Surface Modification And Osteogenic Properties Of Artificial Phalanges With Polyetheretherketone Based On FDM

The number of severe hand tissue defects caused by high-energy injuries is increasing in clinical practice.In particular,large-scale hand injuries can seriously affect hand function.With the continuous development and maturity of computer-aided design and 3D printing technology,the 3D-printed artificial prosthesis has been widely used in clinical practice.In order to achieve a better therapeutic effect,it is necessary to enhance the activity of the prosthesis to achieve better fusion with bone tissue.Among them,the biological activity,inhibition of inflammation,elastic modulus,and other characteristics of prosthesis materials will be related to their matching with bone tissue.Polyetheretherketone(PEEK)has excellent physicochemical,mechanical,and biocompatibility properties compared to other materials.Additionally,PEEK has a similar elastic modulus to human bone,which can effectively avoid the stress-shielding effect in the later stage of prosthesis transplantation.The aim of this study is to explore the biomechanical characteristics of each finger joint through medical three-dimensional image reconstruction and finite element technology.At the same time,Fused Deposition Modeling(FDM)technology was used to print PEEK into a personalized design of the distal phalanx of the index finger.The biological activity,biocompatibility,and osteogenic ability of the surface modification were further explored.The main contents are as follows:First of all,The finite element model of the index finger joint was established by Mimics software and Ansys finite element analysis software to simulate the stress distribution of PEEK material in each phalanx of the index finger under different static loads,and to provide a biomechanical basis for PEEK to be used as the index finger prosthesis material.Furthermore,a personalized distal phalanx of the index finger was fabricated by printing PEEK using FDM technology.Sulfonated PEEK(S-PEEK)was obtained by soaking the sample in a concentrated sulfuric acid solution.The sulfonation time was divided into five groups to form different nanothree-dimensional porous structures on the surface of the materials.After the sulfonation process was completed,Na OH was immersed to remove residual sulfuric acid.The physical and chemical properties of the implant prosthesis surface were determined by scanning electron microscope,energy dispersive spectrometer,and X-ray diffractometer.In addition,the surface hydrophilicity,surface roughness,and mechanical properties of the prosthesis before and after sulfonation were compared and analyzed.Finally,the implant was co-cultured with stem cells from human exfoliated deciduous teeth(SHED).The biological activity,biocompatibility,and osteogenic ability of the S-PEEK implant were detected by cell proliferation,adhesion,alkaline phosphatase(ALP)activity,and alizarin red staining.The finite element analysis results showed that when the PEEK index finger was applied with different loads along the radial direction of the phalanx,the peak stress distribution ranged from 0.37-5.96 MPa,which would not cause deformation due to excessive pressure.PEEK index finger implant meets certain mechanical and biomechanical properties requirements.After sulfonation treatment,the surface hydrophilicity of the PEEK implant was not significantly improved compared with the control group.The sulfonation time range of 1-8minutes can promote the formation of micropores on the surface of PEEK implants,significantly improve the surface roughness of PEEK materials,and have little effect on the mechanical properties of PEEK materials,which is suitable for its application in the field of implants.The adhesion and proliferation experiments of SHED cells showed that SHED cells could be effectively adsorbed on the PEEK surface,and significant cell pseudopodia formation was detected at the same time.Among them,S-PEEK2 showed the best biocompatibility.Semiquantitative analysis of ALP activity and alizarin red staining showed that the sulfonated 3D porous structure significantly promoted the osteogenic differentiation of SHED cells,and the osteogenic activity of S-PEEK2 was significantly higher than that of the other groups.The results of this study show that the PEEK index finger implant meets certain mechanical and biomechanical properties requirements.Sulfonation treatment can effectively improve the surface biological activity of PEEK implants,which provides preliminary evidence for the application of S-PEEK in orthopedics.