To improve the corrosion resistance of biodegradable Mg alloys,WE43 alloys were implanted with Fe,Ti,Zn and Zr ions at the same implantation dose.The surface morphology,valence state of elements,nano-hardness(NH),elas...To improve the corrosion resistance of biodegradable Mg alloys,WE43 alloys were implanted with Fe,Ti,Zn and Zr ions at the same implantation dose.The surface morphology,valence state of elements,nano-hardness(NH),elastic modulus(EM),degradation rate and in vitro cell experiments of the modified WE43 alloys were systematically studied.A modified layer composed of Mg,MgO,the implanted elements and their oxides was formed on the modified alloys.Since high-speed metal ions caused severe surface lattice damage,the surface hardness of the substrate considerable increased.Electrochemical tests demonstrated a substantial enhancement in the corrosion resistance of the modified alloys via the implantation of Ti and Zr ions,resulting in a reduction of the corrosion current density to 88.1±9.9 and 15.6±11.4μA cm^(−2),respectively,compared with the implantation of Fe and Zn ions.Biocompatibility tests showed that the implantation of Fe,Ti,Zn and Zr ions enhanced the anticoagulant and hemolytic resistance of the WE43 alloy.All surface-modified samples showed negligible cytotoxicity(0-1)at 12.5%extract concentration.Moreover,the alloys implanted with Fe,Ti and Zn ions significantly promoted proliferation of human umbilical vein endothelial cells(HUVEC)compared with the unmodified alloy.The results demonstrate that Ti ion implantation is the best choice for WE43 alloy modification to achieve outstanding corrosion resistance and biocompatibility.展开更多
The possible application of magnesium(Mg)in glaucoma surgical treatment has been investigated in our previous work.In this paper,the degradation behavior and biocompatibility of Mg coated with hydroxyapatite(HA)and di...The possible application of magnesium(Mg)in glaucoma surgical treatment has been investigated in our previous work.In this paper,the degradation behavior and biocompatibility of Mg coated with hydroxyapatite(HA)and dicalcium phosphate dihydrate(DCPD)in eye environment were evaluated,and uncoated Mg was used for comparison.It was found that uniform corrosion occurred macroscopically to the coated Mg samples in sodium lactate ringer’s injection(SLRI)as well as in the rabbit eyes.In micro-scale,the corrosion was characterized by local cracking and pitting primarily.Mg and calcium(Ca)were incorporated into the surface corrosion products and a multi-layer structure was formed.Compared to other samples,HA-coated Mg slowed down dramatically the alkalinity of the solution and the ion release of the sample,and exhibited the lowest corrosion rate in SLRI,which was about 0.22 mm/a.In terms of biocompatibility,fibroblasts demonstrated high viability in the HA-coated and DCPD-coated Mg groups(p<0.05)in vitro.In vivo,HA-coated Mg was found to show lower inflammatory response and fibrosis than the other groups did,as indicated by hematoxylin-eosin and immunofluorescence staining.During the degrading process of HA-coated Mg in the rabbits’eyes,no inflammation was found in the anterior chamber,lens,and vitreous body.HA-coated Mg was fully biodegraded fifteen weeks post-operation,and the scleral drainage channel(SDC)was formed without obvious scarring.It is concluded that HA-coated Mg implantation is a promising adjunctive procedure to improve the success rate of trabeculectomy.Statement of significance:Magnesium(Mg)has shown to be a potential biomaterial for ophthalmic implants in our previous work.However,inflammatory response resulted from the low corrosion resistance of Mg is a major concern.It is shown here that Mg coated with different calcium phosphates can improve these properties in varying degrees and keep the scleral drainage channel unobstructed and unscarred.Based on our in vitro and in vivo studies,HA-coated Mg exhibited a better degradation behavior and excellent biocompatibility.The scleral drainage channel still exists and aqueous humor flows out smoothly after the full degradation of the implant.It is concluded that HA-coated Mg is a promising biomaterial to increase the therapeutic efficiency of trabeculectomy for glaucoma.展开更多
