Melt electrowriting for bone repair: A review of scaffold architectures and material selection

Bone regeneration presents a significant engineering challenge, necessitating the development of advanced scaffold fabrication techniques to provide mechanical support, guide cellular activity, and promote tissue integration. The design and fabrication of scaffolds play a crucial role in enhancing bone repair by offering tailored structural properties, controlled degradation rates, and optimized porosity for cell migration and vascularization. Various manufacturing methods, from traditional machining and molding to emergent additive manufacturing (AM) approaches, have been explored to create scaffolds with optimized mechanical properties and bioactivity. Among these, melt electrowriting (MEW) has emerged as a high-precision AM technique, offering unprecedented control over scaffold architecture at the microscale. Specifically, MEW enables the fabrication of scaffolds with fine-tuned fiber alignment, pore geometry, and hierarchical structures, making it a promising approach for engineering bone tissues. This review is the first to concurrently examine both architectural design and material selection in MEW-based bone scaffolds. We synthesize recent advancements in MEW-enabled scaffold architectures and biomaterials, emphasizing design strategies and material considerations. Key challenges and future directions are identified, with a focus on precision materials processing with translation to clinical applications.