Dental implant is an effective method in the treatment of missing teeth.The process of osseointegration of implant teeth involves the coordinated operation of immune system and bone system.The interaction between cell...Dental implant is an effective method in the treatment of missing teeth.The process of osseointegration of implant teeth involves the coordinated operation of immune system and bone system.The interaction between cells is closely related to bone formation and repair.Exosomes are important intercellular communication molecules.They were originally found in the supernatant of sheep erythrocytes cultured in vitro.They are micro vesicles with a diameter of 40~150 nm.They exist in a variety of cells and body fluids.They enter the target cells by endocytosis and transport,affecting the expression of cell genes and changing the fate of cells.It has an important regulatory function in the microenvironment of implant bone binding.It plays a role in bone remodeling through small molecular RNA,specific proteins and other growth factors secreted by different cells.This article reviews the role of bone derived cellderived exosomes in bone remodeling and their function in implant osseointegration.展开更多
Objective To observe the effect of high positive acceleration(+Gz) environment on dental implant osseointegration in a rabbit model and to investigate its mechanism.Methods Forty-eight New Zealand white rabbits were r...Objective To observe the effect of high positive acceleration(+Gz) environment on dental implant osseointegration in a rabbit model and to investigate its mechanism.Methods Forty-eight New Zealand white rabbits were randomly divided into 6 groups. The rabbit’s mandibular incisors were extracted and 1 implant was placed in each socket immediately. After 1 week of rest, the rabbits were exposed to a high +Gz environment, 3 times a week. The rabbits were sacrificed at 3 weeks(2 weeks +Gz exposure), 5 weeks(4 weeks +Gz exposure), and 12 weeks(4 weeks +Gz exposure and 7 weeks normal environment) after surgery, respectively. Specimens were harvested for micro-CT scanning, histological analysis, and real-time polymerase chain reaction examination.Results Compared with those in the control group, the mRNA expression levels of bone morphogenetic protein-2(BMP-2), osteopontin(OPN), and transforming growth factor-β1(TGF-β1)were significantly lower(P < 0.05), while the mRNA expression level of receptor activator of nuclear factor κB ligand(RANKL) and the RANKL/osteoprotegerin(OPG) ratio were significantly higher(P < 0.05)at 3 weeks;values of bone volume fraction, trabecular number, bone-implant contact(BIC), and TGF-β1 and OPG mRNA expression levels were significantly lower(P < 0.05), and the value of trabecular separation, RANKL mRNA expression level and RANKL/OPG ratio were significantly higher(P < 0.05) at 5 weeks;and the value of BIC was still significantly lower(P < 0.05) at 12 weeks in the experimental group.Conclusion Early exposure to the high +Gz environment after implant surgery might have an adverse effect on osseointegration, and its mechanism could be related to the inhibition of osteoblast activity and promotion of osteoclast activity.展开更多
Following dental implantation,the characteristic bacterial milieu of the oral cavity may lead to peri-implant inflammation,which can negatively impact osseointegration and cause implant failure.To improve soft tissue ...Following dental implantation,the characteristic bacterial milieu of the oral cavity may lead to peri-implant inflammation,which can negatively impact osseointegration and cause implant failure.To improve soft tissue sealing around the implant,enhance osseointegration,and improve implant success rates,this paper proposes a composite multifunctional coating(PHG)prepared using gelatin and polydopamine/hydroxyapatite nanoparticles,investigates the effects of this novel coating on cell adhesion,proliferation,antibacterial activity,osteogenic differentiation,and evaluates its immune-related properties.The PHG coating was proved to have satisfactory hydrophilicity and wettability for cell attachment.Furthermore,it improved the expression of adhesion-related genes and proteins in human gingival fibroblasts,indicating its adhesion-promoting effect.Additionally,bone marrow mesenchymal stem cells exhibited strong osteogenic differentiation potential and mineralization on PHG-coated surfaces.Notably,the PHG coating exhibited antibacterial activity against Streptococcus mutans,as well as anti-inflammatory effects,potentially via the regulation of macrophages.Therefore,the proposed PHG coating may promote soft tissue sealing and bone bonding,providing a potential strategy for the surface modification of dental implants.展开更多
In this work, we analysed 56 clinically failed and retrieved implants by means of scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and histological studies. The surface contamination was comp...In this work, we analysed 56 clinically failed and retrieved implants by means of scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and histological studies. The surface contamination was compared to that of unused control implants and with that of the same implants after cleaning in a basic medium. The surfaces of the unused implants presented considerable contamination. In particular, high levels of carbon were detected. The nature of this C was elucidated by XPS analysis of the lubricant used in the machining process. The same contamination was observed in the retrieved implants. Histological studies were carried out by means of light microscopy. Fibrosis and granulomatous lesions were detected in the tissues. XPS analysis indicated the presence of traces of other elements (Na, Ca, Zn, S, F, etc.) that were not related to impurities in cpTi. We examined a cleaning process in a basic medium that eliminates the organic components of the implant surfaces. The cleaned implants were implanted in the patients and the results were excellent. None of the implants failed in following 7 months.展开更多
In our previous studies, a novel cortex-like Ti O2 coating was prepared on Ti surface through micro-arc oxidation(MAO) by using sodium tetraborate as electrolyte, and the effects of the coating on cell attachment were...In our previous studies, a novel cortex-like Ti O2 coating was prepared on Ti surface through micro-arc oxidation(MAO) by using sodium tetraborate as electrolyte, and the effects of the coating on cell attachment were testified. This study aimed to investigate the effects of this cortex-like MAO coating on osseointegration. A sand-blasting and acid-etching(SLA) coating that has been widely used in clinical practice served as control. Topographical and chemical characterizations were conducted by scanning electron microscopy, energy dispersive X-ray spectrometer, X-ray diffraction, contact angle meter, and step profiler. Results showed that the cortex-like coating had microslots and nanopores and it was superhydrophilic, whereas the SLA surface was hydrophobic. The roughness of MAO was similar to that of SLA. The MAO and SLA implants were implanted into the femoral condyles of New Zealand rabbits to evaluate their in-vivo performance through micro-CT, histological analysis, and fluorescent labeling at the bone-implant interface four weeks after surgery. The micro-CT showed that the bone volume ratio and mean trabecular thickness were similar between MAO and SLA groups four weeks after implantation. Histological analysis and fluorescent labeling showed no significant differences in the bone-implant contact between the MAO and SLA surfaces. It was suggested that with micro/nanostructure and superhydrophilicity, the cortex-like MAO coating causes excellent osseointegration, holding a promise of an application to implant modification.展开更多
