The poor surface conditions and osseointegration capacity of 3D printed Ti6Al4V implants(3DPT)significantly influence their performance as orthopedic and dental implants.In this work,we creatively introduce a one-step...The poor surface conditions and osseointegration capacity of 3D printed Ti6Al4V implants(3DPT)significantly influence their performance as orthopedic and dental implants.In this work,we creatively introduce a one-step femtosecond laser treatment to improve the surface conditions and osteointegration.The surface characterization,mechanical properties,corrosion resistance,and biological responses were investigated.These results found that femtosecond laser eliminated defects like embedded powders and superficial cracks while forming the nano cones-like structures surface on 3DPT,leading to enhanced osseointegration,anti-corrosion,and anti-fatigue performance.Molecular dynamics simulations revealed the ablation removal mechanism and the formation of nano cone-like structures.These findings were further supported by the in vivo studies,showing that the FS-treated implants had superior bone-implant contact and osseointegration.Hence,the one-step femtosecond laser method is regarded as a promising surface modification method for improving the functional performance of Ti-based orthopedic implants.展开更多
Polyetheretherketone(PEEK)is a desirable candidate to replace conventional metal implants owing to its excellent mechanical properties.However,the intrinsic bioinertness of PEEK results in inferior or delayed osseoint...Polyetheretherketone(PEEK)is a desirable candidate to replace conventional metal implants owing to its excellent mechanical properties.However,the intrinsic bioinertness of PEEK results in inferior or delayed osseointegration,which limits its further clinical application.To address these challenges,one leading strategy is to construct a biofunctionalized surface on PEEK that provides a coordinated osteoblastosteoclast interactions microenvironment.Herein,alendronate(ALN),a common bone absorption inhibitor,was loaded in biomedical inorganic/organic microspheres,consisting of bioactive inorganic nanohydroxyapatite core,and chitosan(CS)shell.Polydopamine(PDA)modification was employed to ensure the adherence of the microspheres to the PEEK surface.The delivery of ALN and Ca^(2+)from these microspheres simultaneously suppressed osteoclastogenesis and promoted osteogenesis,resulting in a coordinated cascade of osteoblast-osteoclast interactions crucial for the per-implant osseointegration.In vitro experiments demonstrated that the PEEK surface exhibited satisfactory biocompatibility and enhanced the proliferation and osteogenic differentiation of rat bone mesenchymal stem cells while inhibiting the osteoclast differentiation.Moreover,the in vivo rat femoral drilling model demonstrated superior osseointegration three months after implantation.By considering the bone remodeling processes,this study proposes a novel biofunctionalized PEEK surface that regulates the activities of both osteoblasts and osteoclasts to promote osseointegration.展开更多
The remodeling of macrophages mediated by biomaterials is an important step in osseointegration.The biointerfacial characteristics shaped by implants and the bioenergetic state derived from macrophages are considered ...The remodeling of macrophages mediated by biomaterials is an important step in osseointegration.The biointerfacial characteristics shaped by implants and the bioenergetic state derived from macrophages are considered the key to macrophage reprogramming.In this study,the integrated Ti/Zn composites with optimized morphology and bioactive phase were prepared by friction stir processing,which could meet the multi-biofunctional requirements in the application of narrow-diameter implants.The severe plastic deformation and the hindrance of Zn particles to grain growth promote grain refinement,resulting in enhanced mechanical properties.The cell interfacial adhesion mediated by the grain boundary collaborated the energy metabolism reprogramming induced by the released Zn ion,promoting jointly anti-inflammatory cascade in macrophages and favorable osteogenesis in bone marrow mesenchymal stem cells(BMSCs).This study provides a new simultaneous approach of morphology and composition modification for titanium implants,and reveals the important role of grain size and bioactive element in the reversion of macrophage fate as well.展开更多
