Dual-Functional 3D-Printed Porous Titanium–Hydrogel Composite Scaffold With Mg2+ and ZIF-8 Release for Enhanced Bone Regeneration and Bacterial Inhibition

3D-printed titanium implants are extensively utilized in bone reconstruction. However, their bioinertness and lack of antibacterial activity increase risks of aseptic loosening and implant-associated infection—the primary causes of implant failure. To address these limitations, we developed a dual-functional 3D-printed porous titanium–hydrogel composite scaffold to enhance the osteogenic and antibacterial capacities of titanium. This composite scaffold was fabricated by integrating quaternized chitosan (QCS)/aldehyde-terminated Pluronic F127 (PF127-CHO) hydrogel loaded with magnesium ions (Mg 2+ ) and zeolitic imidazolate framework-8 (ZIF-8) into polydopamine-coated 3D-printed porous titanium scaffold. The composite scaffold exhibited sustained and controlled release of Mg 2+ and ZIF-8 with enhanced binding strength at titanium–hydrogel interface. In vitro experiments demonstrated that the composite scaffold possessed favorable biocompatibility, promoted the adhesion and proliferation of MC3T3-E1 cells, and facilitated their osteogenic differentiation through synergistic effect of Mg 2+ and ZIF-8. Furthermore, it also inhibited bacterial growth via synergistic action of QCS/PF127-CHO hydrogel and ZIF-8. In vivo experiments confirmed enhanced bone ingrowth into the composite scaffold and its effective antibacterial activity. In summary, this composite scaffold provides a promising strategy to simultaneously improve the osteogenic and antibacterial capacities of titanium implants.