This study aimed to examine the biocompatibility of calcium titanate(CaTiO_3) coating prepared by a simplified technique in an attempt to assess the potential of CaTiO_3 coating as an alternative to current implant co...This study aimed to examine the biocompatibility of calcium titanate(CaTiO_3) coating prepared by a simplified technique in an attempt to assess the potential of CaTiO_3 coating as an alternative to current implant coating materials. CaTiO_3-coated titanium screws were implanted with hydroxyapatite(HA)-coated or uncoated titanium screws into medial and lateral femoral condyles of 48 New Zealand white rabbits. Imaging, histomorphometric and biomechanical analyses were employed to evaluate the osseointegration and biocompatibility 12 weeks after the implantation. Histology and scanning electron microscopy revealed that bone tissues surrounding the screws coated with CaTiO_3 were fully regenerated and they were also well integrated with the screws. An interfacial fibrous membrane layer, which was found in the HA coating group, was not noticeable between the bone tissues and CaTiO_3-coated screws. X-ray imaging analysis showed in the CaTiO_3 coating group, there was a dense and tight binding between implants and the bone tissues; no radiation translucent zone was found surrounding the implants as well as no detachment of the coating and femoral condyle fracture. In contrast, uncoated screws exhibited a fibrous membrane layer, as evidenced by the detection of a radiation translucent zone between the implants and the bone tissues. Additionally, biomechanical testing revealed that the binding strength of CaTiO_3 coating with bone tissues was significantly higher than that of uncoated titanium screws, and was comparable to that of HA coating. The study demonstrated that CaTiO_3 coating in situ to titanium screws possesses great biocompatibility and osseointegration comparable to HA coating.展开更多
In an attempt to overcome the limitations of titanium in dental and orthopaedic clinical applications, a new method has been developed to prepare calcium carbonate coatings on sandblasted and acid-etched(SA) titanium ...In an attempt to overcome the limitations of titanium in dental and orthopaedic clinical applications, a new method has been developed to prepare calcium carbonate coatings on sandblasted and acid-etched(SA) titanium implants. The purpose of this study was to investigate the effect of calcium carbonate-SA(CC-SA) implants on osseointegration in vivo. The surfaces of SA and CC-SA implants were characterised for surface morphology and surface chemistry. Subsequently, these two kinds of implants were implanted in the femoral condyles of rabbits. The implants were retrieved and prepared for histological and histomorphometric evaluation 1, 2, 4, 8 and 12 weeks after implantation. Significantly higher values of bone-to-implant contact of the entire implant except the gap area(BIC_ALL) and the bone-to-implant contact of the gap area(BIC_GAP) were found in animals with the CC-SA implants than in those with the SA implants at 4 weeks. Higher values of total gap bone were found in those with the CC-SA implants than in those with the SA implants at 1, 2 and 4 weeks. In conclusion, the current findings demonstrate that the calcium carbonate coating can improve and accelerate the early ingrowth of bone and osseointegration at the early healing phase. This may reduce clinical healing times and thus improve implant success rates.展开更多
Objective: Research on enhancing early osseointegration of cementless implants to improve early fixation and reducing of risk of loosening. Methods: Thirty New Zealand rabbits were divided into two groups at random. B...Objective: Research on enhancing early osseointegration of cementless implants to improve early fixation and reducing of risk of loosening. Methods: Thirty New Zealand rabbits were divided into two groups at random. BMP combined with DBM 30 mg was inserted around the prosthesis in 15 rabbits as experimental group, the remaining rabbits were served as control group. After 4, 8, and 12 weeks, five rabbits were sacrificed in each group. The humerus with the implants were retrieved. Bone ingrowth was analyzed by none-decalcification bone ground section and biomechanical test. Results: At the end of 4 and 8 weeks the osseointegration rates of BMP group were higher than those of control(P < 0.05). The ultimate shear strength between BMP treated implantation and the control was the same as the results in osseointegration rates at 4, 8 weeks (P < 0.05). However, there was no difference between the treated and untreated group in the osseointegration rate and ultimate shear strength at 12 weeks(P > 0.05). Conclusion: BMP combination can enhance bone growth into gaps around cementless implants, especially in the early postoperative period.展开更多
Background:Treatment of methicillin-resistant Staphylococcus aureus(MRSA)biofilm infections in implant placement surgery is limited by the lack of antimicrobial activity of titanium(Ti)implants.There is a need to expl...Background:Treatment of methicillin-resistant Staphylococcus aureus(MRSA)biofilm infections in implant placement surgery is limited by the lack of antimicrobial activity of titanium(Ti)implants.There is a need to explore more effective approaches for the treatment of MRSA biofilm infections.Methods:Herein,an interfacial functionalization strategy is proposed by the integration of mesoporous polydopamine nanoparticles(PDA),nitric oxide(NO)release donor sodium nitroprusside(SNP)and osteogenic growth peptide(OGP)onto Ti implants,denoted as Ti-PDA@SNP-OGP.The physical and chemical properties of Ti-PDA@SNP-OGP were assessed by scanning electron microscopy,X-ray photoelectron spectroscope,water contact angle,photothermal property and NO release behavior.The synergistic antibacterial effect and elimination of the MRSA biofilms were evaluated by 2′,7′-dichlorofluorescein diacetate probe,1-N-phenylnaphthylamine assay,adenosine triphosphate intensity,O-nitrophenyl-β-D-galactopyranoside hydrolysis activity,bicinchoninic acid leakage.Fluorescence staining,assays for alkaline phosphatase activity,collagen secretion and extracellular matrix mineralization,quantitative real‑time reverse transcription‑polymerase chain reaction,and enzyme-linked immunosorbent assay(ELISA)were used to evaluate the inflammatory response and osteogenic ability in bone marrow stromal cells(MSCs),RAW264.7 cells and their co-culture system.Giemsa staining,ELISA,micro-CT,hematoxylin and eosin,Masson's trichrome and immunohistochemistry staining were used to evaluate the eradication of MRSA biofilms,inhibition of inflammatory response,and promotion of osseointegration of Ti-PDA@SNP-OGP in vivo.Results:Ti-PDA@SNP-OGP displayed a synergistic photothermal and NO-dependent antibacterial effect against MRSA following near-infrared light(NIR)irradiation,and effectively eliminated the formed MRSA biofilms by inducing reactive oxygen species(ROS)-mediated oxidative stress,destroying bacterial membrane integrity and causing leakage of intracellular components(P<0.01).In vitro experiments revealed that Ti-PDA@SNP-OGP not only facilitated osteogenic differentiation of MSCs,but also promoted the polarization of pro-inflammatory M1 macrophages to the anti-inflammatory M2-phenotype(P<0.05 or P<0.01).The favorable osteo-immune microenvironment further facilitated osteogenesis of MSCs and the anti-inflammation of RAW264.7 cells via multiple paracrine signaling pathways(P<0.01).In vivo evaluation confirmed the aforementioned results and revealed that Ti-PDA@SNP-OGP induced ameliorative osseointegration in an MRSA-infected femoral defect implantation model(P<0.01).Conclusions:Ti-PDA@SNP-OGP is a promising multi-functional material for the high-efficient treatment of MRSA infections in implant replacement surgeries.展开更多
Bone injury and implantation operation are often accompanied by microenvironment damage of bone tis-sue,which seriously affects the process of osseointegration of implants,especially for titanium(Ti)-based bioinert ma...Bone injury and implantation operation are often accompanied by microenvironment damage of bone tis-sue,which seriously affects the process of osseointegration of implants,especially for titanium(Ti)-based bioinert materials.Thus,repairing or improving the microenvironment of damaged bone tissue is of great significance for bone rescue,reconstruction,and regeneration,which is still a major medical challenge.Oxidative stress(OS)and oxygen(O_(2))deficiency are considered to be specific physiological signals of the bone-injury microenvironment.From the above background,a coating consisting of manganese dioxide(MnO_(2))nanoenzyme and strontium(Sr)ions was fabricated on the surface of the Ti implant via a one-step hydrothermal treatment.MnO_(2) nanoenzyme presented in the coating alleviated OS and O_(2) deficiency at the injury site by catalyzing the decomposition of abundant endogenous H_(2)O_(2) around the modified Ti implants into O_(2).In addition,Sr ions were released from the surface of the implant at a certain rate in a body-fluid environment,further promoting the adhesion,growth,and osteogenic differentiation of mesenchymal stem cells.More importantly,a Sprague Dawley rat femur model demonstrated that the modified Ti implant showed significant potential to accelerate bone tissue reconstruction in vivo.In sum-mary,the present system provides a new idea for the treatment of bone injury and the development of new orthopedic implants.展开更多
