Fig. 2. Combinational antibacterial assay of GNC with antibiotics. (A) 24 h checkerboard results of the GNC with imipenem (Imp), oxacillin (Oxa), and erythromycin (Ery) (OD₆₀₀ values are given in the colour scale; a darker colour represents a higher bacterial concentration). The FICI was 1, 0.508, and 0.75 for GNC and Imp, Oxa, and Ery, respectively. (B) 48 h checkerboard results of GNC with Imp, Oxa, and Ery. The FICI was ∼0.5 for all three groups. This experiment revealed the combinational bactericidal effect of GNC with varied types of antibiotic. (C) Undiluted plate-coating results of MRSE colonies after treatment with PBS buffer (control), different concentrations of Ery/Imp/Oxa and 16 μg mL⁻¹ GNC to visually display changes in colonies. (D) Time-dependent killing curves demonstrate a superior antibacterial efficiency of the combination of GNC and Imp compared to their separate applications. PBS buffer (control), Imp only (2 μg mL⁻¹), GNC only (16 μg mL⁻¹), and a combination of GNC (16 μg mL⁻¹) and Imp (2 μg mL⁻¹) (n = 3, ** 0.01 < P < 0.05, ***P < 0.01 and ****P < 0.001).