The pore structure of porous scaffolds plays a crucial role in bone repair.The prevalent bone implant structure in clinical practice is the traditional cubic structure.However,the traditional cubic structure exhibits ...The pore structure of porous scaffolds plays a crucial role in bone repair.The prevalent bone implant structure in clinical practice is the traditional cubic structure.However,the traditional cubic structure exhibits sharp edges and junctions that are not conducive to cell adhesion or growth.In this study,a double gyroid(DG)Ti6Al4V scaffold based on a triply periodic minimal surface(TPMS)structure was devised,and the osseointegration performance of DG structural scaffolds with varying porosities was investigated.Compression tests revealed that the elastic modulus and compressive strength of DG structural scaffolds were sufficient for orthopedic implants.In vitro cellular experiments demonstrated that the DG structure significantly enhanced cell proliferation,vascularization,and osteogenic differentiation compared to the cubic structure.The DG structure with 55%porosity exhibited the most favorable outcomes.In vivo experiments in rabbits further demonstrated that DG scaffolds could promote neovascularization and bone regeneration and maturation;those with 55%porosity performed best.Comparing the surface area,specific surface area per unit volume,and internal flow distribution characteristics of gyroid and DG structure scaffolds,the latter are more conducive to cell adhesion and growth within scaffolds.This study underscored the potential of DG scaffolds based on the TPMS structure in optimizing the pore structure design of titanium scaffolds,inducing angiogenesis,and advancing the clinical application of titanium scaffolds for repairing bone defects.展开更多
Objective A high sodium(HS)diet is believed to affect bone metabolism processes.Clarifying its impact on osseointegration of titanium(Ti)implants holds significant implications for postoperative dietary management of ...Objective A high sodium(HS)diet is believed to affect bone metabolism processes.Clarifying its impact on osseointegration of titanium(Ti)implants holds significant implications for postoperative dietary management of implanted patients.Methods This investigation probed the impact of sodium ions(Na^(+))on neovascularization and osteogenesis around Ti implants in vivo,utilizing micro-computed tomography,hematoxylin and eosin staining,and immunohistochemical analyses.Concurrently,in vitro experiments assessed the effects of varied Na^(+)concentrations and exposure durations on human umbilical vein endothelial cells(HUVECs)and MC3T3-E1 cells.Results In vivo,increased dietary sodium(0.8%-6.0%)led to a substantial decline in CD34 positive HUVECs and new bone formation around Ti implants,alongside an increase in inflammatory cells.In vitro,an increase in Na^(+)concentration(140-150 mmol/L)adversely affected the proliferation,angiogenesis,and migration of HUVECs,especially with prolonged exposure.While MC3T3-E1 cells initially exhibited less susceptibility to high Na^(+)concentrations compared to HUVECs during short-term exposure,prolonged exposure to a HS environment progressively diminished their proliferation,differentiation,and osteogenic capabilities.Conclusion These findings suggest that HS diet had a negative effect on the early osseointegration of Ti implants by interfering with the process of postoperative vascularized bone regeneration.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
Polyetheretherketone(PEEK)has been recognized for its immense potential in hard tissue repair applications due to its mechanical properties resembling those of natural bones.However,the inherent bioinertness of pristi...Polyetheretherketone(PEEK)has been recognized for its immense potential in hard tissue repair applications due to its mechanical properties resembling those of natural bones.However,the inherent bioinertness of pristine PEEK results in insufficient osseointegration.Moreover,implant-associated infection(IAI)has become a serious threat in orthopedic surgery.These risks usually lead to implant loosening,delayed healing,and even the failure of implantation,hampering many clinical applications of PEEK.In this study,we present a facile strategy to endow PEEK implants with enhanced osseointegration and pH-responsive antibacterial activity.Briefly,pristine PEEK was first treated with mixed acids to obtain a porous structure(referred to as SNPEEK),and then the metal-phenolic networks(MPN)coating was prepared using layer-by-layer(LbL)assembly consisting of Sr^(2+) and tannin acid(TA)(referred to as ST coating).The results demonstrated that the dual-functional PEEK displayed enhanced antibacterial activity in pH-responsive manner.At pH 7.4,the antibacterial ratios were 71.72%and 66.79%against Staphylococcus aureus(MSSA,ATCC 25,923)and methicillin-resistant