Flexible Sensors Based on Deep Eutectic Solvent Gels: Preparation Methods, Material Design, and Research Progress

Flexible sensors have attracted considerable attention as core components for precise human physiological monitoring, demonstrating promising prospects in biomedical engineering, wearable devices, and soft robotics. Conventional sensors are fundamentally limited by their materials. Deep Eutectic Solvent（DES）gel-based sensors benefit from eco-compatibility, tunable conduction mechanisms, and thermal resilience, significantly advancing flexible sensing platforms. This review systematically summarizes recent advances in DES gel-based flexible sensors, including mechanisms, fabrication strategies, materials, structural designs, and applications. It also discusses performance improvement strategies and identifies future opportunities and challenges, aiming to promote wider adoption and innovation of DES gels in flexible sensing technologies. • Proposes a framework for entire DES gel sensor development, bridging disciplines. • Comprehensive analysis of DES gel compatibility across four sensing mechanisms. • Classes fabrication; cites smart, green, integrated processing as future trends. • Examines material design: crosslinking, fillers, dynamic bonds tune properties. • Assesses real-world uses and industrial potential, noting key challenges.