Hydrogel Adhesive with Tunable Multifunctionality by the Addition of Weak Bonds Based on Polydopamine for Versatile Wound Healing Applications and Biointerfaces

Developing high-performance adhesives that integrate both strength and flexibility is essential for versatile medical applications; however, achieving both properties simultaneously in a single material remains a challenge. In this study, we introduce polydopamine (PDA) into hydrogel networks to form sacrificial bonds, which consist of multiple types of noncovalent, energy-dissipating interactions under stress, allowing the material to stretch and recover without breaking. This mechanism not only enables synergistic interactions that enhance both strength and extensibility but also allows for rapid and robust adhesion to various tissue interfaces, effectively sealing defects and stopping bleeding in models of tail, liver, and heart injuries. Additionally, the hydrogels demonstrate excellent antibacterial properties, biocompatibility, and <i>in situ</i> macrophage modulation. In both rat and pig injury models, the hydrogel adhesives efficiently close wounds and accelerate healing. These findings underscore the significant potential of these sacrificially bonded hydrogels for surgical applications, including hemostatic sealing, infection prevention, and sutureless wound closure. Additionally, they could also serve as bioelectronics interfacing materials, enabling the recording and stimulation of physiological activities.