Staphylococcus aureus(MRSA,ATCC BAA-40),respectively.Remarkably,at pH 5.5,the antibacterial activities significantly increased,resulting in killing ratios of 99.98%and 100%,respectively.Furthermore,the dual-functional PEEK promoted osteogenic differentiation of pre-osteoblasts(MC3T3-E1)and migration of human umbilical vascular endothelial cells(HUVECs).In addition,the dual-functional PEEK demonstrated effective anti-infection ability and desirable new bone formation ability in vivo compared to both pristine PEEK and SNPEEK implants.Overall,this study provides a promising strategy to endow PEEK implants with effective osseointegration and anti-infective ability,representing a prospective solution to address current clinical challenges associated with PEEK implants.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
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
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
The porous titanium with a channel-like pore structure fabricated by infiltration casting followed by selectively dissolving the precursor woven three dimensional(3D)structure technique was comprehensively investigate...The porous titanium with a channel-like pore structure fabricated by infiltration casting followed by selectively dissolving the precursor woven three dimensional(3D)structure technique was comprehensively investigated by means of mechanical tests,in vitro and in vivo evaluation.Such porous structure exhibited superiority in compressive,tensile strength and osseointegration.At 40%porosity,the average compressive and tensile strength reached about 145MPa and 85 MPa,which was superior to that of other porous titanium,e.g.,Selective Laser Melting or powder sintered ones,and was comparable to that of the human cortical bone.Without any bioactive surface treatment,this porous titanium exhibited good cell adhesion,rapid cell proliferation and excellent osseointegration.Based on the study,the 0.4mm pore size resulted in the most rapid cell proliferation and the maximal BV/TV ratio and trabecular bone number of the new bone that ingrew into the porous titanium.To balance the excellent osseointegration and adequate mechanical properties,the optimal structural parameters were 0.4mmpore size with 40%porosity.This porous titanium is very promising for orthopedic applications where compressive and tensile load-bearing is extremely important.展开更多
A double acid corrosion and subsequent hydrothermal treatment were used to fabricate a micro–nano-structured Ti substrates(Ti–M–N).Afterward,the mesoporous polydopamine(MPDA)nanoparticles as photothermal agent were...A double acid corrosion and subsequent hydrothermal treatment were used to fabricate a micro–nano-structured Ti substrates(Ti–M–N).Afterward,the mesoporous polydopamine(MPDA)nanoparticles as photothermal agent were prepared and immobilized on the surface of Ti–M–N samples,in order to obtain Ti–M–NMPDA sample.Unique micro–nanostructure properties and the photothermal effect of the modified Ti implant caused physical stress on the bacteria and the bacterial membrane damage,and eventually led to bacteria death.More importantly,based on excellent bioactivity and cytocompatibility of mussel-inspired materials,MPDA promoted adhesion,proliferation and osteogenic differentiation of mesenchymal stem cells in vitro.Furthermore,animal experiments in vivo further confirmed that the modified Ti implants could enhance osseointegration.展开更多
The advent of three-dimensional （3-D） printed technique provides great possibility in the fabrication of customized porous titanium （Ti） implant. However, the bioinert property of the printed Ti poses an out- stan...The advent of three-dimensional （3-D） printed technique provides great possibility in the fabrication of customized porous titanium （Ti） implant. However, the bioinert property of the printed Ti poses an out- standing problem. Hybrid micro-arc oxidation and hydrothermal （MAO-HT） treatment on porous metals is able to produce multi-scaled hierarchical orthopedic implant, showing great potential for surface mod- ification of 3-D printed implant. In this study, cylindrical porous Ti6Al4V （Ti64） scaffolds with pore size of 640 lure, porosity of ？