| Objective: Polyetheretherketone is widely used in the field dentistry because of its elastic modulus close to human cortical bone,excellent chemical stability,reliable biological safety,X-ray transmission,and non-influencing imaging during nuclear magnetic resonance,for example,crowns,fixed bridges,healing abutments,abutment screws,etc.As an open environment with bacteria,the oral cavity has higher requirements for the antibacterial property of the material.However,as a biologically inert material,pure PEEK does not have antibacterial properties.When it is used in the oral cavity,once infections happened and other problems occurred,the success rate of treatment will be significantly reduced.In order to improve the antibacterial performance of the PEEK surface,this experiment synthesized ZnO/GO by a one-step method,then prepared it on the sulfonated PEEK surface by dip coating,and performed characterization and analysis to screen the appropriate ZnO/GO mass ratio and dip coating conditions.The biological safety and antibacterial properties were evaluated to provide the theoretical basis for the application of polyetheretherketone in the oral cavity.Methods: 1.In this experiment,ZnO/GO with mass ratio of 3:1,4:1,and 5:1 were prepared and bonded to the surface of polyetheretherketone by dip-coating.2.With PEEK and sulfonated PEEK as the control group,the surface morphology of the sample was detected by scanning electron microscope and atomic force microscope;the surface chemical composition was analyzed by X-ray photoelectron spectroscopy and Raman spectroscopy;the surface of hydrophilic properties were analyzed by water contact angle.The samples for biological testing are screened outthrough the analysis of the physical and chemical properties of the samples.3.Evaluate the biological safety of the sample by evaluating the adhesion state of the cells on the sample surface and the CCK-8 method.After culturing L929 on the sample surface for 6 hours,the cell status was observed by scanning electron microscope.The sample extract was prepared according to the GB/T 16886.12-2017 standard,and the cell proliferation activity was detected by the CCK-8 method.4.The PEEK,SPEEK and ZnO/GO-SPEEK disks were co-cultured with three kinds of peri-implantitis-related pathogenic bacteria,which are S.sanguinis,F.nucleatum and P.gingivalis.The antibacterial activity of the disks were evaluated by the inhibition zone.A single species of biofilm was constructed on the sample surface,and the biological metabolic activity of the bacteria in the biofilm was detected by the MTT method;the inhibitory effect of the material on the bacterial biofilm was evaluated by the scanning electron microscope and the colony-forming unit method.Results: 1.Surface morphology was detected by scanning electron microscope and atomic force microscope.Sulfated PEEK forms a three-dimensional porous structure on the surface.After being modified by ZnO/GO,most of the porous structure is covered by ZnO/GO.The ZnO crystals of the 3-ZnO/GO-SPEEK group are uniformly distributed on the surface of graphene oxide in a needle-like shape.The 4-ZnO/GO-SPEEK group showed that needle-like zinc oxide crystals were wrapped by GO and formed petal-like structures.The ZnO on the surface of 5-ZnO/GO-SPEEK group is completely wrapped inside GO.2.The surface roughness of the sample before and after modification was revealed by atomic force microscope.It was found that sulfonation can reduce the roughness of PEEK(p <0.05)and make the surface more uniform.In the ZnO/GO modified group,the roughness increases by the increase of the mass ratio of zinc oxide.3.Through Raman spectroscopy and XPS analysis of ZnO/GO modified PEEK,it can be found that ZnO has been successfully hybridized with GO and successfully loaded on the surface of PEEK.At the same time,it was screened out that when the mass ratio of ZnO/GO is 4:1,the Zn element bound on the PEEK surface is the most.When the dip coating time is 25 min,the zinc content of coating is the highest and the most stable.4.The water contact angle increase in hydrophobicity on the surface of the sulfonated PEEK compared to PEEK.Samples in the 3,5-ZnO/GO-SPEEK group showed similar hydrophobicity.Samples in the 4-ZnO/GO-SPEEK group showed the best hydrophily.5.According to SEM images and CCK-8 analysis,ZnO/ GO modified SPEEK is with good biosecurity.6.In the inhibit zone test,ZnO/GO-SPEEK showed an obvious bacteriostatic ring(5mm±1.41 mm,n = 3)on the P.gingivalis plate.It proves that ZnO / GO-SPEEK has a more obvious antibacterial effect on P.gingivalis.7.MTT results show that compared with PEEK and SPEEK,ZnO / GO-SPEEK can significantly inhibit the metabolic activity of the pioneer bacterium S.sanguinis,which is beneficial to reduce the formation of plaque biofilm in the early stage.ZnO / GO-SPEEK can significantly inhibiting the metabolic activity of P.gingivalis,the main pathogen of peri-implantitis,is of great significance for the prevention and treatment of peri-implantitis.8.It is found that ZnO / GO-SPEEK can inhibit the formation of S.sanguinis bacterial biofilm by observing the biofilm on the surface through the colony forming unit count and scanning electron microscopy.As to F.nucleatum and P.gingivalis,the number of bacteria in the surface bacterial biofilm in the SPEEK group is the most,followed by PEEK,and ZnO/GO-SPEEK is the least.Similarly,scanning electron microscopy showed that there was almost no adhesion of P.gingivalis on the ZnO/GOSPEEK samples.It can be seen that the modification of SPEEK by ZnO/GO can effectively reduce the colonization of early pioneer bacteria and can effectively inhibit the growth of P.gingivalis,which is of great significance for the prevention and treatment of peri-implantitis.Conclusion: 1.In this experiment,ZnO/GO with a mass ratio of 3:1,4:1,and 5:1 was successfully prepared and bonded to the surface of PEEK by dip coating.2.Through the analysis of physical and chemical properties,this experiment screened out that when the proportion of ZnO/GO is 4:1,the surface of PEEK binds the most Zn element.When the dip coating time is 25 minutes,the zinc content of the coating is the highest and the most stable.3.The samples of 4-ZnO / GO-SPEEK group showed the best hydrophilicity(41.7°±5.164°).4.In this experiment,the biological safety of ZnO / GO modified SPEEK was tested,and it was found that 4-ZnO / GO-SPEEK has good cell compatibility and biological safety.This experiment proves that ZnO/GO-SPEEK has obvious antibacterial effect on P.gingivalis,the main pathogen of peri-implant inflammation,and can reduce the colonization of pioneer bacterium S.sanguinis,and inhibit the formation of plaque biofilm.The prevention and treatment of peri-implantitis is of great significance. |
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