ABSTRACT
Objective@#To investigate the antibacterial property and biological activity of Ti dental implant with antimicrobial peptide Pac-525 coatings, and to study the effect of peptide Pac-525 coatings on Porphyromonas gingivalis's antibacterial performance and osteoblast proliferation and adhesion.@*Methods@#After ultrasonic micro arc oxidation, alkali treatment and silane treatment, forty-five pure titanium specimens were exposed to antibacterial peptide Pac-525 in different concentration (0.25, 0.50, 0.75 g/L). The titanium specimens in the control group were only treated with ultrasonic micro arc oxidation, alkali treatment and silane treatment. The morphologies of coatings were observed by scanning electron microscope (SEM), and the element changes were detected by energy spectrum analyzer. Orange acridine-ethidium bromide double staining was used to detect the average percentage of live bacteria and biofilm thickness, after the specimens in each group and Porphyromonas gingivalis were co-cultured for 72 hours. Cell counting Kit-8 method and immunofluorescence staining were used to test the proliferation of osteoblasts, the number and growth morphologies of adherent cells, respectively.@*Results@#SEM and energy spectrum analysis showed that the Pac-525 particles loaded on the surface of the coating, and the C and N elements in the Pac-525 coating group were significantly more than those in the control group. The average percentage of living bacteria in the control group, 0.25, 0.50 and 0.75 g/L antimicrobial peptides were 0.58%, 0.45%, 0.34% and 0.28%, respectively, and the difference between each group was statistically significant (P<0.05). The biofilm thickness of Porphyromonas gingivalis in 0.50 and 0.75 g/L antibacterial peptide group were (98.3±1.2) and (94.5±2.5) μm respectively, which were significantly less than those in control group and 0.25 g/L antibacterial peptide group [(117.6±1.5) and (118.0±1.3) μm] (P<0.05), respectively. The number of bone cell adhesion and proliferation of all antimicrobial peptides were significantly greater than those in the control group (P<0.05), and the cells stretched better.@*Conclusions@#The antibacterial peptide coating of titanium implants could inhibit the formation of bacterial biofilm. It had good antibacterial properties and could promote the adhesion and proliferation of osteoblasts.
ABSTRACT
BACKGROUND:The micro-arc oxidation technology can enhance the corrosion resistance of magnesium and its aloys to improve the biological properties of the surface. OBJECTIVE: In order to regulate the biological activity of medical pure magnesium, to modify the micro-arc oxidation coating by adding nano-SiO2 and nano-TiO2 into the plating solution, and to study the biological coating effects on osteoblast proliferation and differentiation. METHODS: Round magnesium sheets were divided into three groups, respectively treated with silicate electrolyte containing 7.5 g/L nano-SiO2 (nano-SiO2 group), 4.8 g/L nano-TiO2 (nano-TiO2 group), and nothing (control group). Passage 3 osteoblasts were seeded onto the specimen surface in the three groups to observe the early morphology, proliferation and alkaline phosphatase activity of osteoblasts. RESULTS AND CONCLUSION:Osteoblasts grew wel in the nano-SiO2 group and nano-TiO2 group, presenting with clear outline, and the cels were long spindle- and polygon-shaped. But in the control group, the cels grew poor in the specimen surface. Cel counting kit-8 test showed that the absorbance values and alkaline phosphatase activities were increased with time in the three groups. Compared with the control group, the proliferative activity was higher in the nano-SiO2 group and nano-TiO2 group at days 1, 3, 5 after seeding, while the activity of alkaline phosphatase was also higher in the nano-SiO2 group and nano-TiO2 group at days 3, 5 after seeding. These findings indicate the micro-arc oxidation coatings containing nano-SiO2and nano-TiO2 can promote osteoblast proliferation and osteogenetic activity, which have good biocompatibility.