Hydrogel-Based Sensors: Compositions, Fabrication, Sensing Mechanism, and Applications

Area of Science:

• Materials Science
• Biomedical Engineering
• Environmental Science

Background:

• Hydrogel sensors offer tissue-like properties unmatched by rigid sensors.
• Existing reviews lack an integrated view from material design to sensing performance.

Purpose of the Study:

• To systematically correlate hydrogel polymer chemistry, crosslinking, and fabrication with sensing mechanisms and performance.
• To establish a unified framework for hydrogel-based soft-sensing systems.

Main Methods:

• Critical assessment of natural and synthetic polymers and crosslinking methods.
• Elaboration of multiple sensing modalities (piezoresistive, capacitive, electrochemical, etc.).
• Analysis of emerging platforms and persistent bottlenecks.

Main Results:

• Comprehensive overview of hydrogel sensor design principles and fabrication protocols.
• Detailed analysis of various transduction mechanisms and their performance metrics.
• Identification of challenges like signal drift, stability, selectivity, and manufacturability.

Conclusions:

• A holistic framework is presented, bridging hydrogel molecular design, fabrication, signal transduction, and applications.
• This provides a developmental roadmap for advanced flexible and smart hydrogel sensors.
• Addresses key limitations to guide future research and development.