Antibiofllm And Antibacterial Mechanism Research On Porous HAPw/n-ZnO Antibacterial Bone Restorative Material

[Objective] the hydroxyapatite whisker (HAPw) was modified by sol-gel method and pore forming agent, and the preparation of porous hydroxyapatite whisker /nano Zinc Oxide (HAPw/n-ZnO) antibacterial bone restorative material was prepared. To research the antibiofilm and antibacterial mechanism of porous hydroxyapatite whisker (HAPw)/nano zinc oxide (n-ZnO) bone restorative material in the absence of light, so as to lay a foundation for further research.[Materials and Methods] Established Staphylococcus aureus, Candida albicans, Streptococcus mutans, and Porphyromonas gingivalis biofilm model in vitro respectively. In the absence of light, biofilm inhibition assay and intracellular reactive oxygen species (ROS) measurement were performed in the same concentration gradient (0-2mg/ml) of the porous HAPw/n-ZnO material. Scanning Electron Microscope(SEM), fluorescence microscopy, Confocal Laser Scanning Microscope (CLSM) were employed to analyze the antimicrobial mechanism of porous HAPw/n-ZnO, Without porous HAPw/n-ZnO, inoculums was used as control.[Results] Four kinds of bacteria are competent to form biofilm. As the material concentration increases, four kinds of bacteria biofilm formation exhibited a gradual decrease and an increased intracellular ROS level in the absence of light, the difference were statistically significant(P< 0.05). Scanning electron microscopy (SEM) images revealed the treatment of the material decreased the bacteria adhesion and four kinds of biofilm formation. Composite material group exhibited morphologies of the bacteria abnormalities, cell structure disorder, bacterial cell membrane destruction, and the leakage of intracellular contents. Fluorescence microscope and CLSM images showed the experimental material group biofilm appeared higher proportions of red fluorescence.[Conclusions] In the absence of light the porous HAPw/n-ZnO materials has a certain degree of inhibition on Staphylococcus aureus, Candida albicans, Streptococcus mutans, and Porphyromonas gingivalis biofilm formation. The decrease of the interaction and adhesion of bacterial cells, and the biofilm is in the abnormal active condition, may partly explain the antibiofilm effect of the porous HAPw/n-ZnO antibacterial bone repair material. One of its possible antimicrobial mechanism is that the formation of ROS in the absence of light induced bacteria morphological changes, subsequently damaged the bacterial cell membrane, causing the leakage of intracellular contents.