Facile fabrication of biomimetic and conductive hydrogels with robust mechanical properties and 3D printability for wearable strain sensors in wireless human-machine interfaces

In recent decades, advancement towards the Internet of Things (IoT) has underscored the importance of smart materials capable of sensing and responding to real-time environmental feedback, making them pivotal for next-generation flexible electronics. This study presents a novel conductive nanocomposite hydrogel based on oxidized guar gum (OGG) and thiol-functionalized multiwall carbon nanotubes (MWCNTs-SH), synthesized via a “thiol-ene” click reaction incorporating zinc ions as an antibacterial agent, along with hydroxyethyl cellulose and mussel-inspired polydopamine. Our hydrogel overcame limitations related to low hysteresis, conductivity, strong adhesion, self-healing, flexibility, durability, biodegradability, and robust mechanical strength. This was achieved through a dual-crosslinked network that combines chemical and physical cross-linking. Our hydrogel demonstrated remarkable strength (261.3 kPa), recovery efficiency (94 %), high sensitivity (gauge factor of 10.97), and antifatigue performance (100 % strain, 1000 cycles) with rapid response times (120 ms). Its scalable, cost-effective synthesis at room temperature offers a promising method for developing hydrogels tailored to biomedical diagnostics and wearable electronics that are capable of detecting a range of human motions stemming from subtle vibrations to significant joint movements. This methodology paves the way for advanced bio-integrated devices that can enhance human–computer interaction as well as real-time health monitoring systems with unique features.