Kearwan Natchapat, Promphet Nadtinan, Rodthongkum Nadnudda, Hoven Voravee P, Narupai Benjaporn
Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
Center of Excellence in Responsive Wearable Materials, Chulalongkorn University, Bangkok 10330, Thailand.
ACS Appl Mater Interfaces. 2025 Sep 17;17(37):52580-52593. doi: 10.1021/acsami.5c10251. Epub 2025 Sep 8.
Strain sensors have received considerable attention in personal healthcare due to their ability to monitor real-time human movement. However, the lack of chemical sensing capabilities in existing strain sensors limits their utility for continuous biometric monitoring. Although the development of dual wearable sensors capable of simultaneously monitoring human motion and biometric data presents significant challenges, the ability to fabricate these sensors with geometries tailored to individual users is highly desirable. Herein, we report three-dimensional (3D)-printed flexible conductive hydrogels designed to serve dual functions as both strain and colorimetric sensors for sweat lactate detection. Poly(ethylene glycol)-bisurethane methacrylate with varying molecular weights was synthesized and utilized as a cross-linker in photopolymerizable resins. These resins were employed to fabricate various 3D complex architectures via a liquid crystal display 3D printer, resulting in hydrogels with remarkable mechanical properties, including excellent stretchability, toughness, elastic recovery, and fatigue resistance. Postfabrication treatment with NaOH enhances the ionic conductivity of the hydrogel, enabling its use as a strain sensor capable of detecting compression, bending, and stretching through real-time resistance changes. In addition, a lactate assay was immobilized onto the hydrogel, allowing it to function as a colorimetric sensor for sweat lactate with a detection range of 0 to 25 mM, encompassing the physiological threshold associated with muscle fatigue. These dual-function sensors facilitate comprehensive, real-time monitoring of both human physiological activities and lactate levels within a single device, highlighting their potential for the on-demand fabrication of customizable smart health-monitoring systems.
应变传感器因其能够监测人体实时运动而在个人医疗保健领域受到了广泛关注。然而，现有应变传感器缺乏化学传感能力，限制了它们在连续生物特征监测中的应用。尽管开发能够同时监测人体运动和生物特征数据的双功能可穿戴传感器面临重大挑战，但能够制造出适合个体用户几何形状的这些传感器是非常理想的。在此，我们报道了一种三维（3D）打印的柔性导电水凝胶，它被设计用于同时作为应变传感器和比色传感器来检测汗液中的乳酸。合成了具有不同分子量的聚（乙二醇）-双异氰酸酯甲基丙烯酸酯，并将其用作可光聚合树脂中的交联剂。通过液晶显示器3D打印机使用这些树脂制造各种3D复杂结构，从而得到具有卓越机械性能的水凝胶，包括出色的拉伸性、韧性、弹性恢复和抗疲劳性。用氢氧化钠进行后处理可提高水凝胶的离子导电性，使其能够用作应变传感器，通过实时电阻变化检测压缩、弯曲和拉伸。此外，将乳酸测定法固定在水凝胶上，使其能够作为汗液乳酸的比色传感器，检测范围为0至25 mM，涵盖与肌肉疲劳相关的生理阈值。这些双功能传感器便于在单个设备中对人体生理活动和乳酸水平进行全面、实时监测，突出了它们在按需制造可定制智能健康监测系统方面的潜力。