Although the degradability and biosafety of magnesium alloys make them advantageous for biological applications,medical implants made of magnesium alloys often fail prematurely due to corrosion.Therefore,improving the...Although the degradability and biosafety of magnesium alloys make them advantageous for biological applications,medical implants made of magnesium alloys often fail prematurely due to corrosion.Therefore,improving the corrosion resistance of magnesium alloys has become an urgent problem in the alloy design process.In this study,we designed and prepared Mg-xZn-0.5Y-0.5Zr(x=1,2,and 3,wt%)alloys in a hot extruded state and analyzed their surface structure through scanning electron microscopy,energy dispersion spectrometry,and X-ray diffraction.It was found that increasing the Zn content refined the recrystallized grains in the alloy.Particularly in Mg-3Zn-0.5Y-0.5Zr,the I phase became finer,forming both granular and nanoscale needle-like particles.Surface characterization after the immersion experiment showed that the corrosion product layer was mainly composed of Mg(OH)_(2),Zn(OH)_(2),CaCO_(3),and hy-droxyapatite.The degradation rate of ZW305K was the lowest,measured as 4.1 and 6.0 mm·a^(-1) with the hydrogen precipitation method and weight loss method respectively.Electrochemical experiments further explained the corrosion circuit model of the alloy in solution and confirmed the earlier results.The maximum polarization resistance of ZW305K was 874.5Ω·cm^(2),and the lowest corrosion current density was 0.104 mA·cm^(-2).As a biomedical alloy,it must exhibit good biocompatibility,so the alloy was also tested through cytotoxicity,cell adhesion,and staining experiments.The cell viability of each group after 48 h was greater than 80%,showing that the addition of zinc enhances the alloy’s biocompatibility.In summary,the prepared alloys have the potential to be used as biodegradable implant materials.展开更多
Ti-Mo-O alloys were used to analyze the effect of Mo and O contents on the mechanical compatibility and biocompatibility.The bending modulus,bending yield strength and springback ratio of the alloys were evaluated by ...Ti-Mo-O alloys were used to analyze the effect of Mo and O contents on the mechanical compatibility and biocompatibility.The bending modulus,bending yield strength and springback ratio of the alloys were evaluated by using three-point bending tests and bending load-unloading tests.The biocompatibility was investigated by the adhesion,proliferation and the alkaline phosphatase(ALP)activity of mouse osteoblast-like cells(MC3T3-E1).The results showed that the bending modulus and bending yield strength first were increased and then decreased with the increase in Mo content,while the springback ratio exhibited an opposite trend to the bending modulus.With the increase in O content,the bending modulus remained almost constant,while the bending yield strength was increased.The springback ratio exhibited a similar trend to the bending yield strength.The in vitro biological experiments showed that the Ti-Mo-O alloys had excellent biocompatibility due to the formed stable oxide films on their surface.With the increase in O and Mo contents,the TiO_(2)-MoO_(2)oxide film became denser.Combining with mechanical compatibility and biocompatibility,the Ti-15Mo-0.2O and Ti-15Mo-0.3O alloys were more suitable for the biomedical application of spinal fixation device.展开更多
In this study,the effect of annealing on the microstructure and following corrosion and biological properties of Mg-1.0Ca-0.5Zn-0.1Y-0.03Mn(at.%)alloy prepared by rapid solidified powder metallurgy was investigated.Th...In this study,the effect of annealing on the microstructure and following corrosion and biological properties of Mg-1.0Ca-0.5Zn-0.1Y-0.03Mn(at.%)alloy prepared by rapid solidified powder metallurgy was investigated.The annealing at 300℃ for 2 h did not change the grain size significantly;however,a slight growth of Mg_(2)Ca precipitates was observed.When the annealing temperature increased up to 400℃ for 2 h,full recrystallization of the alloy occurred;the grains and precipitates grew noticeably.Those changes were responsible for decreasing the corrosion and the tribocorrosion resistance of the alloy.Due to lowered resistance to the corrosion medium,the cell viability was also reduced.Although MG63 cells on the annealed specimens developed filopodia,cell-to-cell communication was not observed.展开更多
