Modification of 3D printed porous titanium implants with on-demand delivery of curcumin and stromal cell derived factor-1 for osseointegration improvement.

Porous titanium (Ti) implants manufactured via three-dimensional (3D) printing hold considerable promise in the reconstruction of bone defects. However, their osseointegration capacity requires enhancement, and existing techniques remain insufficient. The biofunctionalization of titanium implants-transforming their surface from biologically passive to osteoactive-has emerged as a paramount objective in implantology research. To improve osseointegration of 3D-printed porous Ti implants, this study proposes a novel cell-guided drug delivery system that enables cell recruitment, osteogenic differentiation, and local immunomodulation. Inspired by natural bone osteogenesis, an on-demand delivery system co-loading curcumin (Cur) and stromal cell-derived factor-1 (SDF-1) was designed. SDF-1 and Cur-loaded polycaprolactone (PCL) microspheres (Cur@PCL) were immobilized into the implant pores via a double-crosslinked alginate-chitosan hydrogel coating. The system's effects on osseointegration and immunomodulation were evaluated both in vitro and in vivo. Experiments demonstrated that the system enhanced early-stage cell recruitment via SDF-1 release, priming target cells for Cur activity. Subsequent Cur release induced M2 macrophage polarization and osteogenic differentiation. Furthermore, the SDF-1/Cur synergy potentiated implant osseointegration. In summary, this multifunctional porous implant integrated with a drug delivery system holds clinical potential for patients requiring bone reconstruction with low bone mass.