From Static Scaffolds to Responsive Implants: 3D-Printed Field-Active Bioceramics for Adaptive Bone Regeneration

Extensive bone defects complicated by infection, malignancy, or metabolic disorders remain a critical clinical challenge, as conventional calcium phosphate bioceramics provide only passive osteoconductive support. The integration of additive manufacturing with external physical stimuli, such as mechanical, piezoelectric, photothermal, magnetothermal, and ultrasonic, has catalyzed a paradigm shift from static scaffolding to responsive therapeutic platforms. This review examines how advanced techniques, including digital light processing (DLP), direct ink writing (DIW), and two-photon lithography (TPL), enable precise architectural programming of porosity, topology, and compositional gradients, establishing the physicochemical foundation for efficient field coupling. We dissect the mechanisms by which field-active bioceramics transduce external stimuli into bioelectrical, thermal, and mechanical cues, activating the mechanotransduction pathway that orchestrates osteogenic differentiation, immunomodulation, angiogenesis, and antibacterial activity. Particular emphasis is placed on multifunctional strategies, including tumor ablation-to-regeneration transitions, antibacterial-to-osteogenic modality switching, and 4D-printed shape memory architectures, alongside emerging self-powered systems harvesting endogenous mechanical energy. By elucidating the synergistic interplay among scaffold structure, material composition, and external field stimulation, this review establishes design principles for next-generation biomaterials that adaptively respond to complex bone-defect microenvironments.