical signals. Therefore, the implementation of the proposed hydrogel in wearable multi-signal sensors provides a new strategy for different applications, such as health monitoring and human-machine interactions.
离子导电水凝胶是用于制造用于人体运动检测、疾病诊断的可穿戴传感器以及电子皮肤的有前途的候选材料。然而，现有的大多数基于离子导电水凝胶的传感器主要对单一应变刺激做出响应。只有少数离子导电水凝胶能够对多种生理信号做出响应。尽管一些研究已经探索了多刺激传感器，例如检测应变和温度的传感器，但识别刺激类型的能力仍然是一个挑战，这限制了它们的应用。在此，通过将热敏聚（N-异丙基丙烯酰胺-离子液体）导电纳米凝胶（PNI NG）与聚（甲基丙烯酸磺酸甜菜碱-离子液体）（PSI）网络交联，成功开发了一种多响应纳米结构离子导电水凝胶。所得水凝胶（PNI NG@PSI）具有良好的机械拉伸性（300%）、弹性和抗疲劳性，以及优异的导电性（2.4 S m）。此外，该水凝胶表现出灵敏且稳定的电信号响应，在人体运动检测中具有潜在应用。此外，纳米结构热敏聚N-异丙基丙烯酰胺网络的引入还赋予了它灵敏且独特的热传感能力，能够及时准确地记录30-45°C范围内的温度变化，有望作为可穿戴温度传感器用于检测人体发烧或炎症。特别是，作为一种双应变-温度传感器，该水凝胶在区分叠加应变-温度刺激产生的电信号的刺激类型方面表现出优异的能力。因此，所提出的水凝胶在可穿戴多信号传感器中的应用为健康监测和人机交互等不同应用提供了一种新策略。
