The additive manufacturing NiTi alloy surface modification scheme can be used for photothermal treatment and overcoming implant infection

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.