3% were 3-D printed by electron beam melting process, and their surfaces were left untreated or treated by a combined MAO-HT procedure. In vitro bioactivity was tested by immer- sion in simulated body fluid for different time points. Then, 12 scaffolds in each group were implanted into the femoral condyles of New Zealand rabbit for 8 weeks. Osseointegration was evaluated by qual- itative and quantitative histological analysis, and the bone ingrowth features were probed by sequential fluorescent labeling at 3 and 6 weeks post-surgery, Following the MAO-HT treatment, the porous Ti64 scaffold was endowed with multi-scaled micro/nano-topographies and high amounts of CaP on its surface. The treated scaffold exhibited drastically enhanced apatite forming ability compared with the un- treated one. In vivo test revealed significantly that a higher amount of bone ingrowth and bone implant contact at the treated scaffold. The 2 types of scaffolds had different patterns of bone ingrowth; the treated scaffold exhibited a pattern of contact osteogenesis, by which bone formed directly on the treated implant surface, whereas bone formed distal to the implant surface of the untreated scaffold. MAO-HT treat- ment can significantly enhance the in vitro apatite-inducing ability and in vivo osseointegration capacity of 3-D porous Ti64 scaffold and may provide as a viable approach for the fabrication of bioactive 3-D printed porous implant for orthopedic applications.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
This study aimed to examine the biocompatibility of calcium titanate(CaTiO3) coating prepared by a simplified technique in an attempt to assess the potential of CaTiO3coating as an alternative to current implant coati...This study aimed to examine the biocompatibility of calcium titanate(CaTiO3) coating prepared by a simplified technique in an attempt to assess the potential of CaTiO3coating as an alternative to current implant coating materials. CaTiO3-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 CaTiO3were 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 CaTiO3-coated screws. X-ray imaging analysis showed in the CaTiO3coating 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 CaTiO3coating with bone tissues was significantly higher than that of uncoated titanium screws, and was comparable to that of HA coating. The study demonstrated that CaTiO3coating in situ to titanium screws possesses great biocompatibility and osseointegration comparable to HA coating.展开更多
Magnesium （Mg） has been widely accepted as osteoconductive biomaterial, but osseointegration of Mg device at different implantation sites is still unclear. In the present study, high-purity magnesium （HP Mg） pins ...Magnesium （Mg） has been widely accepted as osteoconductive biomaterial, but osseointegration of Mg device at different implantation sites is still unclear. In the present study, high-purity magnesium （HP Mg） pins were implanted into femoral shaft and condyle of New Zealand rabbits concurrently. 2, 8, 12 and 16 weeks after surgery, rabbit femurs were harvested for micro-computed tomography （micro-CT） scanning and subsequent histological examinations. HP Mg pins were retrieved for scanning electron microscope and energy dispersive spectrum （SEM/EDS） analyses. HP Mg pins at both implantation sites performed stable corrosion with mineral deposition and bone incorporation on surface. However, difference in distribution of contact osteogenesis centers and biological properties of peri-implant bone tissues was detected between femoral shaft and femoral condyle. In femoral condyle, contact osteogenesis centers originated from both periosteum and cancellous bones and the whole HP Mg pin was encapsuled in trabecular bone at 16 weeks. Meanwhile, bone volume to total bone volume （BV/TV） and bone mineral density （BMD） of peri-implant bone tissues were above those of normal bone tissues. In femoral shaft, contact osteogenesis centers were only from periosteum and direct bone contact was confined in cortical bone, while BV/TV and BMD kept lower than normal. Furthermore, new formation of peri-implant bone tissues was more active in femoral condyle than in femoral shaft at 16 weeks. Therefore, although HP Mg performed good biocompatibility and corrosion behavior in vivo, its bioadaption of osseointegration at different implantations sites should be taken into consideration. Bone metaphysic was suitable for Mg devices where peri-implant bone tissues regenerated rapidly and the biological properties were close to normal bone tissues.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 we...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
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） titani...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 healine phase. This may reduce clinical healinE times and thus improve implant success rates.展开更多
基金supported by the National Natural Science Foundation of China(No.U21A2055),Natural Science Foundation of Tianjin of China(No.21JCQNJC01280)Tianjin Key R&D Program Beijing-Tianjin-Hebei Collaborative Innovation Project(No.22YFXTHZ00120).
