Dual-crosslinked liquid metal-cellulose hydrogels with synergistic conduction networks for multimodal wearable biosensing.

The exponential growth of smart electronics has intensified demand for next-generation wearable sensors, yet achieving optimal flexibility, durability, and biocompatibility remains challenging. This study introduces a dual-network hydrogel (CMC-PAM-LM) developed through the synergistic integration of carboxymethyl cellulose sodium (CMC), polyacrylamide (PAM), and liquid metal (LM). The hydrogel incorporates two distinct crosslinking mechanisms: dynamic coordination between Ga ions from LM and carboxylate groups on CMC chains, and covalent crosslinking between the CMC and PAM networks. This dual-crosslinking strategy endows the material with exceptional mechanical resilience (fracture stress: 114.81 kPa, strain: 778.24 %), superior electrical conductivity (0.63 S/m), and self-healing capability. Furthermore, the hydrogel demonstrates remarkable fatigue resistance (>800 cycles), rapid strain response (∼30 ms), and universal adhesion to diverse substrates. Its efficacy as a multimodal sensor is validated through real-time human motion tracking, electrochemical sweat analysis, and secure information transmission. These results establish a promising material paradigm for high-performance, flexible electronics, providing valuable insights for future wearable technology development.