NiTi alloys produced through additive manufacturing technology exhibit unique shape memory effects and the capability to accurately form complex structures, making them promising materials for bone implants. However, the bioinert nature of NiTi alloys and their limited antibacterial properties increase the risk of implant loosening and infection following surgery, complicating treatment efforts. To address this issue, we propose the development of a biocompatible and bacteriostatic DCPD-PCL-GO coating on the surface of alloy using electrochemical deposition and dip-pulling methods. This coating not only enhances corrosion resistance but also inhibits nickel ion release. We investigated the corrosion resistance, biocompatibility, and photothermal therapy (PTT) capabilities under near-infrared irradiation of composite coatings with varying graphene oxide content. The safe concentration of doped graphene oxide was ultimately determined. Our results indicated that doping with 150 mg of graphene oxide yielded the best corrosion resistance (3.8 ± 0.8 × 10⁻⁹ A/cm²) while maintaining a high cell survival rate (101%). Under near-infrared irradiation, the bacteriostatic rates against Staphylococcus aureus and Escherichia coli (in vivo and in vitro) exceeded 80%. Notably, the near-infrared-triggered bacteriostatic strategy demonstrated good biosafety in vivo settings, effectively reducing the inflammatory response while ensuring the safety of normal tissues. This modified method has an important application prospect in the photothermal treatment of postoperative infection.

Additive manufacturing of NiTi alloys exhibits high precision forming characteristics alongside excellent mechanical properties, making them highly regarded for medical implants. However, their insufficient corrosion resistance, biocompatibility, and antibacterial performance limit their clinical application. Herein, the disulfide-modified polyurethane (PU) coating was fabricated for the surface of NiTi alloys, incorporating MX@TA nanosheets to bolster corrosion resistance, self-healing capabilities, biocompatibility, and antibacterial properties. The self-healing performance of the PUS@MT coating is enhanced by the reformation of dynamic disulfide bonds, together with the formation of strong hydrogen bonds and metal–coordination interactions. Meanwhile, the corrosion resistance of the PUS@MT coating is improved through the synergistic effects of its self-healing capability and the “labyrinth effect” of MX@TA nanosheets. In vitro cell experiments demonstrated that the PUS@MT coating significantly promoted cell growth and proliferation, with cell viability reaching up to 98%. After exposure to near-infrared (NIR) light for 10 min, the PUS@MT coating exhibited excellent antibacterial activity against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with inhibition efficiencies exceeding 95%. Overall, this composite coating demonstrates synergistically enhanced self-healing ability, antibacterial performance, and biocompatibility, providing a promising strategy for the surface modification of NiTi alloy implants.