文摘The poor surface conditions and osseointegration capacity of 3D printed Ti6Al4V implants(3DPT)significantly influence their performance as orthopedic and dental implants.In this work,we creatively introduce a one-step femtosecond laser treatment to improve the surface conditions and osteointegration.The surface characterization,mechanical properties,corrosion resistance,and biological responses were investigated.These results found that femtosecond laser eliminated defects like embedded powders and superficial cracks while forming the nano cones-like structures surface on 3DPT,leading to enhanced osseointegration,anti-corrosion,and anti-fatigue performance.Molecular dynamics simulations revealed the ablation removal mechanism and the formation of nano cone-like structures.These findings were further supported by the in vivo studies,showing that the FS-treated implants had superior bone-implant contact and osseointegration.Hence,the one-step femtosecond laser method is regarded as a promising surface modification method for improving the functional performance of Ti-based orthopedic implants.
基金the funding support from the Tianjin Medical University“Clinical Talent Training 123 Climbing Plan”the Youth Fund of Tianjin Medical University Second Hospital(No.2022ydey06)。
文摘Polyetheretherketone(PEEK)is a desirable candidate to replace conventional metal implants owing to its excellent mechanical properties.However,the intrinsic bioinertness of PEEK results in inferior or delayed osseointegration,which limits its further clinical application.To address these challenges,one leading strategy is to construct a biofunctionalized surface on PEEK that provides a coordinated osteoblastosteoclast interactions microenvironment.Herein,alendronate(ALN),a common bone absorption inhibitor,was loaded in biomedical inorganic/organic microspheres,consisting of bioactive inorganic nanohydroxyapatite core,and chitosan(CS)shell.Polydopamine(PDA)modification was employed to ensure the adherence of the microspheres to the PEEK surface.The delivery of ALN and Ca^(2+)from these microspheres simultaneously suppressed osteoclastogenesis and promoted osteogenesis,resulting in a coordinated cascade of osteoblast-osteoclast interactions crucial for the per-implant osseointegration.In vitro experiments demonstrated that the PEEK surface exhibited satisfactory biocompatibility and enhanced the proliferation and osteogenic differentiation of rat bone mesenchymal stem cells while inhibiting the osteoclast differentiation.Moreover,the in vivo rat femoral drilling model demonstrated superior osseointegration three months after implantation.By considering the bone remodeling processes,this study proposes a novel biofunctionalized PEEK surface that regulates the activities of both osteoblasts and osteoclasts to promote osseointegration.
基金the National Natural Science Foundation of China(Nos.31971246&52274387)the Fundamental Research Funds for the Central Universities(No.YG2023QNA21)the Shanghai Science and Technology Commission(No.20S31900100)for their financial and project support.
文摘The remodeling of macrophages mediated by biomaterials is an important step in osseointegration.The biointerfacial characteristics shaped by implants and the bioenergetic state derived from macrophages are considered the key to macrophage reprogramming.In this study,the integrated Ti/Zn composites with optimized morphology and bioactive phase were prepared by friction stir processing,which could meet the multi-biofunctional requirements in the application of narrow-diameter implants.The severe plastic deformation and the hindrance of Zn particles to grain growth promote grain refinement,resulting in enhanced mechanical properties.The cell interfacial adhesion mediated by the grain boundary collaborated the energy metabolism reprogramming induced by the released Zn ion,promoting jointly anti-inflammatory cascade in macrophages and favorable osteogenesis in bone marrow mesenchymal stem cells(BMSCs).This study provides a new simultaneous approach of morphology and composition modification for titanium implants,and reveals the important role of grain size and bioactive element in the reversion of macrophage fate as well.
基金supported bythe National Natural Science Foundation of China(Nos.U23A20523,82272504,and 82072456)the Department of Science and Technology of Jilin Province,China(Nos.20210101439JC,20210101321JC,20220204119YY,202201ZYTS131,202201ZYTS129,20230204114YY,YDZJ202201ZYTS505,and YDZJ202301ZYTS076)+4 种基金the Special Program for Science and Technology Personnel of Changchun(No.ZKICKJJ2023015)the Key Training Plan for Outstanding Youth of Jilin University(No.419070623036)the Research Fund of the First Hospital of Jilin University(No.2021-zl-01)the Graduate Innovation Fund of Jilin University(No.2024CX125)the Foun-dation of National Center for Translational Medicine(Shanghai)SHU Branch,China(No.SUITM-202405).