Objectives:Spinal fusion is a widely employed treatment of patients with degenerative disc disease,in which a cage is used to replace the disc for spinal fusion.But it often fails for insufficient mechanical strength ...Objectives:Spinal fusion is a widely employed treatment of patients with degenerative disc disease,in which a cage is used to replace the disc for spinal fusion.But it often fails for insufficient mechanical strength and poor osseointegration.Here,we designed a polyether-ether-ketone(PEEK)/tantalum(Ta)composite cage with a biomimetic gradient porous micro-structure,simultaneously enhancing mechanical properties and accelerating osseointegration in spinal fusion.Materials and methods:In the study,based on the mechanical performances of PEEK and osteogenic potential of Ta,and the three-dimensional(3D)structures of cuttlebone and vertebra,the cages were respectively 3D printed by pure PEEK,PEEK with 5 wt%Ta(PEEK/Ta-5),PEEK with 10 wt%Ta(PEEK/Ta-10)and PEEK with 15 wt%Ta(PEEK/Ta-15),then verified<i>in vitro</i>and in sheep cervical fusion model systematically.Results:Vertebral Gyroid structure PEEK/Ta-15 cage exhibited superior mechanical properties than Cuttlebone-like structure PEEK/Ta-15 cage,closer to the cervical vertebra.Furthermore,PEEK/Ta-15 cage with higher Ta microparticles in PEEK provided a biomimetic gradient porous micro-structure with higher surface energy,guiding cell biological behavior,promoting new bone penetration,and accelerating osseointegration<i>in vivo</i>.Conclusion:In conclusion,the study designed a biomimetic gradient porous cage with a micro-structure for enhancing mechanical properties,accelerating osseointegration and forming an anatomical lock in the fusion segment through composites,mechanical efficiency,surface extension,and pores.展开更多
In this study,different conditions of sandblasting on dental implant fixtures were investigated to achieve the best sandblasting conditions.18 different sandblasting conditions(Using 152 implant fixture samples)were e...In this study,different conditions of sandblasting on dental implant fixtures were investigated to achieve the best sandblasting conditions.18 different sandblasting conditions(Using 152 implant fixture samples)were examined,including parameters such as particle size,particle blasting pressure,and particle blasting angle.The surface treatment of the samples was performed using the SLA+Anodizing method.AFM testing was performed for each of the 18 different states,and the average surface roughness of each of these was compared with each other.Then,a bone layer was placed on the sample with the closest average surface roughness to the standard and the least amount of aluminum oxide on its surface among the 18 different states,to confirm the accuracy and quality of the desired surface roughness by examining the bone formation process and speed.The results showed that state No.4(sandblast particle size:75µm,spraying pressure of sandblast particles:4 bar,sandblast particle spraying angle:30 degrees),which was prepared using the SLA+Anodizing method and had a surface roughness of 1.989µm(The percentage of Al_(2)O_(3)on the surface=6%),had the best sandblasting conditions and showed 95%cell viability and accelerated the treatment and bone formation process for about a week.The simulation results,using Abaqus software,indicated that the stress distribution on the surface of the implant fixture in contact with the bone surface has increased by approximately 4.3%for state No.4.This will help prevent loosening of the dental implant fixture over time.展开更多
Three-dimensional-printed(3 D-P) titanium implants display many advantages, such as design flexibility,higher efficiency, the capability to easily construct complex or customized structures, etc., and is believed to p...Three-dimensional-printed(3 D-P) titanium implants display many advantages, such as design flexibility,higher efficiency, the capability to easily construct complex or customized structures, etc., and is believed to potentially replace traditional implants. However, the biological performance of the 3 D-P titanium surface has not been investigated systematically. Herein, we analyzed the surface characteristics of 3 D-P Ti6 Al4 V implants and evaluated the biological responses of bone marrow derived mesenchymal stromal cells(BMSCs) to the 3 D-P surface in vitro. Moreover, after implantation into the rat femoral condyle for3 and 6 weeks, the osseointegration performance was evaluated. The results showed the 3 D-P Ti6 Al4 V implant presented distinct fluctuant macroscale rough surface and relatively better hydrophilicity which enhanced the adhesion, proliferation, osteogenic differentiation and angiogenetic factor expression of BMSCs. Moreover, the in vivo osseointegration performance was also better than that of the control group at the early stage. The present study suggested the 3 D-P titanium alloy is a promising candidate to be used as implant material.展开更多
Additive manufacturing of porous, open-cellular metal or alloy implants, fabricated by laser or electron beam melting of a powder bed, is briefly reviewed in relation to optimizing biomechanical compatibility by assur...Additive manufacturing of porous, open-cellular metal or alloy implants, fabricated by laser or electron beam melting of a powder bed, is briefly reviewed in relation to optimizing biomechanical compatibility by assuring elastic(Young's) modulus matching of proximate bone, along with corresponding pore sizes assuring osseointegration and vasculature development and migration. In addition, associated, requisite compressive and fatigue strengths for such implants are described. Strategies for optimizing osteoblast(bone cell) development and osteoinduction as well as vascularization of tissue in 3 D scaffolds and tissue engineering constructs for bone repair are reviewed in relation to the biology of osteogenesis and neovascularization in bone, and the role of associated growth factors, bone morphogenic proteins, signaling molecules and the like. Prospects for infusing hydrogel/collagen matrices containing these cellular and protein components or surgically extracted intramedullary(bone marrow) concentrate/aspirate containing these biological and cell components into porous implants are discussed, as strategies for creating living implants, which over the long term would act as metal or alloy scaffolds.展开更多
As an implantable biomaterial,polyetherketoneketone(PEKK)exhibits good mechanical strength but it is biologically inert while tantalum(Ta)possesses outstanding osteogenic bioactivity but has a high density and elastic...As an implantable biomaterial,polyetherketoneketone(PEKK)exhibits good mechanical strength but it is biologically inert while tantalum(Ta)possesses outstanding osteogenic bioactivity but has a high density and elastic modulus.Also,silicon nitride(SN)has osteogenic and antibacterial activity.In this study,a microporous surface containing both SN and Ta microparticles on PEKK(STP)exhibiting excellent osteogenic and antibacterial activity was created by sulfonation.Compared with sulfonated PEKK(SPK)without microparticles,the surface properties(roughness,surface energy,hydrophilicity and protein adsorption)of STP significantly increased due to the SN and Ta particles presence on the microporous surface.In addition,STP also exhibited outstanding antibacterial activity,which inhibited bacterial growth in vitro and prevented bacterial infection in vivo because of the presence of SN particles.Moreover,the microporous surface of STP containing both SN and Ta particles remarkably induced response(e.g.,proliferation and differentiation)of rat bone mesenchymal stem(rBMS)cells in vitro.Furthermore,STP significantly improved new bone regeneration and osseointegration in vivo.Regarding the induction of cellular response in vitro and improvement of osseointegration in vivo,the microporous surface containing Ta was better than the surface with SN particles.In conclusion,STP with optimized surface properties activated cellular responses in vitro,enhanced osseointegration and prevented infection in vivo.Therefore,STP possessed the dual biofunctions of excellent osteogenic and antibacterial activity,showing great potential as a bone substitute.展开更多