Corrosion-resistant and biocompatible films were fabricated on AZ91D Mg alloy substrates by varying their roughness levels using met-allographic preparation and subsequent hydrothermal procedures.The coated films comp...Corrosion-resistant and biocompatible films were fabricated on AZ91D Mg alloy substrates by varying their roughness levels using met-allographic preparation and subsequent hydrothermal procedures.The coated films comprised a mixed structure of Mg(OH)_(2)and Mg-Al layered double hydroxides(LDH)and exhibited excellent compactness.Coating film thickness increased with decreasing surface roughness.Corrosion resistance was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy.Metallographic pretreat-ment influenced the chemical activity of the Mg alloy surface and helped modulate the dissolution rate of the Mg_(17)Al_(12)phase during the hydrothermal procedure.With decreasing roughness of the Mg substrate,the Al^(3+)concentration gradually increased,accelerating the in-situ formation of the Mg(OH)_(2)/LDH composite coating and improving its crystallinity.A thick and dense Mg(OH)_(2)/LDH coating was synthesized on the Mg substrate with the least roughness,substantially improving the corrosion resistance of the AZ91D alloy.The lowest corrosion current density((5.73±2.75)×10^(−8)A·cm^(−2))was achieved,which was approximately three orders of magnitude less than that of bare AZ91D.Moreover,the coating demonstrated biocompatibility with no evident cytotoxicity,cellular damage,and hemolytic phenomena.This study provides an effective method for preparing coatings on Mg alloy surfaces with excellent corrosion resistance and biocompatibility.展开更多
Developing high-performance aqueous Zn-ion batteries from sustainable biomass becomes increasingly vital for large-scale energy storage in the foreseeable future.Therefore,γ-MnO_(2) uniformly loaded on N-doped carbon...Developing high-performance aqueous Zn-ion batteries from sustainable biomass becomes increasingly vital for large-scale energy storage in the foreseeable future.Therefore,γ-MnO_(2) uniformly loaded on N-doped carbon derived from grapefruit peel is successfully fabricated in this work,and particularly the composite cathode with carbon carrier quality percentage of 20 wt%delivers the specific capacity of 391.2 mAh g^(−1)at 0.1 A g^(−1),outstanding cyclic stability of 92.17%after 3000 cycles at 5 A g^(−1),and remarkable energy density of 553.12 Wh kg^(−1) together with superior coulombic efficiency of~100%.Additionally,the cathodic biosafety is further explored specifically through in vitro cell toxicity experiments,which verifies its tremendous potential in the application of clinical medicine.Besides,Zinc ion energy storage mechanism of the cathode is mainly discussed from the aspects of Jahn–Teller effect and Mn domains distribution combined with theoretical analysis and experimental data.Thus,a novel perspective of the conversion from biomass waste to biocompatible Mn-based cathode is successfully developed.展开更多
The repair and regeneration of bone defects are highly challenging orthopedic problems.Recently,Mg-based implants have gained popularity due to their unique biodegradation and elastic modulus similar to that of human ...The repair and regeneration of bone defects are highly challenging orthopedic problems.Recently,Mg-based implants have gained popularity due to their unique biodegradation and elastic modulus similar to that of human bone.The aim of our study is to develop a magnesium alloy with a controllable degradation that can closely match bone tissue to help injuries heal in vivo and avoid cytotoxicity caused by a sudden increase in ion concentration.In this study,we prepared and modified Mg-3Zn,Mg-3Zn-1Y,and Mg-2Zn-1Mn by hot extrusion,and used Mg-2.5Y-2.5Nd was as a control.We then investigated the effect of additions of Y and Mn on alloys'properties.Our results show that Mn and Y can improve not only compression strength but also corrosion resistance.The alloy Mg-2Zn-1Mn demonstrated good cytocompatibility in vitro,and for this reason we selected it for implantation in vivo.The degraded Mg-2Zn-1Mn implanted a bone defect area did not cause obvious rejection and inflammatory reaction,and the degradation products left no signs of damage to the heart,liver,kidney,or brain.Furthermore,we find that Mg-2Zn-1Mn can promote an osteoinductive response in vivo and the formation of bone regeneration.展开更多