文摘The pore structure of porous scaffolds plays a crucial role in bone repair.The prevalent bone implant structure in clinical practice is the traditional cubic structure.However,the traditional cubic structure exhibits sharp edges and junctions that are not conducive to cell adhesion or growth.In this study,a double gyroid(DG)Ti6Al4V scaffold based on a triply periodic minimal surface(TPMS)structure was devised,and the osseointegration performance of DG structural scaffolds with varying porosities was investigated.Compression tests revealed that the elastic modulus and compressive strength of DG structural scaffolds were sufficient for orthopedic implants.In vitro cellular experiments demonstrated that the DG structure significantly enhanced cell proliferation,vascularization,and osteogenic differentiation compared to the cubic structure.The DG structure with 55%porosity exhibited the most favorable outcomes.In vivo experiments in rabbits further demonstrated that DG scaffolds could promote neovascularization and bone regeneration and maturation;those with 55%porosity performed best.Comparing the surface area,specific surface area per unit volume,and internal flow distribution characteristics of gyroid and DG structure scaffolds,the latter are more conducive to cell adhesion and growth within scaffolds.This study underscored the potential of DG scaffolds based on the TPMS structure in optimizing the pore structure design of titanium scaffolds,inducing angiogenesis,and advancing the clinical application of titanium scaffolds for repairing bone defects.
基金funded by the Wenzhou Public Welfare Science and Technology Project(Y2020118)Zhejiang Provincial Science and Technology Project for Public Welfare(LQ23H140001)Wenzhou Medical University Basic Scientific Research Operating Expenses(KYYW202230).
文摘Objective A high sodium(HS)diet is believed to affect bone metabolism processes.Clarifying its impact on osseointegration of titanium(Ti)implants holds significant implications for postoperative dietary management of implanted patients.Methods This investigation probed the impact of sodium ions(Na^(+))on neovascularization and osteogenesis around Ti implants in vivo,utilizing micro-computed tomography,hematoxylin and eosin staining,and immunohistochemical analyses.Concurrently,in vitro experiments assessed the effects of varied Na^(+)concentrations and exposure durations on human umbilical vein endothelial cells(HUVECs)and MC3T3-E1 cells.Results In vivo,increased dietary sodium(0.8%-6.0%)led to a substantial decline in CD34 positive HUVECs and new bone formation around Ti implants,alongside an increase in inflammatory cells.In vitro,an increase in Na^(+)concentration(140-150 mmol/L)adversely affected the proliferation,angiogenesis,and migration of HUVECs,especially with prolonged exposure.While MC3T3-E1 cells initially exhibited less susceptibility to high Na^(+)concentrations compared to HUVECs during short-term exposure,prolonged exposure to a HS environment progressively diminished their proliferation,differentiation,and osteogenic capabilities.Conclusion These findings suggest that HS diet had a negative effect on the early osseointegration of Ti implants by interfering with the process of postoperative vascularized bone regeneration.
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supported by the National Natu-ral Science Foundation of China(No.52073230)the Shaanxi Provincial Science Fund for Distinguished Young Scholars(No.2023-JC-JQ-32).
