Abstract: Objective: To study the antibiofilm activity and antibacterial mechanism of porous hydroxyapatite whisker (HAPw)/nano zinc oxide (n-ZnO) bone restorative biomaterial. Methods: Staphylococcus aureus, Streptococcus mutans, and Porphyromonas gingivalis biofilm model were established in vitro respectively. Under darkness, biofilm inhibition assay and intracellular reactive oxygen species (ROS) measurement were performed in the same concentration gradient (0-2 mg/mL) of the porous HAPw/n-ZnO material. The scanning electron microscope was employed to analyze the material. Without porous HAPw/n-ZnO, inoculums was used as control. Results: As the material concentration increases, each concentration of porous HAPw/n-ZnO group (1.00, 1.25, 1.50, 1.75, and 2.00 mg/mL) relative to the control (0 mg/mL), three kinds of oral bacteria biofilm formation exhibited a gradual decrease and an increased intracellular ROS level under darkness. The difference was statistically significant (P＜0.05). Scanning electron microscopy (SEM) images revealed that the treatment of the material decreased the bacteria adhesion and three kinds of biofilm formation. Composite material group exhibited abnormal bacteria morphology and bacterial cell membrane destruction, which caused the leakage of intracellular contents. Conclusion: Porous HAPw/n-ZnO materials has a certain degree of inhibition under darkness on staphylococcus aureus, streptococcus mutans, and Porphyromonas gingivalis biofilm, and one of its antibacterial mechanism is the formation of reactive oxygen species (ROS).

Key words: Porous, HAPw/n-ZnO composite material, Reactive oxygen species, Antibacterial mechanism, Biofilm