A multilayered Zn/CuSe/Zn heterostructural composite for orthopedic implants: Notable work-hardening, antibacterial, and antitumor properties

Building on the well-established antitumor properties of selenium (Se), the incorporation of Se into zinc (Zn)-based composites holds substantial potential for antitumor implant applications. Nevertheless, the pronounced disparity in melting points between Zn and Se renders conventional direct smelting methods impractical for fabricating Zn-Se composites. Furthermore, the prevalent work-softening tendency of Zn-based materials constitutes a major barrier to their clinical translation. Here, we report an effective strategy in which Zn sheets coated with copper selenide (CuSe) powder were used as precursors to fabricate multilayered Zn/CuSe/Zn heterostructural composites through the accumulative roll bonding (ARB) technique, providing a promising approach to overcoming processing challenges. The microstructure of the Zn/CuSe/Zn composite primarily consisted of the η-Zn phase, accompanied by ε-CuZn₅ and ZnSe intermetallic compounds. After 14 ARB passes and subsequent annealing treatment, the composite evidenced 246 ± 2 MPa for yield strength, 262 ± 3 MPa for ultimate tensile strength, and 12.2 ± 0.3% for elongation, along with noticeable strain hardening during tensile deformation. The Zn/CuSe/Zn composite samples exhibited a moderate corrosion rate of 60.23 ± 0.26 μm/year in electrochemical testing and a degradation rate of 38.12 ± 3.01 μm/year in Hanks' solution. Although some differences exist between the two results, the overall trend is consistent. The composite displayed strong antibacterial activity against Staphylococcus aureus (S. aureus), evidenced by an inhibition zone diameter of 3.21 ± 0.01 mm and colony-forming unit count of 42 ± 6. Furthermore, the composite exhibited favorable biocompatibility with MC3T3-E1 osteoblastic cells while exerting pronounced growth-inhibiting effects on MG63 osteosarcoma (tumor) cells. The Zn/CuSe/Zn composite demonstrates strong potential for antitumor implant therapy due to its potent overall combination of properties relating to mechanical characteristics, degradation capability, and biofunctionality. STATEMENT OF SIGNIFICANCE: This work reports the fabrication of multilayered Zn/CuSe/Zn heterostructural composites via the accumulative roll bonding (ARB) technique which exhibit notable biocompatibility, bone-regenerating properties, as well as antibacterial and antitumor capabilities. After 14 ARB cycles followed by annealing treatment, the Zn/CuSe/Zn composite material demonstrated significant work-hardening behavior, achieving a yield strength of ∼246 MPa, an ultimate tensile strength of ∼262 MPa, an elongation of ∼12.2%, and a moderate degradation rate of 38.12 ± 3.01 μm/year. Furthermore, the composite exhibited pronounced antibacterial activity against S. aureus, promoted osteogenic differentiation in pre-osteogenic MC3T3-E1 cells, and displayed remarkable antitumor efficacy against MG63 osteosarcoma cells. Owing to its suitable mechanical performance and multifunctional biological properties, this multilayered Zn/CuSe/Zn heterostructural composite holds considerable promise for orthopedic applications.