Polyetherketoneketone(PEKK)exhibits admirable biocompatibility and mechanical performances but bioinert while tantalum(Ta)possesses excellent osteogenesis and osseointegration but high elastic modulus and density,and ...Polyetherketoneketone(PEKK)exhibits admirable biocompatibility and mechanical performances but bioinert while tantalum(Ta)possesses excellent osteogenesis and osseointegration but high elastic modulus and density,and processing is too difficult and expensive.In the present study,combining of the advantages of both PEKK and Ta,implantable composites of PEKK/Ta were fabricated by blending PEKK with Ta microparticles of 20 v%(PT20)and 40 v%(PT40)content.In comparison with PT20 and PEKK,the surface hydrophilicity,surface energy,roughness and proteins adsorption as well as mechanical performances of PT40 significantly increased because of the higher Ta particles content in PEKK.Furthermore,PT40 exhibited the mechanical performances(e.g.,compressive strength and modulus of elasticity)close to the cortical bone of human.Compared with PT20 and PEKK,PT40 with higher Ta content remarkably enhanced the responses(including adhesion,proliferation and osteogenic differentiation)of MC3T3-E1 cells in vitro.Moreover,PT40 markedly improved bone formation as well as osseointegration in vivo.In short,incorporation of Ta microparticles into PEKK created implantable composites with improved surface performances,which played key roles in stimulating cell responses/bone formation as well as promoting osseointegration.PT40 might have great potential for bear-loading bone substitute.展开更多
Osseointegration of implant provides a stable support for the prosthesis under functional loads.The timing of loading is a critical parameter that can govern the success of the osseointegration of implant.However,it i...Osseointegration of implant provides a stable support for the prosthesis under functional loads.The timing of loading is a critical parameter that can govern the success of the osseointegration of implant.However,it is not clear whether the early loading can affect the success of osseointegration,or whether the no-loading healing period can be shortened.This paper presents an animal study conducted to investigate how external loads influence the osseointegration at the initial stage of healing.Titanium implants were inserted into the goat tibia laterally,and different axial loadings were applied to the im-plants in 4 weeks after surgery.After the 2 weeks period of early loading,animals were sacrificed and the tibia bones with the implants were cut off from the bodies.Then mechanical test was employed to find out the differences in the pull-out force,and shear strength at the bone-implant interface between the non-loaded and the loaded implants.The implant-bone interfaces were analyzed by histomor-phometric method,SEM(scanning electron micrograph) and EDS(energy density spectrum).The re-sults indicated that the bone-implant interface did not well integrate 4 weeks after surgery,and the fi-brous tissue could be found at the interfaces of the specimens without loadings.While the results of loaded specimens with 10 N axial force showed that that parts of the interface were well integrated,indicating that the early mild loading may play a positive role in the process of the osseointegration.The results support that a certain range of external loading would influence the process of osseointe-gration,and appropriate mechanical loading can be applied to shorten the osseointegration period after surgery.展开更多
The purpose of this study was to analyze the effect of strontium-substituted hydroxyapatite (Sr-HA) on bone osseointegration of the implants using fluorescence microscopy. We allocated 20 implants to two groups: Sr-HA...The purpose of this study was to analyze the effect of strontium-substituted hydroxyapatite (Sr-HA) on bone osseointegration of the implants using fluorescence microscopy. We allocated 20 implants to two groups: Sr-HA group and HA group. Electrochemically deposited HA and Sr-HA coatings were applied onto the implants separately. All the implants were inserted into femur bone of rabbits. Oxytetracycline hydrochloride, alizarin-complexon, and calcein green were respectively administered 7, 28, and 46 d after the implantation. After eight weeks, femurs were retrieved and prepared for the fluorescence microscopy observation. We analyzed the bone mineral apposition rates (MARs), bone area ratios (BARs), and bone to implant contact (BIC) of the two groups. Fluorescence microscopic observation showed that all groups exhibited extensive early peri-implant bone formation. The MAR of the Sr-HA group was greater than that for pure HA from 7 to 28 d after implantation, but no significant difference was found at later stage. And the BIC showed difference at 7 and 28 d compared with pure HA. We concluded that Sr-HA coating can improve the bone osseointegration of the implant in the early stage compared with the HA coating.展开更多
Implant loosening remains a major clinical challenge for osteoporotic patients.This is because osteoclastic bone resorption rate is higher than osteoblastic bone formation rate in the case of osteoporosis,which result...Implant loosening remains a major clinical challenge for osteoporotic patients.This is because osteoclastic bone resorption rate is higher than osteoblastic bone formation rate in the case of osteoporosis,which results in poor bone repair.Strontium(Sr)has been widely accepted as an anti-osteoporosis element.In this study,we fabricated a series of apatite and Sr-substituted apatite coatings via electrochemical deposition under different acidic conditions.The results showed that Ca and Sr exhibited different mineralization behaviors.The main mineralization products for Ca were CaHPO4⋅2H2O and Ca3(PO4)2 with the structure changed from porous to spherical as the pH values increased.The main mineralization products for Sr were SrHPO4 and Sr5(PO4)3OH with the structure changed from flake to needle as the pH values increased.The in vitro experiment demonstrated that coatings fabricated at high pH condition with the presence of Sr were favorable to MSCs adhesion,spreading,proliferation,and osteogenic differentiation.In addition,Sr-substituted apatite coatings could evidently inhibit osteoclast differentiation and fusion.Moreover,the in vivo study indicated that nano-needle like Sr-substituted apatite coating could suppress osteoclastic activity,improve new bone formation,and enhance bone-implant integration.This study provided a new theoretical guidance for implant coating design and the fabricated Sr-substituted coating might have potential applications for osteoporotic patients.展开更多
Calcium phosphate-based materials(CaP)have been widely used as bone graft substitutes with a decent osseointegration.However,the mechanism whereby cells function and repair the bone defect in CaP micro-environment is ...Calcium phosphate-based materials(CaP)have been widely used as bone graft substitutes with a decent osseointegration.However,the mechanism whereby cells function and repair the bone defect in CaP micro-environment is still elusive.The aim of this study is to find the mechanism how osteoclast behaviors mediate bone healing with CaP scaffolds.Recent reports show that behaviors of osteoclast are closely related with osteogenesis,thus we make a hypothesis that active osteoclast behaviors induced by CaP facilitate bone healing.Here,we found a new mechanism that CaP can regulate osteoclast-mediated osseointegration.Calcium phosphate cement(CPC)is selected as a representative CaP.We demonstrate that the osteoclast-mediated osseointegration can be strongly modulated by the stimulation with CaP.An appropriate Ca/P ratio in CaP can effectively promote the RANKL-RANK binding and evoke more activated NF-κB signaling transduction,which results in vigorous osteoclast differentiation.We observe significant improvement of bone healing in vivo,owing to the active coupling effect of osteoclasts.What is more noteworthy is that the phosphate ions released from CaP can be a pivotal role regulating osteoclast activity by changing Ca/P ratio readily in materials.These studies suggest the potential of harnessing osteoclast-mediated osteogenesis in order to develop a materials-manipulated approach for improving osseointegration.展开更多
基金Scientific Research Project of Hainan Provincial Department of Education (No.Hnky2018ZD-7)。
文摘Dental implant is an effective method in the treatment of missing teeth.The process of osseointegration of implant teeth involves the coordinated operation of immune system and bone system.The interaction between cells is closely related to bone formation and repair.Exosomes are important intercellular communication molecules.They were originally found in the supernatant of sheep erythrocytes cultured in vitro.They are micro vesicles with a diameter of 40~150 nm.They exist in a variety of cells and body fluids.They enter the target cells by endocytosis and transport,affecting the expression of cell genes and changing the fate of cells.It has an important regulatory function in the microenvironment of implant bone binding.It plays a role in bone remodeling through small molecular RNA,specific proteins and other growth factors secreted by different cells.This article reviews the role of bone derived cellderived exosomes in bone remodeling and their function in implant osseointegration.