This study proposes a novel strategy for the design of a new family of metastable Zr alloys.These al-loys offer improved mechanical properties for implants,particularly in applications where conventional stainless ste...This study proposes a novel strategy for the design of a new family of metastable Zr alloys.These al-loys offer improved mechanical properties for implants,particularly in applications where conventional stainless steels and Co-Cr alloys are currently used but lack suitability.The design approach is based on the controlled twinning-induced plasticity(TWIP)effect,significantly enhancing the ductility and strain-hardenability of the Zr alloys.In order to draw a“blueprint”for the compositional design of biomedical T WIP(Bio-T WIP)Zr alloys-using only non-toxic elements,the study combines D-electron phase stability calculations(specifically bond order(Bo)and mean d-orbital energy(Md))with a systematic experimental screening of active deformation mechanisms within the Zr-Nb-Sn alloy system.This research aids in ac-curately identifying the TWIP line,which signifies the mechanism shift between TWIP and classic slip as the primary deformation mechanism.To demonstrate the efficacy of the TWIP mechanism in enhancing mechanical properties,Zr-12Nb-2Sn,Zr-13Nb-1Sn,and Zr-14Nb-3Sn alloys are selected.Results indicate that the TWIP mechanism leads to a significant improvement of strain-hardening rate and a uniform elongation of∼20%in Zr-12Nb-2Sn,which displays both{332}<113>mechanical twinning and disloca-tion slip as the primary deformation mechanisms.Conversely,Zr-14Nb-3Sn exhibits the typical mechan-ical properties found in stable body-centered cubic(BCC)alloys,characterized by the sole occurrence of dislocation slip.Cell viability tests confirm the superior biocompatibility of Zr-Nb-based alloys with deformation twins on the surface,in line with existing literature.Based on the whole set of results,a comprehensive design diagram is proposed.展开更多
Constructing a functional hybrid coating appears to be a promising strategy for addressing the poor corrosion resistance and insufficient endothelialization of Mg-based stents.Nevertheless,the steps for preparing comp...Constructing a functional hybrid coating appears to be a promising strategy for addressing the poor corrosion resistance and insufficient endothelialization of Mg-based stents.Nevertheless,the steps for preparing composite coatings are usually complicated and time-consuming.Herein,a novel composite coating,composed of bioactive magnesium thioctic acid(MTA)layer formed by deposition and corrosion-resistant magnesium hydroxide(Mg(OH)_(2))layer grown in situ,is simply fabricated on ZE21B alloys via one-step electrodeposition.Scanning electron microscopy(SEM)shows that the electrodeposited coating has a compact and uniform structure.And the high adhesion of the MTA/Mg(OH)_(2)hybrid coating is also confirmed by the micro-scratch test.Electrochemical test,scanning kelvin probe(SKP),and hydrogen evolution measurement indicate that the hybrid coating effectively reduces the degradation rate of Mg substrates.Haemocompatibility experiment and cell culture trial detect that the composite coating is of fine biocompatibility.Finally,the preparation mechanism of MTA/Mg(OH)_(2)hybrid coatings is discussed and proposed.This coating shows a great potential application for cardiovascular stents.展开更多
We report a facile solution method to form titanium oxide(TiO_(2))nano-flower structure on the titanium(Ti)substrates for realizing good physical sterilization and biocompatibility.We first prepare TiO_(2) nanotubes(N...We report a facile solution method to form titanium oxide(TiO_(2))nano-flower structure on the titanium(Ti)substrates for realizing good physical sterilization and biocompatibility.We first prepare TiO_(2) nanotubes(NT)with a diameter of about 80-100 nm and a length of about 5μm on Ti substrates by anodization,which is utilized as precursor.Then,we employ immersion treatment in different concentrations of phosphoric acid solution at 75℃ for 5 h to realize the transformation from TiO_(2) NT to TiO_(2) nano-flower structure.In addition,we studied the effects of phosphoric acid concentration(1 wt%,2.5 wt%,5 wt% and 10 wt%)on the TiO_(2) nano-flower structure,and the antibacterial properties and biocompatibility of the TiO_(2) nano-flower structure.The results show that TiO_(2) nano-flower structure become larger and thicker with the increase in the phosphoric acid concentration,and the thickness of the coating can reach 6.88μm.Meanwhile,the TiO_(2) nano-flower structure shows good physical sterilization effect,especially for the TiO_(2) nano-flower structure formed in 10 wt%H^(3)PO_(4) solution,the antibacterial rate can reach 95%.In addition,the TiO_(2) nano-flower structure have no toxicity to the osteoblasts and support cell growth.展开更多
