Mechanically resilient, freeze-resistant, and antibacterial carboxymethyl cellulose/phytic acid hydrogel sensors for respiratory monitoring

Hydrogels are promising materials for flexible wearable electronics; however, they often encounter limitations in practical applications due to environmental instability and weak mechanical properties. This study developed a multifunctional composite hydrogel by integrating phytic acid (PA) and hydrophobic lauryl methacrylate (LMA) chains into a polyacrylamide (PAM) and carboxymethyl cellulose (CMC) network, resulting in a synergistic multi-dynamic cross-linked structure. The hydrogel exhibits remarkable tensile strength (1.06 MPa), high ionic conductivity (1.45 S/m), and excellent environmental tolerance, maintaining its flexibility and conductivity even at −20 °C. Additionally, it demonstrates significant anti-swelling properties, broad-spectrum antimicrobial activity, and outstanding cytocompatibility (cell viability >97 %). As a multifunctional sensor, it shows high sensitivity (GF = 2.13), a fast response time, and stable performance over more than 1000 cycles. This hydrogel sensor reliably monitors physiological signals such as electrocardiograms (ECG), electromyograms (EMG), and respiratory patterns, demonstrating particular promise in diagnosing sleep-related breathing abnormalities in patients with heart failure. This study provides a robust and versatile platform for next-generation wearable devices.