Mechanical Metamaterials for Bioengineering: In Vitro, Wearable, and Implantable Applications

Mechanical metamaterials represent a promising class of materials characterized by unconventional mechanical properties derived from their engineered architectures. In the realm of bioengineering, these materials offer unique opportunities for applications spanning in vitro models, wearable devices, and implantable biomedical technologies. This review discusses recent advancements and applications of mechanical metamaterials in bioengineering contexts. Mechanical metamaterials, tailored to mimic specific mechanical properties of biological tissues, enhance the fidelity and relevance of in vitro models for disease modeling and therapy testing. Integration of these materials into wearable devices enables the creation of comfortable and adaptive interfaces with the human body. Utilization of mechanical metamaterials in implantable devices promotes tissue regeneration, supports biomechanical functions, and minimizes host immune responses. Key design strategies and material selection criteria critical for optimizing the performance and biocompatibility of these metamaterials are elucidated. Representative case studies demonstrating recent applications in benchtop phantoms and scaffolds (in vitro platforms); footwear, architectured fabrics, and epidermal sensors (wearables); and implantable cardiovascular, gastrointestinal, and orthopedic devices, and multifunctional patches are highlighted. Finally, the challenges and future directions in the field are discussed, emphasizing the potential for mechanical metamaterials to transform bioengineering research by enabling novel functionalities and improving outcomes across diverse use cases.