Preparation And Bioactivity Activity In Vivo Of Molybdenum/hydroxyapatite Modified Polyether Ether Ketone Materials

Objective:Polyether ether ketone（PEEK）is an inert biomaterial with poor antibacterial and osteogenic activity in the body.In order to improve the biological activity of PEEK material,this experiment formed a layer of molybdenum disulfide（Mo S₂）nanosheet and bone-induced nanohydroxyapatite（HA）on the surface of PEEK.Finally,we synthesized a new HA-Mo S₂-PEEK（HMP）composite biological material,and further explored the antibacterial and osteogenic activity of the composite material in vivo.Methods:Through two steps of hydrothermal reaction,a new layer of HA-Mo S₂-PEEK（HMP）composite material with photothermal conversion efficiency and bone induction was synthesized on the surface of the polyether ether ketone material.Scanning electron microscopy（SEM）,X-ray photoelectron spectrometer（XPS）,X-ray diffractometer（XRD）and antennal tester were used to analysis the material characterization.The photothermal effect of the material in vitro was evaluated by illuminating the sample surface with near-infrared light（NIR）and detected using the infrared imaging camera.To study the photothermal activity of the material in vivo,we implanted the samples into the rats and irradiated the material implantation sites with near-infrared light.In in vivo animal experiments materials,dividing into the PEEK,MP and HMP,were implanted into a rat skull defect model after infection with Staphylococcus aureus.We irradiated with near infrared light（NIR）for 15 min at 24 hours after infection,and feed 4 weeks.We main observed Eating,mental state and wound healing for the rats after the surgery,recording the weight within one week.Materials were removed under sterile conditions after 4 weeks.Taking germiculture evaluated the qualitative and quantitative evaluation of bacteria.At the same time,the soft group around the material was stained for HE and Giemsa to observe the infiltration of inflammatory cells in the surrounding soft tissue to reflect the antibacterial properties of the material in vivo.The cranial tissue around the material scanned by Micro-CT after removed from the rat.Then the skull was performed for reconstruction,and the region of interest was selected for quantitative analysis of osteogenesis related indicators.Each part of the skull tissue was prepared into hard tissue sections after HE and methylene blue-acid magenta staining to evaluate the osteogenic activity in vivo.Results:Through two steps hydrothermal reaction,we finally get the HMP composite of gray colour.The SEM observed that the surface void of MP and HMP was filled with numerous crystals,and HA crystals were observed on the HMP sample.The XRD results indicated that the presence of HA crystals and Mo elements was detected on the surface of the HMP samples.The XPS examination showed that the Mo,Ca,P,S,showed on the HMP sample;but only Mo and S showed on the MP sample.Contact angle detection showed that the contact angles of both MP and HMP were larger than those of the PEEK.The photothermal experiments showed that the MP and HMP samples showed good photothermal activity in vitro and vivo.The general observation of rats showed that the mental state of the MP and HMP groups were significantly better than PEEK group.By recording rat body weight,we found that MP and HMP groups gained significantly faster than PEEK rats.The observation of the wound condition showed that the wound in the PEEK group were poorly healing,with redness,rupture and implanted material exposed,while the MP and HMP groups were healed well.Qualitative evaluation of bacteria showed that after 24 hours of solid culture,numerous colonies grew on the media in the PEEK group,while almost no bacterial grow in the MP and HMP groups.After48 hours in liquid medium,the PEEK group become obvious turbidity,while the liquid medium in MP and HMP groups were still clear.The results of bacterial quantitative evaluation showed a large number of bacterial grow in PEEK group,but only a small number grow in MP and HMP groups.HE staining and Giemsa staining of the peripheral soft tissues showed a large amount of inflammatory cell infiltration are in the surrounding soft tissues of the PEEK group,including mainly neutrophils and monocytes,while less inflammatory cell infiltration infiltrates in the MP group and HMP group.Micro-CT scan results showed a large amount of new bone formed in the skull defect area in the HMP group,while only very little new bone tissue formed in the defect area in the PEEK and MP groups.According to the new bone volume（BV）,bone surface area（BS）,bone volume/tissue volume（BV/TV）,trabecular thickness（Tb,Th）,trabecular number（TB,N）,the HMP group was significantly increased compared with PEEK group and MP group.HE and methylene-acid magenta staining of bone tissue showed that a little of preimplant inflammatory cell infiltration and peripheral fiber hyperplasia were in the MP group and HMP group,but a large amount of new bone tissue and mineralized tissue formed around the implant in the HMP group.In vivo biosafety evaluation showed that the HMP material has a good biological safety in vivo.Conclusion:This HMP biomaterials with good photothermal activity synthesized by hydrothermal method.Due to the loading of photothermal agent Mo S₂and osteogenic inducer HA,good photothermal antibacterial properties and osteogenic activity were shown in vivo.This new HMP biomaterial provides a strategy for the PEEK modification and expects to be used in the future.