Polydopamine/Cerium Oxide Nanoparticle Coating on 3D-Printed Photothermal Shape-Memory Bone Scaffolds for Synergistic Antibacterial and Antitumor Applications

Addressing complex bone defects associated with infection and tumors requires advanced surface and biointerface engineering of biomaterials. This study presents a surface functionalization strategy for constructing a multifunctional coating on a 3D-printed shape-memory polymer composite (PLA/PEG/MoS 2 ) substrate. Utilizing a polydopamine (PD)-mediated deposition process, cerium oxide nanoparticles (CeO 2 NPs) were uniformly immobilized onto the scaffold surface to create a tailored, functionally active coating. This coating markedly altered the surface physicochemical properties, reducing the water contact angle from approximately 81° to 48°, and enhanced interfacial biomineralization and the osteoblastic response of MC3T3-E1 cells. Moreover, the designed substrate-coating architecture integrated bulk photothermal responsiveness with surface-mediated nanoparticle activity, enabling a synergistic therapeutic mode at the biointerface. Under near-infrared (NIR) irradiation, the photothermal heat generated by the MoS 2 -incorporated scaffold triggered shape-memory recovery for adaptive defect fitting while simultaneously amplifying the antibacterial and antitumor efficacy of the PD/CeO 2 coating. As a result, the multifunctional scaffold achieved antibacterial rates of 92% against E. coli and 94% against S. aureus, together with a 92% ablation rate of human osteosarcoma (HOS) cells. Overall, this work demonstrates a potential functional-coating strategy for engineering a multifunctional biointerface on 3D-printed bone scaffolds, integrating surface bioactivity, NIR-triggered shape-memory behavior, and synergistic photothermal/nanoparticle therapy. These findings provide a promising design for functional coatings and surface-engineered biomaterials in the treatment of complex bone defects.