Fig. 4
Antibacterial activity of BMP-Ag and Ag-Fe3O4 NPs. A Colony-forming ability of S. aureus, E. coli and P. aeruginosa after exposure to successive dilutions of Ag, Ag-Fe3O4, BMP-Ag and BMP NPs for 12 h and 24 h at room temperature. At a concentration of 2.0 mg mL−1, BMP-Ag and Ag-Fe3O4 NPs both exhibited antibacterial activity. A low concentration of NPs can inhibit bacterial growth with increased incubated time. Photographs of bacterial colonies formed by S. aureus (B), E. coli (D), and P. aeruginosa (F) after treatment with 2.0 mg mL−1 BMP, 100.0 µg mL−1 ampicillin, 20.0 µg mL−1 gentamicin, 2.0 mg mL.−1 BMP-Ag, and Ag-Fe3O4 NPs. Antimicrobial activity statistics of BMP, ampicillin, gentamicin, BMP-Ag, and Ag-Fe3O4 NPs to S. aureus (C), E. coli (E), and P. aeruginosa (G). Comparison with antibiotics ampicillin and gentamicin, BMP-Ag and Ag-Fe3O4 NPs displayed a one hundred percent antibacterial effect. Data are presented as the mean ± s.d. (n = 3 biological replicates per group) and statistically analysed using the two-sided Student’s t-test: *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001