AIM:To investigate the biocompatibility and bacterial adhesion properties of light responsive materials(LRM)and analyze the feasibility and biosafety of employing LRM in the preparation of accommodative intraocular le...AIM:To investigate the biocompatibility and bacterial adhesion properties of light responsive materials(LRM)and analyze the feasibility and biosafety of employing LRM in the preparation of accommodative intraocular lenses(AIOLs).METHODS:Employing fundamental experimental research techniques,LRM with human lens epithelial cells(hLECs)and human retinal pigment epithelium cells(ARPE-19 cells)were co-cultured.Commercially available intraocular lenses(IOLs)were used as controls to perform cell counting kit-8(CCK-8),cell staining under varying light intensities,cell adhesion and bacterial adhesion experiments.RESULTS:LRM exhibited a stronger inhibitory effect on the proliferation of ARPE19 cells than commercially available IOLs when co-cultured with the undiluted extract for 96h(P<0.05).Under other culturing conditions,the effects on the proliferation of hLECs and ARPE-19 cells were not significantly different between the two materials.Under the influence of light irradiation at intensities of 200 and 300 mW/cm^(2),LRM demonstrated a markedly higher inhibitory effect on the survival of hLECs compared to commercially available IOLs(P<0.0001).They also showed a stronger suppressive effect on the survival rate of ARPE-19 cells,with significant differences observed at 200 mW/cm^(2)(P<0.001)and extremely significant differences at 300 mW/cm^(2)(P<0.0001).Additionally,compared to commercially available IOLs,LRM had a higher number of cells adhering to their surface(P<0.05),as well as a significantly greater number of adherent bacterium(P<0.0001).CONCLUSION:LRM,characterized by their excellent non-contact tunable deformability and low cytotoxicity to ocular tissues,show considerable potential for use in the fabrication of AIOLs.These materials demonstrate strong cell adhesion;however,during photothermal conversion processes involving shape deformation under various light intensities,the resultant temperature rise may harm surrounding cells.These factors suggest that while the material plays a positive role in reducing the incidence of posterior capsule opacification(PCO),it also poses potential risks for retinal damage.Additionally,the strong bacterial adhesion of these materials indicates an increased risk of endophthalmitis.展开更多
Phospahting coated WE43 magnesium alloy was prepared by an immersion method. The microstructure, corrosion resistance and biocompatibility of the coated alloy were investigated. Scanning electron microscopy （SEM） an...Phospahting coated WE43 magnesium alloy was prepared by an immersion method. The microstructure, corrosion resistance and biocompatibility of the coated alloy were investigated. Scanning electron microscopy （SEM） and X-ray diffraction （XRD） were used to examine the microstructure and the composition of the coated alloy. The corrosion resistance was studied by means of potentiodynamic polarization method and the biocompatibility of the surface modified WE43 alloy was evaluated by （3-（4,5）-Dimethylthiazol-2, yl）-2,5-diphenyltetrazolium bromide （MTT） and hemolysis test. The results show that the phosphating coating can enhance the corrosion resistance of WE43 alloy and can be a good candidate to increase the biocompatibility of WE43 alloy.展开更多
A Mg?6%Zn?10%Ca3(PO4)2 composite with a chitosan coating was prepared to study its in vivo biodegradation properties. The chitosan dissolved in a 0.2% acetic acid solution was applied on the surface of Mg?6%Zn?10%Ca3(...A Mg?6%Zn?10%Ca3(PO4)2 composite with a chitosan coating was prepared to study its in vivo biodegradation properties. The chitosan dissolved in a 0.2% acetic acid solution was applied on the surface of Mg?6%Zn?10%Ca3(PO4)2 composite specimens and solidified at 60 °C for 30 min to form the coating. The cytotoxicity evaluation of chitosan coated specimens is at level 0, which indicates that such coating is safe for cellular applications. The in vivotests of chitosan coated composite show that the concentration of metal ions from the composite measured in the venous blood of Zelanian rabbits is less than that from the uncoated composite specimens. The chitosan coating impedes the in vivo degradation of the composite after surgery. The in vivo testing also indicates that the chitosan coated composite is harmless to important visceral organs, including the heart, kidneys and liver of the rabbits. The new bone formation surrounding the chitosan coated composite implant shows that the composite improves the concrescence of the bone tissues. And the chitosan coating is an effective corrosion resistant layer that reduces the hydrogen release of the implant composite, thereby decreasing the subcutaneous gas bubbles formed.展开更多
