Fig. 6

ZnO-NPs loaded with various drugs showed important antibacterial activity against Gram-positive pathogenic bacteria. Briefly, bacteria (1  ×  10⁶) were incubated with different drugs conjugated with ZnO-NPs and nanoparticles alone for two hours at 37 °C as defined in Materials and Methods. Next, the cultures were ten-fold serially diluted and plated onto the nutrient agar plates. The plates were incubated for 24 h at 37 °C and enumerated the viable bacterial colonies on the next day. The results showed that drugs conjugated ZnO-NPs exhibited significant antibacterial activity against the Gram-positive bacteria. For negative control, bacteria were incubated in PBS alone whereas for positive control gentamicin (100 µg/mL) was used. The data are representative of several experiments performed in duplicate and expressed as the mean  ±  standard error, where (*) represent when P  ≤  0.05