文摘Polyetheretherketone(PEEK)has been recognized for its immense potential in hard tissue repair applications due to its mechanical properties resembling those of natural bones.However,the inherent bioinertness of pristine PEEK results in insufficient osseointegration.Moreover,implant-associated infection(IAI)has become a serious threat in orthopedic surgery.These risks usually lead to implant loosening,delayed healing,and even the failure of implantation,hampering many clinical applications of PEEK.In this study,we present a facile strategy to endow PEEK implants with enhanced osseointegration and pH-responsive antibacterial activity.Briefly,pristine PEEK was first treated with mixed acids to obtain a porous structure(referred to as SNPEEK),and then the metal-phenolic networks(MPN)coating was prepared using layer-by-layer(LbL)assembly consisting of Sr^(2+) and tannin acid(TA)(referred to as ST coating).The results demonstrated that the dual-functional PEEK displayed enhanced antibacterial activity in pH-responsive manner.At pH 7.4,the antibacterial ratios were 71.72%and 66.79%against Staphylococcus aureus(MSSA,ATCC 25,923)and methicillin-resistant Staphylococcus aureus(MRSA,ATCC BAA-40),respectively.Remarkably,at pH 5.5,the antibacterial activities significantly increased,resulting in killing ratios of 99.98%and 100%,respectively.Furthermore,the dual-functional PEEK promoted osteogenic differentiation of pre-osteoblasts(MC3T3-E1)and migration of human umbilical vascular endothelial cells(HUVECs).In addition,the dual-functional PEEK demonstrated effective anti-infection ability and desirable new bone formation ability in vivo compared to both pristine PEEK and SNPEEK implants.Overall,this study provides a promising strategy to endow PEEK implants with effective osseointegration and anti-infective ability,representing a prospective solution to address current clinical challenges associated with PEEK implants.
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.
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This work was supported financially by the National Natural Science Foundation of China(Nos.U1704147 and 81772309).
文摘The porous titanium with a channel-like pore structure fabricated by infiltration casting followed by selectively dissolving the precursor woven three dimensional(3D)structure technique was comprehensively investigated by means of mechanical tests,in vitro and in vivo evaluation.Such porous structure exhibited superiority in compressive,tensile strength and osseointegration.At 40%porosity,the average compressive and tensile strength reached about 145MPa and 85 MPa,which was superior to that of other porous titanium,e.g.,Selective Laser Melting or powder sintered ones,and was comparable to that of the human cortical bone.Without any bioactive surface treatment,this porous titanium exhibited good cell adhesion,rapid cell proliferation and excellent osseointegration.Based on the study,the 0.4mm pore size resulted in the most rapid cell proliferation and the maximal BV/TV ratio and trabecular bone number of the new bone that ingrew into the porous titanium.To balance the excellent osseointegration and adequate mechanical properties,the optimal structural parameters were 0.4mmpore size with 40%porosity.This porous titanium is very promising for orthopedic applications where compressive and tensile load-bearing is extremely important.
基金This work was financially supported by the State Key Project of Research and Development(Nos.2016YFC1100300 and 2017YFB0702603)the National Natural Science Foundation of China(Nos.51825302,21734002 and 51673032).The Analytical and Testing Center of Chongqing University is greatly acknowledged for the help with the characterization of materials.
文摘A double acid corrosion and subsequent hydrothermal treatment were used to fabricate a micro–nano-structured Ti substrates(Ti–M–N).Afterward,the mesoporous polydopamine(MPDA)nanoparticles as photothermal agent were prepared and immobilized on the surface of Ti–M–N samples,in order to obtain Ti–M–NMPDA sample.Unique micro–nanostructure properties and the photothermal effect of the modified Ti implant caused physical stress on the bacteria and the bacterial membrane damage,and eventually led to bacteria death.More importantly,based on excellent bioactivity and cytocompatibility of mussel-inspired materials,MPDA promoted adhesion,proliferation and osteogenic differentiation of mesenchymal stem cells in vitro.Furthermore,animal experiments in vivo further confirmed that the modified Ti implants could enhance osseointegration.
