Fig. 1. Surface microstructure of 850S and 950S. (a) Optical microscopy image, (b) SEM images. Scale bars, 50 µm.

Fig. 2. Characterization and biocompatibility assay. (a,b) HAADF-STEM images of (a) 850S and (b) 950S; scale bars, 200 nm. (c) The absorbance at 450 nm for the viability of MC3T3-E1 cells attached to the sample surface after 1, 4 and 7 days of culture. (d) The absorbance at 405 nm for ALP activity of MC3T3-E1 cells attached to the sample surface after 7 and 14 days of culture. (e) Western blotting bands of the expression of a series of vital osteogenesis-related proteins, including ALP, BMP-2, COL-1, OCN and OPN. (f) The concentration of copper ions released from 850S and 950S after 7, 14, 21 and 28 days of culture. (g) XRD patterns of 850S and 950S. *p < 0.05.

Fig. 3. Electrochemical test. (a) Open circuit potential of all the groups. (b) Bode phase diagrams. (c) Bode plot diagrams. (d) Nyquist plot diagrams.

Fig. 4. Bacterial colony-counting assay. (a) Images of S. aureus colonies for TC4, 850S and 950S grown on LB agar for 24 h. (b) Images of E. coli colonies for TC4, 850S and 950S were obtained and cultured under the above conditions. (c, d) Antibacterial rate of 850S and 950S against (c) S. aureus and (d) E. coli. *p < 0.05, ***p < 0.001.

Fig. 5. Bacterial viability assay. (a, b) Live/Dead fluorescent images of (a) S. aureus and (b) E. coli after dripping on the sample surface and coculturing for 24 h. Green label represents live bacteria, and red label represents dead bacteria. Scale bars, 100 μm.

Fig. 6. Radiological results after implantation. (a) X-ray radiographs were obtained at 1, 2, 4 and 6 weeks postoperatively to obtain a kinetic estimation of the level of osteomyelitis. (b) Anterior and lateral views of the micro-CT 3D reconstruction of each implant and cortical bone 6 weeks after surgery. The red area represents cortical bone, and the silver area represents the implant. (c) BV/TV for TC4, 850S and 950S. *p < 0.05.

Fig. 7. Histological results. (a) MB-AF staining in the TC4, 850S and 950S groups at 6 weeks postoperatively under low and high magnification. The red rectangle indicates cortical bone, the yellow rectangle indicates osteomyelitis, and the magnifications are shown beneath. Scale bars: upper, 500 µm; lower, 50 µm. (b) H&E staining in the TC4, 850S and 950S groups. The red rectangle indicates typical inflammatory cell aggregation, and the magnifications are shown beneath. Scale bars: upper, 100 µm; lower, 40 µm.