AIM: To establish an untransfected human corneal epithelial (HCEP) cell line and characterize its biocompatibility with denuded amniotic membrane (dAM). METHODS: The torn HCEP pieces were primarily cultured in DMEM/F1...AIM: To establish an untransfected human corneal epithelial (HCEP) cell line and characterize its biocompatibility with denuded amniotic membrane (dAM). METHODS: The torn HCEP pieces were primarily cultured in DMEM/F12 media (pH 7.2) supplemented with 20% fetal bovine serum and other necessary factors, yielding an HCEP cell line which was its growth performance, chromosome morphology, tumorigenicity and expression of marker proteins analyzed. In addition, the biocompatibility of HCEP cells with dAM was evaluated through histological and immunocytochemistry analyses and with light, electron and slit-lamp microscopies. RESULTS: HCEP cells proliferated to confluence in 3 weeks, which have been subcultured to passage 160. A continuous untransfected HCEP cell line, designated as utHCEPC01, was established with a population doubling time of 45.42 hours as was determined at passage 100. The cells retained HCEP cell properties as were approved by chromosomal morphology and the expression of keratin 3. They, with no tumorigenicity, formed a multilayer epithelium-like structure on dAMs through proliferation and differentiation during air-liquid interface culture, maintained expression of marker proteins including keratin 3 and integrin p 1 and attached tightly to dAMs. The reconstructed HCEP was highly transparent and morphologically and structurally similar to the original. CONCLUSION: An untransfected and non-tumorigenic HCEP cell line was established in this study. The cells maintained expression of marker proteins. The cell line was biocompatible with dAM. It holds the potential of being used for in vitro reconstruction of tissue-engineered HCEP, promising for the treatment of diseases caused by corneal epithelial disorders.展开更多
A TiO2 nanofilm was prepared on the surface of AZ31 magnesium alloy with controllable thickness through atomic layer deposition(ALD) technique, which can adjust the corrosion behaviors of AZ31 Mg alloy.Compared with t...A TiO2 nanofilm was prepared on the surface of AZ31 magnesium alloy with controllable thickness through atomic layer deposition(ALD) technique, which can adjust the corrosion behaviors of AZ31 Mg alloy.Compared with the untreated Mg alloys, corrosion current densities(icorr)can decline by 58% in the 200-cycles TiO2-covered Mg alloy and further decline by up to 74% with the thickness of nanofilm up to 63 nm(400 cycles).The subsequent modification with a cross-linked conversion layer of 3-aminopropyltriethoxysilane(APTES) by a dipping method can produce a compact silane coating on TiO2 nanofilm, which can seal pinholes of TiO2 nanofilm and serve as a barrier to further adjust the corrosion behavior of the substrate.The icorrcan decline about two orders of magnitude in the TiO2/silane composite coating.Making the adjustable corrosion rate come true, which can be attributed to the precise control on the thickness of metal oxide nanofilm and additional protection from the compact silane coating.In vitro study discloses that the TiO2/silane hybrid coating shows higher expression of alkaline phosphatase(ALP)and can promote cellular adhesion and proliferation with better cytocompatibility than untreated Mg alloy.展开更多
