Sulfonated PEEK Influences Macrophage Adhesion And Inhibited Inflammatory Cytokine

ObjectivePEEK was modified by sulfuric acid treatment to form a new surface structure,and different surface structures and biological properties were observed.MethodsThe PEEK material surface with two different morphologies,3D mesh structure and 2D pore structure were obtained by controlling the reaction conditions.They were divided into three groups: control group(N),3D mesh group(3D)and 2D pore structure group(2D).Field emission scanning electron microscope,optical profilometer,Fourier infrared spectrometer and contact angle measuring instrument were used to observe the surface of each group of materials.In the in vitro cell experiment,scanning electron microscope was used to observe j774 a.1 cultured on the surface of each sample.BMDMs from primary mouse bone marrow were identified by flow cytometry(FCM),and the influence of each sample on survival activity was detected by flow PI staining.In cell and molecular experiments,the effects of material surfaces in each group on the secretion of BMDMs inflammatory factors were investigated in the inflammatory environment.Quantitative real time polymerase chain reaction(q RT-PCR)was used to detect pro-IL-1 and pro-caspase-1.Western blot was used to detect IL-1,pro-IL-1,caspase-1,and pro-caspase-1.In addition,ELISA was used to identify the content of IL-1 in the secreted supernatant of cells cultured on the surface of each group.ResultsMaterial surface: the polished PEEK material has a smooth surface.After sulfuric acid treatment,the surface of the 3D group has a three-dimensional mesh structure,while the surface of the 2D group has a 2D single-layer porous structure.Atomic force microscope(AFM)results showed that the height of smooth PEEK was-180.1nm to 170.8nm,showing a smooth performance.The height of the 3D group was from-390.5nm to 302.2nm,and that of the 2D group was from-395.8nm to 256.9nm.Optical profilometer was used to observe the surface roughness of the sample.The smooth PEEK roughness is 0.259 nm.After sulfonation,the roughness of the 3D group was 0.565 nm.Its roughness has increased.The roughness of the 2D group is 0.441 cm,which is smaller than that of the 3D group.In addition,the surface structure coverage rate of the 3D group and the 2D group was 89.7% and 95.44%,respectively.The surface structure was uniform.Fourier infrared spectroscopy observation showed that S=O symmetrical stretch was observed at the absorption peak of 1050cm-1 in the 3D group and the 2D group,and the absorption peak amplitude was more obvious in the 2D group.-O-H was found at the absorption peak of 3393cm-1,but not in the N group.Similarly,the absorption peak amplitude of the 2D group was greater than that of the 3D group.In the hydrophilicity test,the 3D group was the most hydrophobic,followed by the N group and the 2D group was the most hydrophilic.The results of the cytological experiments showed that the number of j774 a.1 adhered to the 2D group was higher than that of the untreated group and the 3D group,and the cells on the 2D group extended more pseudopodia.In addition,the purity of BMDMs mice was 94.8%.The PI staining rate of BMDMs in the blank control group was 1.98%,that in the smooth PEEK group was 2.79%,and that in the 3D and 2D groups was 2.75% and 2.16%,respectively.In the molecular experiment,q RT-PCR results showed that gene expression of pro-IL-1β group and pro-caspase-1 was the lowest in the 2D group and the highest in the 3D group(P < 0.05).Western blot results showed that the expression levels of mature IL-1β protein and caspase-1 protein in the 2D group were the lowest,while the expression levels of the 3D group were higher.There was no significant difference in intracellular inflammatory protein expression.The ELISA results of IL-1β in the cell supernatant showed that the secretion of IL-1β in the smooth PEEK group and the 3D group increased,but the secretion in the 2D structure group decreased significantly(P < 0.05).ConclusionsBy controlling the reaction conditions between the material and sulfuric acid,the sulfonic acid group was entered the PEEK chemical structure to obtain 3D mesh structure and 2D pore structure.PEEK with a 2D pore structure processes a high cell-adhesive and inflammatory regulation potential and may be a promising material used in dental implant.