4D printing in dynamic and adaptive bone implants: Progress in bone tissue engineering

The emergence of 4D printing has revolutionised tissue engineering technology by integrating dynamic and adaptive properties to previously static 3D-printed structures. This advancement is particularly noteworthy in the domain of bone tissue engineering (BTE), where accurate replication of the dynamics of real bone is essential for complex tissue structures. The article investigates the utilization of 4D printing techniques in the field of BTE, with a specific focus on the incorporation of stimuli-responsive materials, shape-memory scaffolds, and bio-inks to facilitate the fabrication of dynamic bone implants. The use of stimuli-responsive hydrogels, shape-memory polymers, and sophisticated bio-fabrication methods enables the creation of bone tissue structures capable of self-remodeling and adapting after being implanted. These structures have demonstrated potential in the personalized correction of bone defects and the possibility for the extensive deployment of bone graft replacements. The implementation of 4D printing in BTE is a notable breakthrough that opens novel opportunities for customized and dynamic bone implants. Additional research and development are necessary to overcome the existing constraints, namely in attaining reliable functional changes and guaranteeing the scalability of these technologies for clinical use.