基金financially supported by China Postdoctoral Science Foundation [No.2016M592971]Logistics Department of the Chinese People’s Liberation Army [No.AKJ15J003]
文摘Objective To observe the effect of high positive acceleration(+Gz) environment on dental implant osseointegration in a rabbit model and to investigate its mechanism.Methods Forty-eight New Zealand white rabbits were randomly divided into 6 groups. The rabbit’s mandibular incisors were extracted and 1 implant was placed in each socket immediately. After 1 week of rest, the rabbits were exposed to a high +Gz environment, 3 times a week. The rabbits were sacrificed at 3 weeks(2 weeks +Gz exposure), 5 weeks(4 weeks +Gz exposure), and 12 weeks(4 weeks +Gz exposure and 7 weeks normal environment) after surgery, respectively. Specimens were harvested for micro-CT scanning, histological analysis, and real-time polymerase chain reaction examination.Results Compared with those in the control group, the mRNA expression levels of bone morphogenetic protein-2(BMP-2), osteopontin(OPN), and transforming growth factor-β1(TGF-β1)were significantly lower(P < 0.05), while the mRNA expression level of receptor activator of nuclear factor κB ligand(RANKL) and the RANKL/osteoprotegerin(OPG) ratio were significantly higher(P < 0.05)at 3 weeks;values of bone volume fraction, trabecular number, bone-implant contact(BIC), and TGF-β1 and OPG mRNA expression levels were significantly lower(P < 0.05), and the value of trabecular separation, RANKL mRNA expression level and RANKL/OPG ratio were significantly higher(P < 0.05) at 5 weeks;and the value of BIC was still significantly lower(P < 0.05) at 12 weeks in the experimental group.Conclusion Early exposure to the high +Gz environment after implant surgery might have an adverse effect on osseointegration, and its mechanism could be related to the inhibition of osteoblast activity and promotion of osteoclast activity.
基金funded by the National Natural Science Foundation of China(Nos.81801006,31870953,81901048,81620108006,81991505,81921002,81801023,and 82100963)Shanghai Rising-Star Program(21QA1405400)+1 种基金the National Key Research and Development Program of China(No.2016YFC1102900)Innovative Research Team of High-Level Local Universities in Shanghai(No.SSMU-ZDCX20180900)。
文摘Following dental implantation,the characteristic bacterial milieu of the oral cavity may lead to peri-implant inflammation,which can negatively impact osseointegration and cause implant failure.To improve soft tissue sealing around the implant,enhance osseointegration,and improve implant success rates,this paper proposes a composite multifunctional coating(PHG)prepared using gelatin and polydopamine/hydroxyapatite nanoparticles,investigates the effects of this novel coating on cell adhesion,proliferation,antibacterial activity,osteogenic differentiation,and evaluates its immune-related properties.The PHG coating was proved to have satisfactory hydrophilicity and wettability for cell attachment.Furthermore,it improved the expression of adhesion-related genes and proteins in human gingival fibroblasts,indicating its adhesion-promoting effect.Additionally,bone marrow mesenchymal stem cells exhibited strong osteogenic differentiation potential and mineralization on PHG-coated surfaces.Notably,the PHG coating exhibited antibacterial activity against Streptococcus mutans,as well as anti-inflammatory effects,potentially via the regulation of macrophages.Therefore,the proposed PHG coating may promote soft tissue sealing and bone bonding,providing a potential strategy for the surface modification of dental implants.
文摘In this work, we analysed 56 clinically failed and retrieved implants by means of scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and histological studies. The surface contamination was compared to that of unused control implants and with that of the same implants after cleaning in a basic medium. The surfaces of the unused implants presented considerable contamination. In particular, high levels of carbon were detected. The nature of this C was elucidated by XPS analysis of the lubricant used in the machining process. The same contamination was observed in the retrieved implants. Histological studies were carried out by means of light microscopy. Fibrosis and granulomatous lesions were detected in the tissues. XPS analysis indicated the presence of traces of other elements (Na, Ca, Zn, S, F, etc.) that were not related to impurities in cpTi. We examined a cleaning process in a basic medium that eliminates the organic components of the implant surfaces. The cleaned implants were implanted in the patients and the results were excellent. None of the implants failed in following 7 months.
基金financially supported by the Research and Development Fund for Applied Technology of Dalian(No.2014E14SF164)National Natural Science Foundation of China(No.51371042 and No.81171008)the Research Fund for the Doctoral Program of Higher Education of China(No.20130041110005)
文摘In our previous studies, a novel cortex-like Ti O2 coating was prepared on Ti surface through micro-arc oxidation(MAO) by using sodium tetraborate as electrolyte, and the effects of the coating on cell attachment were testified. This study aimed to investigate the effects of this cortex-like MAO coating on osseointegration. A sand-blasting and acid-etching(SLA) coating that has been widely used in clinical practice served as control. Topographical and chemical characterizations were conducted by scanning electron microscopy, energy dispersive X-ray spectrometer, X-ray diffraction, contact angle meter, and step profiler. Results showed that the cortex-like coating had microslots and nanopores and it was superhydrophilic, whereas the SLA surface was hydrophobic. The roughness of MAO was similar to that of SLA. The MAO and SLA implants were implanted into the femoral condyles of New Zealand rabbits to evaluate their in-vivo performance through micro-CT, histological analysis, and fluorescent labeling at the bone-implant interface four weeks after surgery. The micro-CT showed that the bone volume ratio and mean trabecular thickness were similar between MAO and SLA groups four weeks after implantation. Histological analysis and fluorescent labeling showed no significant differences in the bone-implant contact between the MAO and SLA surfaces. It was suggested that with micro/nanostructure and superhydrophilicity, the cortex-like MAO coating causes excellent osseointegration, holding a promise of an application to implant modification.