基金the Beijing AKEC Medical Co.,LtdMedical Research Center of Peking University Third Hospitalsupported by the Project of Scientific and Technical Plan of Beijing(Nos.Z121100005312005 and Z141100002814008)
文摘The advent of three-dimensional （3-D） printed technique provides great possibility in the fabrication of customized porous titanium （Ti） implant. However, the bioinert property of the printed Ti poses an out- standing problem. Hybrid micro-arc oxidation and hydrothermal （MAO-HT） treatment on porous metals is able to produce multi-scaled hierarchical orthopedic implant, showing great potential for surface mod- ification of 3-D printed implant. In this study, cylindrical porous Ti6Al4V （Ti64） scaffolds with pore size of 640 lure, porosity of ？3% were 3-D printed by electron beam melting process, and their surfaces were left untreated or treated by a combined MAO-HT procedure. In vitro bioactivity was tested by immer- sion in simulated body fluid for different time points. Then, 12 scaffolds in each group were implanted into the femoral condyles of New Zealand rabbit for 8 weeks. Osseointegration was evaluated by qual- itative and quantitative histological analysis, and the bone ingrowth features were probed by sequential fluorescent labeling at 3 and 6 weeks post-surgery, Following the MAO-HT treatment, the porous Ti64 scaffold was endowed with multi-scaled micro/nano-topographies and high amounts of CaP on its surface. The treated scaffold exhibited drastically enhanced apatite forming ability compared with the un- treated one. In vivo test revealed significantly that a higher amount of bone ingrowth and bone implant contact at the treated scaffold. The 2 types of scaffolds had different patterns of bone ingrowth; the treated scaffold exhibited a pattern of contact osteogenesis, by which bone formed directly on the treated implant surface, whereas bone formed distal to the implant surface of the untreated scaffold. MAO-HT treat- ment can significantly enhance the in vitro apatite-inducing ability and in vivo osseointegration capacity of 3-D porous Ti64 scaffold and may provide as a viable approach for the fabrication of bioactive 3-D printed porous implant for orthopedic applications.
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.
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(CaTiO3) coating prepared by a simplified technique in an attempt to assess the potential of CaTiO3coating as an alternative to current implant coating materials. CaTiO3-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 CaTiO3were 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 CaTiO3-coated screws. X-ray imaging analysis showed in the CaTiO3coating 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 CaTiO3coating with bone tissues was significantly higher than that of uncoated titanium screws, and was comparable to that of HA coating. The study demonstrated that CaTiO3coating in situ to titanium screws possesses great biocompatibility and osseointegration comparable to HA coating.
基金supported by the National Natural Science Foundation of China(Nos.51271117 and 81371935)the Biomedical Program of Science and Technology Innovation Project supported by Shanghai(Nos.14441901800 and 14441901802)
文摘Magnesium （Mg） has been widely accepted as osteoconductive biomaterial, but osseointegration of Mg device at different implantation sites is still unclear. In the present study, high-purity magnesium （HP Mg） pins were implanted into femoral shaft and condyle of New Zealand rabbits concurrently. 2, 8, 12 and 16 weeks after surgery, rabbit femurs were harvested for micro-computed tomography （micro-CT） scanning and subsequent histological examinations. HP Mg pins were retrieved for scanning electron microscope and energy dispersive spectrum （SEM/EDS） analyses. HP Mg pins at both implantation sites performed stable corrosion with mineral deposition and bone incorporation on surface. However, difference in distribution of contact osteogenesis centers and biological properties of peri-implant bone tissues was detected between femoral shaft and femoral condyle. In femoral condyle, contact osteogenesis centers originated from both periosteum and cancellous bones and the whole HP Mg pin was encapsuled in trabecular bone at 16 weeks. Meanwhile, bone volume to total bone volume （BV/TV） and bone mineral density （BMD） of peri-implant bone tissues were above those of normal bone tissues. In femoral shaft, contact osteogenesis centers were only from periosteum and direct bone contact was confined in cortical bone, while BV/TV and BMD kept lower than normal. Furthermore, new formation of peri-implant bone tissues was more active in femoral condyle than in femoral shaft at 16 weeks. Therefore, although HP Mg performed good biocompatibility and corrosion behavior in vivo, its bioadaption of osseointegration at different implantations sites should be taken into consideration. Bone metaphysic was suitable for Mg devices where peri-implant bone tissues regenerated rapidly and the biological properties were close to normal bone tissues.
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 healine phase. This may reduce clinical healinE times and thus improve implant success rates.
