Figure 4. Photodynamic antimicrobial activity of the CDs. (a)
Schematic illustration of the antibacterial effect of the CDs onE. coli and S. aureus under different conditions. (b-c)
Comparison of bacterial survival rate of E. coli upon treatment
with different concentrations of the CD for different times in the dark
(b) and under light irradiation (c). (d-e) Comparison of bacterial
survival rate of S. aureus upon treatment with different
concentrations of the CD at different times in the dark (d) and in the
light irradiation (e). (f-g) ROS
levels of E. coli (f) and S. aureus (g) upon treatment
with different concentrations of the CD at 30 min under light
irradiation and in the dark. The groups treated with
H2O2 were used as the positive control.
(h) Time courses of the normalized absorbance at 410 nm of the CDs,
DPBF, and the mixture of the CDs and DPBF under light irradiation and in
the dark. Note that the CD and DPBF used in the corresponding samples
were of 100 μg/mL and 100 μM in
final concentration, respectively.