基金supported by the National Natural Science Foundation of China(Nos.81572150,81571939)the Natural Science Foundation of Hunan Province(No.2015JJ2187)the Wu Jie-Ping Medical Foundation of the Minister of Health of China(No.320675014118)
文摘This study aimed to examine the biocompatibility of calcium titanate(CaTiO_3) coating prepared by a simplified technique in an attempt to assess the potential of CaTiO_3 coating as an alternative to current implant coating materials. CaTiO_3-coated titanium screws were implanted with hydroxyapatite(HA)-coated or uncoated titanium screws into medial and lateral femoral condyles of 48 New Zealand white rabbits. Imaging, histomorphometric and biomechanical analyses were employed to evaluate the osseointegration and biocompatibility 12 weeks after the implantation. Histology and scanning electron microscopy revealed that bone tissues surrounding the screws coated with CaTiO_3 were fully regenerated and they were also well integrated with the screws. An interfacial fibrous membrane layer, which was found in the HA coating group, was not noticeable between the bone tissues and CaTiO_3-coated screws. X-ray imaging analysis showed in the CaTiO_3 coating group, there was a dense and tight binding between implants and the bone tissues; no radiation translucent zone was found surrounding the implants as well as no detachment of the coating and femoral condyle fracture. In contrast, uncoated screws exhibited a fibrous membrane layer, as evidenced by the detection of a radiation translucent zone between the implants and the bone tissues. Additionally, biomechanical testing revealed that the binding strength of CaTiO_3 coating with bone tissues was significantly higher than that of uncoated titanium screws, and was comparable to that of HA coating. The study demonstrated that CaTiO_3 coating in situ to titanium screws possesses great biocompatibility and osseointegration comparable to HA coating.
基金funded by the National Natural Science Foundation of China(nos 81200812 and 81371170)the Foundation of Health and the family planning commission of Hubei province(no.WJ2015MB276)
文摘In an attempt to overcome the limitations of titanium in dental and orthopaedic clinical applications, a new method has been developed to prepare calcium carbonate coatings on sandblasted and acid-etched(SA) titanium implants. The purpose of this study was to investigate the effect of calcium carbonate-SA(CC-SA) implants on osseointegration in vivo. The surfaces of SA and CC-SA implants were characterised for surface morphology and surface chemistry. Subsequently, these two kinds of implants were implanted in the femoral condyles of rabbits. The implants were retrieved and prepared for histological and histomorphometric evaluation 1, 2, 4, 8 and 12 weeks after implantation. Significantly higher values of bone-to-implant contact of the entire implant except the gap area(BIC_ALL) and the bone-to-implant contact of the gap area(BIC_GAP) were found in animals with the CC-SA implants than in those with the SA implants at 4 weeks. Higher values of total gap bone were found in those with the CC-SA implants than in those with the SA implants at 1, 2 and 4 weeks. In conclusion, the current findings demonstrate that the calcium carbonate coating can improve and accelerate the early ingrowth of bone and osseointegration at the early healing phase. This may reduce clinical healing times and thus improve implant success rates.
文摘Objective: Research on enhancing early osseointegration of cementless implants to improve early fixation and reducing of risk of loosening. Methods: Thirty New Zealand rabbits were divided into two groups at random. BMP combined with DBM 30 mg was inserted around the prosthesis in 15 rabbits as experimental group, the remaining rabbits were served as control group. After 4, 8, and 12 weeks, five rabbits were sacrificed in each group. The humerus with the implants were retrieved. Bone ingrowth was analyzed by none-decalcification bone ground section and biomechanical test. Results: At the end of 4 and 8 weeks the osseointegration rates of BMP group were higher than those of control(P < 0.05). The ultimate shear strength between BMP treated implantation and the control was the same as the results in osseointegration rates at 4, 8 weeks (P < 0.05). However, there was no difference between the treated and untreated group in the osseointegration rate and ultimate shear strength at 12 weeks(P > 0.05). Conclusion: BMP combination can enhance bone growth into gaps around cementless implants, especially in the early postoperative period.
基金financially supported by the National Natural Science Foundation of China(82101069,82102537,82160411,82002278)the Natural Science Foundation of Chongqing Science and Technology Commission(CSTC2021JCYJ-MSXMX0170,CSTB2022BSXM-JCX0039)+2 种基金the First Affiliated Hospital of Chongqing Medical University Cultivating Fund(PYJJ2021-02)the Beijing Municipal Science&Technology Commission(Z221100007422130)the Youth Incubation Program of Medical Science and Technology of PLA(21QNPY116).
文摘Background:Treatment of methicillin-resistant Staphylococcus aureus(MRSA)biofilm infections in implant placement surgery is limited by the lack of antimicrobial activity of titanium(Ti)implants.There is a need to explore more effective approaches for the treatment of MRSA biofilm infections.Methods:Herein,an interfacial functionalization strategy is proposed by the integration of mesoporous polydopamine nanoparticles(PDA),nitric oxide(NO)release donor sodium nitroprusside(SNP)and osteogenic growth peptide(OGP)onto Ti implants,denoted as Ti-PDA@SNP-OGP.The physical and chemical properties of Ti-PDA@SNP-OGP were assessed by scanning electron microscopy,X-ray photoelectron spectroscope,water contact angle,photothermal property and NO release behavior.The synergistic antibacterial effect and elimination of the MRSA biofilms were evaluated by 2′,7′-dichlorofluorescein diacetate probe,1-N-phenylnaphthylamine assay,adenosine triphosphate intensity,O-nitrophenyl-β-D-galactopyranoside hydrolysis activity,bicinchoninic acid leakage.Fluorescence staining,assays for alkaline phosphatase activity,collagen secretion and extracellular matrix mineralization,quantitative real‑time reverse transcription‑polymerase chain reaction,and enzyme-linked immunosorbent assay(ELISA)were used to evaluate the inflammatory response and osteogenic ability in bone marrow stromal cells(MSCs),RAW264.7 cells and their co-culture system.Giemsa staining,ELISA,micro-CT,hematoxylin and eosin,Masson's trichrome and immunohistochemistry staining were used to evaluate the eradication of MRSA biofilms,inhibition of inflammatory response,and promotion of osseointegration of Ti-PDA@SNP-OGP in vivo.Results:Ti-PDA@SNP-OGP displayed a synergistic photothermal and NO-dependent antibacterial effect against MRSA following near-infrared light(NIR)irradiation,and effectively eliminated the formed MRSA biofilms by inducing reactive oxygen species(ROS)-mediated oxidative stress,destroying bacterial membrane integrity and causing leakage of intracellular components(P<0.01).In vitro experiments revealed that Ti-PDA@SNP-OGP not only facilitated osteogenic differentiation of MSCs,but also promoted the polarization of pro-inflammatory M1 macrophages to the anti-inflammatory M2-phenotype(P<0.05 or P<0.01).The favorable osteo-immune microenvironment further facilitated osteogenesis of MSCs and the anti-inflammation of RAW264.7 cells via multiple paracrine signaling pathways(P<0.01).In vivo evaluation confirmed the aforementioned results and revealed that Ti-PDA@SNP-OGP induced ameliorative osseointegration in an MRSA-infected femoral defect implantation model(P<0.01).Conclusions:Ti-PDA@SNP-OGP is a promising multi-functional material for the high-efficient treatment of MRSA infections in implant replacement surgeries.
基金financially supported by the National Natu-ral Science Foundation of China (Nos.32171327,21734002,and 51825302)the Natural Science Foundation of Chongqing (No.cstc2021jcyj-cxttX0002).
