Figure 5. Antibacterial function of t-ZnO-laden GelMA hydrogels compared with t-ZnO powder.

(A) The schematic diagram of bacterium and t-ZnO-interactions via oxidative stress, DNA damage and lipid peroxidation, which all damage the bacteria. (B and C) Photographs of cultured samples on the LB-agar after incubation for 12 hours. For both S. aureus and P. aeruginosa, no zone of inhibition was detected. (D) The number of colony forming units of S. aureus and P. aeruginosa cultured on t-ZnO-laden GelMA composite hydrogels. (n = 3, **p < 0.001). (E) The number of colony forming units after exposition to t-ZnO powders with and without H₂O₂-treatment. A significant decrease in bacterial activity can be seen for all experiments containing t-ZnO after 24 hours. S. aureus is completely inactive, while the amount of colony forming units for P. aeruginosa is significantly decreased after 24 hours. (n = 3, ****p < 0.0001). (F) Inhibition zone tests for 2% H₂O₂-treated t-ZnO hydrogels. Inhibition zones were found for both S. aureus and P. aeruginosa, for the latter only a reduction in bacteria population density for the former complete inactivation can be observed (n=9).