Physically Cross-Linked Biopolymer-Based Strong and Stretchable Organohydrogel with Self-Healing and Biocompatibility for Environmentally Tolerant Strain Sensors

Clinical Snapshot

Key Findings

• P Value: Not reported

• Effect Size: 85% retention of mechanical properties after self-healing at 40°C

• Primary Outcome: Tensile strain at break of 410.9% with tensile strength of 92.2 kPa for optimised Gel/CDCS1 formulation

• Nnt Or Sensitivity: Gauge factor 1.06-1.34 across strain range; ionic conductivity 0.946 S m⁻¹ at room temperature

• Confidence Interval: Not reported

Clinical Application

Requires clinical validation and regulatory approval before human use; manufacturing scalability needs assessment Would require TGA evaluation as medical device; potential applications align with digital health initiatives and remote patient monitoring programs supported by Medicare Potential applications in patients requiring continuous physiological monitoring, rehabilitation, or wearable medical devices

Abstract

The development of wearable strain sensors increasingly focuses on multifunctional materials that integrate mechanical robustness, self-repairing capacity, temperature-resilient conductivity, and biocompatibility. Herein, we developed a physically cross-linked biopolymer-based organohydrogel by incorporating gelatin (Gel) and β-cyclodextrin-grafted chitosan (CDCS), designated as Gel/CDCS, reinforced through hydrogen bonding, ionic interactions, and host-guest complexation. The optimized Gel/CDCS1 organohydrogel with 1% of CDCS exhibited outstanding stretchability, with a tensile strain at break of 410.9% and a tensile strength of 92.2 kPa, while maintaining 85% of its mechanical properties after self-healing at 40 °C. The introduction of kosmotropic salts (Na3Cit and NaCl) and a glycerol-water binary solvent system conferred remarkable environmental adaptability, allowing stable performance from -20 to 37 °C. Notably, it achieved a high ionic conductivity of 0.946 S m-1 at room temperature, alongside 0.606 S m-1 at -20 °C and 0.330 S m-1 at 37 °C, ensuring operation under extreme conditions. The strain sensor displayed high sensitivity with a gauge factor (GF) increasing from 1.06 to 1.34 over a broad strain range and maintained a stable electrical response over 600 consecutive stretching cycles. Additionally, it enabled reliable detection of diverse human motions, including facial expressions, joint bending, and breathing, demonstrating excellent conformability and signal stability during on-body monitoring. Additionally, Gel/CDCS1 exhibited excellent biodegradability, degrading by over 80% in soil within 4 days, and showed high biocompatibility with fibroblast viability of around 80%. These attributes establish Gel/CDCS1 as a promising eco-friendly candidate for next-generation flexible electronics, wearable strain sensors, and biomedical applications.