Additively Manufactured Biodegradable Metal Implants for Bone Defect Repair

This work focused on the development of Mg and Zn based biodegradable metal bone implants including powder materials, digital design and additive manufacturing.  WE43, Zn-Mg, Zn-Li, Zn-Cu powders were fabricated into porous scaffolds by laser powder bed fusion with reliable formation. The mechanical properties, biocompatibility and biodegradability were systematically characterized. The effect of chemical compositions, porous structure and surface conditions were investigated and optimized. The tensile strength of WE43, Zn-1Mg and Zn-0.8Li reached to 300, 381 and 417 MPa. Machine learning-optimized scaffolds efficiently matched bone structure and modulus, and simultaneously enhanced their strength. Meta-materials scaffolds were further designed to enhance bone regeneration. High temperature oxidation resolved the rapid degradation of Mg scaffolds, enabling reliable load-bearing and controllable degradation. The released metal ions from degradation demonstrated critical influence on cell viability and osteogenesis, and was effectively modulated by alloying composition, porous structure and surface treatment. Additively manufactured biodegradable metal implants have been successfully applied to animal models with complicated bone defects including critical size, infection, and tumor, and demonstrated promising results. The customized Mg alloy implants have accomplished clinical application and successfully treated over 70 patients of periarticular bone defects. The inspiring outcome indicates significant clinical values of additively manufactured biodegradable metal bone implants.

Peng Wen, Tenured Associate Professor at Tsinghua University and current Deputy Chair of the Department of Mechanical Engineering, in charge of Academic Affairs. He received his doctoral degree from Hiroshima University, Japan. His research focuses on laser processing and additive manufacturing, especially laser additively manufactured biodegradable metals and their applications in bone defect repair. He serves as a member of the Special Committee on Medical Metallic Materials of the Chinese Society for Biomaterials, and an editorial board member of Bioactive Materials, International Journal of Bioprinting, and Chinese Journal of Medical Device Research and Clinical Practice. Please visit his official academic homepage for further information: https://me.tsinghua.edu.cn/en/info/1280/1927.htm