Evaluation of the antibacterial and cytotoxic activities of Ag/ZnO nanoparticles loaded polycaprolactone/chitosan composites for dental applications

Bacterial adhesion to orthodontic brackets is a significant issue in orthodontic treatment. Most plaque control approaches rely on the patient’s cooperation which is not good enough to control the pathogenic oral microorganisms in most cases. Considering the growth rate of antibacterial resistance species, finding new antibacterial agents to control the oral microbial load seems necessary. This study aimed to evaluate the antibacterial and cytotoxic effects of Ag/ZnO NPs loaded PCL/CS composites.

Ag/ZnO NPs were synthesized and characterized using sol-gel and DLS, respectively. After preparing three concentrations of Ag/ZnO NPs, they were loaded on the scaffolds. The release of NPs was measured in the artificial saliva. The antibacterial activities of NPs were evaluated on the medium plates of S. aureus and S. mutants using the inhibition zone method and compared to the control group (scaffolds without Ag/ZnO NPs). The cytotoxic effects of NPs were assessed using fibroblasts with MTT assay and compared to the control group.

The results showed that Ag/ZnO nanoparticles have antibacterial properties that increase over time. The 25  µg/mL concentration of these NPs had the least effect on L929 fibroblasts.

The Ag/ZnO NPs loaded the PCL/CS scaffolds have controlled slow-released properties. These NPs have antibacterial effects on oral microfilms and can be used to control pathogenic oral microorganisms. Moreover, they are safe with no cytotoxic effects the fibroblast cells and can be used in the oral cavity and skin.