文摘Bone injury and implantation operation are often accompanied by microenvironment damage of bone tis-sue,which seriously affects the process of osseointegration of implants,especially for titanium(Ti)-based bioinert materials.Thus,repairing or improving the microenvironment of damaged bone tissue is of great significance for bone rescue,reconstruction,and regeneration,which is still a major medical challenge.Oxidative stress(OS)and oxygen(O_(2))deficiency are considered to be specific physiological signals of the bone-injury microenvironment.From the above background,a coating consisting of manganese dioxide(MnO_(2))nanoenzyme and strontium(Sr)ions was fabricated on the surface of the Ti implant via a one-step hydrothermal treatment.MnO_(2) nanoenzyme presented in the coating alleviated OS and O_(2) deficiency at the injury site by catalyzing the decomposition of abundant endogenous H_(2)O_(2) around the modified Ti implants into O_(2).In addition,Sr ions were released from the surface of the implant at a certain rate in a body-fluid environment,further promoting the adhesion,growth,and osteogenic differentiation of mesenchymal stem cells.More importantly,a Sprague Dawley rat femur model demonstrated that the modified Ti implant showed significant potential to accelerate bone tissue reconstruction in vivo.In sum-mary,the present system provides a new idea for the treatment of bone injury and the development of new orthopedic implants.
文摘Objectives:Spinal fusion is a widely employed treatment of patients with degenerative disc disease,in which a cage is used to replace the disc for spinal fusion.But it often fails for insufficient mechanical strength and poor osseointegration.Here,we designed a polyether-ether-ketone(PEEK)/tantalum(Ta)composite cage with a biomimetic gradient porous micro-structure,simultaneously enhancing mechanical properties and accelerating osseointegration in spinal fusion.Materials and methods:In the study,based on the mechanical performances of PEEK and osteogenic potential of Ta,and the three-dimensional(3D)structures of cuttlebone and vertebra,the cages were respectively 3D printed by pure PEEK,PEEK with 5 wt%Ta(PEEK/Ta-5),PEEK with 10 wt%Ta(PEEK/Ta-10)and PEEK with 15 wt%Ta(PEEK/Ta-15),then verified<i>in vitro</i>and in sheep cervical fusion model systematically.Results:Vertebral Gyroid structure PEEK/Ta-15 cage exhibited superior mechanical properties than Cuttlebone-like structure PEEK/Ta-15 cage,closer to the cervical vertebra.Furthermore,PEEK/Ta-15 cage with higher Ta microparticles in PEEK provided a biomimetic gradient porous micro-structure with higher surface energy,guiding cell biological behavior,promoting new bone penetration,and accelerating osseointegration<i>in vivo</i>.Conclusion:In conclusion,the study designed a biomimetic gradient porous cage with a micro-structure for enhancing mechanical properties,accelerating osseointegration and forming an anatomical lock in the fusion segment through composites,mechanical efficiency,surface extension,and pores.
文摘In this study,different conditions of sandblasting on dental implant fixtures were investigated to achieve the best sandblasting conditions.18 different sandblasting conditions(Using 152 implant fixture samples)were examined,including parameters such as particle size,particle blasting pressure,and particle blasting angle.The surface treatment of the samples was performed using the SLA+Anodizing method.AFM testing was performed for each of the 18 different states,and the average surface roughness of each of these was compared with each other.Then,a bone layer was placed on the sample with the closest average surface roughness to the standard and the least amount of aluminum oxide on its surface among the 18 different states,to confirm the accuracy and quality of the desired surface roughness by examining the bone formation process and speed.The results showed that state No.4(sandblast particle size:75µm,spraying pressure of sandblast particles:4 bar,sandblast particle spraying angle:30 degrees),which was prepared using the SLA+Anodizing method and had a surface roughness of 1.989µm(The percentage of Al_(2)O_(3)on the surface=6%),had the best sandblasting conditions and showed 95%cell viability and accelerated the treatment and bone formation process for about a week.The simulation results,using Abaqus software,indicated that the stress distribution on the surface of the implant fixture in contact with the bone surface has increased by approximately 4.3%for state No.4.This will help prevent loosening of the dental implant fixture over time.
基金support of the National Key R&D Program of China (No. 2017YFB1104100)National Natural Science Foundation of China (No. 81371129, 81670973)+1 种基金the Science and Technology Commission of Shanghai (No. 17410710500, 16DZ0503800, 17510710800)the Fund of Shanghai Municipal Commission of Health and Family Planning (No. 201540369)
文摘Three-dimensional-printed(3 D-P) titanium implants display many advantages, such as design flexibility,higher efficiency, the capability to easily construct complex or customized structures, etc., and is believed to potentially replace traditional implants. However, the biological performance of the 3 D-P titanium surface has not been investigated systematically. Herein, we analyzed the surface characteristics of 3 D-P Ti6 Al4 V implants and evaluated the biological responses of bone marrow derived mesenchymal stromal cells(BMSCs) to the 3 D-P surface in vitro. Moreover, after implantation into the rat femoral condyle for3 and 6 weeks, the osseointegration performance was evaluated. The results showed the 3 D-P Ti6 Al4 V implant presented distinct fluctuant macroscale rough surface and relatively better hydrophilicity which enhanced the adhesion, proliferation, osteogenic differentiation and angiogenetic factor expression of BMSCs. Moreover, the in vivo osseointegration performance was also better than that of the control group at the early stage. The present study suggested the 3 D-P titanium alloy is a promising candidate to be used as implant material.
文摘Additive manufacturing of porous, open-cellular metal or alloy implants, fabricated by laser or electron beam melting of a powder bed, is briefly reviewed in relation to optimizing biomechanical compatibility by assuring elastic(Young's) modulus matching of proximate bone, along with corresponding pore sizes assuring osseointegration and vasculature development and migration. In addition, associated, requisite compressive and fatigue strengths for such implants are described. Strategies for optimizing osteoblast(bone cell) development and osteoinduction as well as vascularization of tissue in 3 D scaffolds and tissue engineering constructs for bone repair are reviewed in relation to the biology of osteogenesis and neovascularization in bone, and the role of associated growth factors, bone morphogenic proteins, signaling molecules and the like. Prospects for infusing hydrogel/collagen matrices containing these cellular and protein components or surgically extracted intramedullary(bone marrow) concentrate/aspirate containing these biological and cell components into porous implants are discussed, as strategies for creating living implants, which over the long term would act as metal or alloy scaffolds.
基金The grants were supported by the National Natural Science Foundation of China(81771990,81801845 and 81200815)Key Medical Program of Science and Technology Development of Shanghai(19441906100 and 17441902000)Shenzhen Fundamental Research Program(JCYJ20190807160811355).
文摘As an implantable biomaterial,polyetherketoneketone(PEKK)exhibits good mechanical strength but it is biologically inert while tantalum(Ta)possesses outstanding osteogenic bioactivity but has a high density and elastic modulus.Also,silicon nitride(SN)has osteogenic and antibacterial activity.In this study,a microporous surface containing both SN and Ta microparticles on PEKK(STP)exhibiting excellent osteogenic and antibacterial activity was created by sulfonation.Compared with sulfonated PEKK(SPK)without microparticles,the surface properties(roughness,surface energy,hydrophilicity and protein adsorption)of STP significantly increased due to the SN and Ta particles presence on the microporous surface.In addition,STP also exhibited outstanding antibacterial activity,which inhibited bacterial growth in vitro and prevented bacterial infection in vivo because of the presence of SN particles.Moreover,the microporous surface of STP containing both SN and Ta particles remarkably induced response(e.g.,proliferation and differentiation)of rat bone mesenchymal stem(rBMS)cells in vitro.Furthermore,STP significantly improved new bone regeneration and osseointegration in vivo.Regarding the induction of cellular response in vitro and improvement of osseointegration in vivo,the microporous surface containing Ta was better than the surface with SN particles.In conclusion,STP with optimized surface properties activated cellular responses in vitro,enhanced osseointegration and prevented infection in vivo.Therefore,STP possessed the dual biofunctions of excellent osteogenic and antibacterial activity,showing great potential as a bone substitute.
