Failure mechanisms of hydrogel-wet tissue adhesive interfaces: an energy dissipation perspective

Abstract Hydrogel-wet tissue adhesive systems hold great promise for biomedicine and bioelectronics, yet their practical application is severely restricted by interfacial failure in complex physiological environments. Such adhesives frequently suffer from fatigue, delamination and slippage well before reaching their theoretical adhesive strength, proving that conventional strength-based evaluation cannot reflect their actual stability. Classical fracture mechanics and viscoelastic adhesion theories describe failure through energy release rate, work of adhesion, and rate-dependent fracture energy, but they commonly incorporate dissipation into an effective fracture parameter and do not explicitly resolve how energy is stored at the interface, transferred into the bulk, and dissipated across the hydrated interface−bulk continuum. This review organizes current hydrogel-tissue adhesion strategies into a three-tier energy-regulation framework comprising interfacial buffering, interface-to-bulk energy transfer, and bulk dissipation. The framework is connected to measurable quantities, including energy release rate, effective fracture energy, fatigue threshold, interfacial stress concentration, transfer efficiency, and hysteresis loss, to provide semi-quantitative guidance for material design and comparison. Key failure modes, representative structural and molecular strategies, and a practical characterization workflow are discussed. Remaining challenges in parameter identification, cross-scale constitutive modeling, and in vivo validation are outlined.