All-in-One 3D-Printed MXene/PLA/Icaritin (MXPI) Composite Scaffold Promotes Efficient Bone Repair for Intervertebral Fusion via NIR-Mediated Mild Photothermal Therapy (MPTT).

Achieving stable spinal fusion and efficient bone regeneration remains a significant challenge. Tissue-engineered materials offer a promising solution for enhancing bone repair. This study developed MXene/PLA/icaritin (MXPI) composite scaffolds by melt-blending Ti3C2Tx MXene nanosheets (with photothermal and drug-delivery functions), polylactic acid (PLA) resin, and the osteogenic agent icaritin (ICT). The composite granules were processed into fibrous materials via fused deposition modeling (FDM). Comprehensive characterization and comparative analyses were performed. In vitro experiments evaluated near-infrared (NIR)-mediated mild photothermal therapy (MPTT) for bone repair. To assess in vivo performance, scaffolds were implanted in rat tail vertebrae fusion models, with repair efficacy analyzed via micro-CT imaging and histopathology. Results demonstrate that MXPI scaffolds meet spinal implant requirements for mechanical properties, photothermal efficiency, and friction coefficient. Under NIR irradiation, they enabled MPTT-triggered uniform ICT release, significantly accelerating bone repair. Compared to control scaffolds, MXPI exhibited superior fusion efficiency and bone regeneration within identical observation periods. Thus, this NIR-responsive MXPI scaffold provides a feasible and effective strategy for enhancing bone repair in spinal fusion applications.