基金Key Medical Program of Science and Technology Development of Shanghai(17441902000 and 19441906100)the National Natural Science Foundation of China(81771990 and 81801845)Shenzhen Fundamental Research Program(JCYJ20190807160811355).
文摘Polyetherketoneketone(PEKK)exhibits admirable biocompatibility and mechanical performances but bioinert while tantalum(Ta)possesses excellent osteogenesis and osseointegration but high elastic modulus and density,and processing is too difficult and expensive.In the present study,combining of the advantages of both PEKK and Ta,implantable composites of PEKK/Ta were fabricated by blending PEKK with Ta microparticles of 20 v%(PT20)and 40 v%(PT40)content.In comparison with PT20 and PEKK,the surface hydrophilicity,surface energy,roughness and proteins adsorption as well as mechanical performances of PT40 significantly increased because of the higher Ta particles content in PEKK.Furthermore,PT40 exhibited the mechanical performances(e.g.,compressive strength and modulus of elasticity)close to the cortical bone of human.Compared with PT20 and PEKK,PT40 with higher Ta content remarkably enhanced the responses(including adhesion,proliferation and osteogenic differentiation)of MC3T3-E1 cells in vitro.Moreover,PT40 markedly improved bone formation as well as osseointegration in vivo.In short,incorporation of Ta microparticles into PEKK created implantable composites with improved surface performances,which played key roles in stimulating cell responses/bone formation as well as promoting osseointegration.PT40 might have great potential for bear-loading bone substitute.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 30370376,10529202 and 10672015)
文摘Osseointegration of implant provides a stable support for the prosthesis under functional loads.The timing of loading is a critical parameter that can govern the success of the osseointegration of implant.However,it is not clear whether the early loading can affect the success of osseointegration,or whether the no-loading healing period can be shortened.This paper presents an animal study conducted to investigate how external loads influence the osseointegration at the initial stage of healing.Titanium implants were inserted into the goat tibia laterally,and different axial loadings were applied to the im-plants in 4 weeks after surgery.After the 2 weeks period of early loading,animals were sacrificed and the tibia bones with the implants were cut off from the bodies.Then mechanical test was employed to find out the differences in the pull-out force,and shear strength at the bone-implant interface between the non-loaded and the loaded implants.The implant-bone interfaces were analyzed by histomor-phometric method,SEM(scanning electron micrograph) and EDS(energy density spectrum).The re-sults indicated that the bone-implant interface did not well integrate 4 weeks after surgery,and the fi-brous tissue could be found at the interfaces of the specimens without loadings.While the results of loaded specimens with 10 N axial force showed that that parts of the interface were well integrated,indicating that the early mild loading may play a positive role in the process of the osseointegration.The results support that a certain range of external loading would influence the process of osseointe-gration,and appropriate mechanical loading can be applied to shorten the osseointegration period after surgery.
基金Project supported by the Excellent Youth Science Foundation of Zhejiang Provincial Natural Science Foundation of China(No.R2110374)the Provincial Department Co-building Foundation of Health Bureau of Zhejiang Province,China(No.WKJ2011-2-009)
文摘The purpose of this study was to analyze the effect of strontium-substituted hydroxyapatite (Sr-HA) on bone osseointegration of the implants using fluorescence microscopy. We allocated 20 implants to two groups: Sr-HA group and HA group. Electrochemically deposited HA and Sr-HA coatings were applied onto the implants separately. All the implants were inserted into femur bone of rabbits. Oxytetracycline hydrochloride, alizarin-complexon, and calcein green were respectively administered 7, 28, and 46 d after the implantation. After eight weeks, femurs were retrieved and prepared for the fluorescence microscopy observation. We analyzed the bone mineral apposition rates (MARs), bone area ratios (BARs), and bone to implant contact (BIC) of the two groups. Fluorescence microscopic observation showed that all groups exhibited extensive early peri-implant bone formation. The MAR of the Sr-HA group was greater than that for pure HA from 7 to 28 d after implantation, but no significant difference was found at later stage. And the BIC showed difference at 7 and 28 d compared with pure HA. We concluded that Sr-HA coating can improve the bone osseointegration of the implant in the early stage compared with the HA coating.
基金the National Natural Science Foundation of China for Innovative Research Groups(Grant No.51621002)China Postdoctoral Science Foundation(Grant No.2018M640350)+1 种基金National Natural Science Foundation of China(Grant No.51871163)Shanghai International S&T Cooperation Project(Grant No.18520710100).
文摘Implant loosening remains a major clinical challenge for osteoporotic patients.This is because osteoclastic bone resorption rate is higher than osteoblastic bone formation rate in the case of osteoporosis,which results in poor bone repair.Strontium(Sr)has been widely accepted as an anti-osteoporosis element.In this study,we fabricated a series of apatite and Sr-substituted apatite coatings via electrochemical deposition under different acidic conditions.The results showed that Ca and Sr exhibited different mineralization behaviors.The main mineralization products for Ca were CaHPO4⋅2H2O and Ca3(PO4)2 with the structure changed from porous to spherical as the pH values increased.The main mineralization products for Sr were SrHPO4 and Sr5(PO4)3OH with the structure changed from flake to needle as the pH values increased.The in vitro experiment demonstrated that coatings fabricated at high pH condition with the presence of Sr were favorable to MSCs adhesion,spreading,proliferation,and osteogenic differentiation.In addition,Sr-substituted apatite coatings could evidently inhibit osteoclast differentiation and fusion.Moreover,the in vivo study indicated that nano-needle like Sr-substituted apatite coating could suppress osteoclastic activity,improve new bone formation,and enhance bone-implant integration.This study provided a new theoretical guidance for implant coating design and the fabricated Sr-substituted coating might have potential applications for osteoporotic patients.
基金This research was supported by National Natural Science Foundation of China for Innovative Research Groups(No.51621002)the National Natural Science Foundation of China(No.31870953)This study was also supported by the 111 Project(B14018).
文摘Calcium phosphate-based materials(CaP)have been widely used as bone graft substitutes with a decent osseointegration.However,the mechanism whereby cells function and repair the bone defect in CaP micro-environment is still elusive.The aim of this study is to find the mechanism how osteoclast behaviors mediate bone healing with CaP scaffolds.Recent reports show that behaviors of osteoclast are closely related with osteogenesis,thus we make a hypothesis that active osteoclast behaviors induced by CaP facilitate bone healing.Here,we found a new mechanism that CaP can regulate osteoclast-mediated osseointegration.Calcium phosphate cement(CPC)is selected as a representative CaP.We demonstrate that the osteoclast-mediated osseointegration can be strongly modulated by the stimulation with CaP.An appropriate Ca/P ratio in CaP can effectively promote the RANKL-RANK binding and evoke more activated NF-κB signaling transduction,which results in vigorous osteoclast differentiation.We observe significant improvement of bone healing in vivo,owing to the active coupling effect of osteoclasts.What is more noteworthy is that the phosphate ions released from CaP can be a pivotal role regulating osteoclast activity by changing Ca/P ratio readily in materials.These studies suggest the potential of harnessing osteoclast-mediated osteogenesis in order to develop a materials-manipulated approach for improving osseointegration.
