Structured adhesives: inspiration, modeling, engineering and applications

Nature has evolved a remarkable diversity of structured adhesives that enable organisms to achieve robust, reversible, and adaptive attachment in natural environments. Unlike conventional chemical glues, these biological adhesives exhibit strong yet controllable adhesion with residue-free detachment, self-cleaning capabilities, and environmental adaptability, which are primarily enabled by their evolutionarily optimized hierarchical architectures. Deciphering the structural and mechanical principles underlying these systems is therefore essential for the rational design of next-generation bioinspired reversible adhesives. This review examines how biological adhesion principles can be translated into engineered structured adhesives by linking biological archetypes, interfacial mechanics, structural design, and functional integration within a unified framework. We discuss the physical mechanisms governing biological adhesion and the theoretical models that have shaped the current understanding of structured adhesive contacts. We then survey fabrication technologies and design strategies to gain enhanced adhesion, detachment regulation, and improved structural adaptability. Furthermore, we highlight emerging design paradigms, including interfacial stress regulation, internally heterogeneous architectures, programmable reversibility, and adhesion-sensing integration, that are shifting structured adhesives from static attachment structures toward adaptive, multifunctional, and intelligent interfaces. Finally, we outline the persistent challenges in structural design, scalable manufacturing, environmental adaptability, and system integration, while offering perspectives on future opportunities for advanced bioinspired adhesives in robotics, wearable systems, and biomedical applications.