Advances and prospects of 3D printed antibacterial bone implants: A systematic review

Bone defect is a serious problem for clinical orthopedics, and the construction of bone implants with ideal size, shape, structure and demanded biofunctions, etc., is of great importance for bone repairs. Especially, the endowment of implants with antibacterial activities is a promising strategy for the potential occurrence of infections during and/or after bone graft surgery. Three-dimensional (3D) printing, a hot technological strategy in tissue engineering, is increasingly applied in manufacturing various personalized, controlled and precise bone implants. However, significant challenges remain in overcoming infections. In this systematic review, different 3D-printed antibacterial bone implants are critically reviewed, and a general summary of the latest researches is systemically expounded, in which different antibacterial agents are involved: (i) inorganic; (ii) organic micromolecule; (iii) organic macromolecule; (iv) "function-assist" materials. Moreover, designments of printing processes, loading methods of antibacterial agents, functional treatments of bone implants, and related antibacterial mechanisms are also discussed. Overall, it is demonstrated that antibacterial 3D-printed bone implants exhibit excellent bone regeneration and bacterial resistance. Especially, the limitations and future expectations on the strategies and the development of the "programmed" antibacterial implants, are highlighted. This systematic review can provide a comprehensive understanding and insightful guidance for further exploring promising antimicrobial bone implants.