Figure 4. Stability of the paeonol-coated PDMS surface measured by its antibacterial effect against E. coli DH5α.

Bacteria were observed 1, 2 and 3 h after culture. The uncoated PDMS surfaces were used as controls. (a) Antibacterial effect of the coated PDMS surfaces prepared with paeonol of different concentrations. (b) Antibacterial effect of the paeonol-coated PDMS surfaces against water rinsing. (c) Antibacterial effect of the paeonol-coated PDMS surfaces after incubation in water for different time spans. At least three experimental repetitions were carried out for each data point. The difference between sample groups and the control group was tested by Student’s t-test (*0.01 < p < 0.05, **0.001 < p < 0.01, ***p < 0.001). The length of scale bar is 100 μm.