Engineering versatile chitosan hydrogel sensor for satisfying complex and harsh demands.

Area of Science:

• Materials Science
• Biomedical Engineering
• Polymer Chemistry

Background:

• Chitosan-based hydrogels are promising for sensors but face challenges in mechanical robustness, environmental stability (anti-freezing/drying), and biocompatibility.
• Existing hydrogel sensors often compromise performance under extreme temperature or prolonged dry conditions.

Purpose of the Study:

• To develop a chitosan-based hydrogel sensor with enhanced mechanical properties, simultaneous anti-freezing and anti-drying capabilities, and excellent biocompatibility.
• To overcome the limitations of current hydrogel sensors for real-world applications in diverse environments.

Main Methods:

• Fabrication of a novel chitosan-based hydrogel sensor (CS/PVA/GL) using a superhydrogen-bond networks (SHBNs) strategy.
• Characterization of mechanical performance (load capacity up to 60 kg), cell viability (99%), anti-freezing properties (glass transition temperature of -100 °C), and stability under extreme temperatures (-75 °C) and prolonged dryness (60 days).

Main Results:

• The CS/PVA/GL hydrogel exhibited excellent mechanical properties and 99% cell viability.
• The hydrogel demonstrated exceptional anti-freezing capacity with a glass transition temperature of -100 °C and maintained flexibility and conductivity after freezing at -75 °C.
• The hydrogel showed remarkable anti-drying capacity, retaining flexibility and even improved mechanical properties after 60 days of dryness, with anti-freezing capacity close to pre-drying levels.

Conclusions:

• The SHBNs strategy effectively creates a high-performance chitosan-based hydrogel sensor with superior mechanical strength, and exceptional resistance to freezing and drying.
• The developed hydrogel sensor can monitor human motion and function as bionic skin, highlighting its potential for real-time applications in extreme environments.
• This engineering approach offers valuable insights for designing advanced hydrogel sensors for demanding applications.