As yet,Mg alloys acting as the medical implants have drawn extensive attention,due to their spontaneous degrada bility,effective load-transmissibility and the excellent biocompatibility,particularly in bone tissue rec...As yet,Mg alloys acting as the medical implants have drawn extensive attention,due to their spontaneous degrada bility,effective load-transmissibility and the excellent biocompatibility,particularly in bone tissue reconstruction and vascular radial-support.Regrettably,they were inevitably affected by the tension/compression-torsion,dynamic erosion and corrosion fatigue under complex service conditions,which lead to premature failure of implantation-materials.Micro-alloying addition is an effective way to delay the rapid degradation,especially in rare-earth micro-composite addition.It can not only reduce intensities of galvanic-corrosion by refining the grain sizes and adjusting the Volta-potentials distribution of the precipitates,but also modify the compositions and biocompatibility of the degradation products.Moreover,the higher compress tress on the surface can improve the stability and densification of the film layer,which enhanced the corrosion resistance.Thus,the latest research progress about in vivo/vitro degradation behavio rs and bioco mpatibility of rare-earth Mg alloys is reviewed;The internal relationships between rare-earth elements,phase features and degradation behaviors of Mg alloys are summarized.Moreover,the effects of rare-earth addition on the film-characteristics are deeply explained,and the induced mechanisms of rare earth elements on the biocompatibility are revealed.展开更多
The performance of biodegradable magnesium alloy requires special attention to rapid degradation and poor biocompatibility, which can cause the implant to fail. Here, a sodium montmorillonite(MMT)/bovine serum albumin...The performance of biodegradable magnesium alloy requires special attention to rapid degradation and poor biocompatibility, which can cause the implant to fail. Here, a sodium montmorillonite(MMT)/bovine serum albumin(BSA) composite coating was prepared upon magnesium alloy AZ31 via hydrothermal synthesis, followed by dip coating. We evaluated the surface characterization and corrosion behavior in vitro, and the biocompatibility in vitro and in vivo. Biodegradation progress of the MMT-BSA coated Mg pieces was examined through hydrogen evolution, immersion tests, and electrochemical measurements in Hank’s solution. In vitro biocompatibility studies were evaluated via hemolysis tests, dynamic cruor time tests, platelet adhesion, MTT testing and live-dead stain of osteoblast cells(MC3 T3-E1). It was found that the MMT-BSA coating had good corrosion resistance and a marked improvement in biocompatibility in comparison to bare Mg alloy AZ31. in vivo studies were carried out in rat model and the degradation was characterized by computed tomography scans. Results revealed that the MMT-BSA coated Mg alloy AZ31 implants maintained their structural integrity and slight degradation after 120 d of post-implantation. A100% survival rate for the rats was observed with no obvious toxic damages on the organs and tissues.Additionally, we proposed a sound coating formation mechanism. Considering the good corrosion protection and biocompatibility, the MMT-BSA coated Mg alloy AZ31 is a promising candidate material for biomedical implants.展开更多
Mg-Ca alloys have recently attracted great attention towards the research in the field of orthopedic biodegradable implants.This study presents an in vitro degradation assessment of Mg-0.8Ca(0.8 wt.%of Ca)alloy in Han...Mg-Ca alloys have recently attracted great attention towards the research in the field of orthopedic biodegradable implants.This study presents an in vitro degradation assessment of Mg-0.8Ca(0.8 wt.%of Ca)alloy in Hank’s balanced salt solution(HBSS).Immersion,hydrogen evolution and electrochemical behavior was studied as well as the cytotoxicity of the degradation products.Morphology and phase composition of the corrosion products were studied using SEM,EDX and XRD techniques.Degradation in HBSS resulted in the formation of the needle-shaped carbonated hydroxyapatite which was similar to the biological apatite in the human bone.Degradation kinetics showed that Mg-0.8Ca alloy had approximately 3-fold faster degradation rate than the pure Mg(1.08±0.38 mm/year for Mg-0.8Ca and 0.35±0.17 mm/year for pure Mg),as observed in two independent experiments.Both,pure Mg and Mg-0.8Ca alloy were biocompatible,generating no cytotoxic degradation products against human-derived HEK 293 cells.Thus,the Mg-0.8Ca alloy was found to be a promising biodegradable implant in terms of bioactivity and compatibility with human cell lines.Depending on the application of the implant and the estimated healing time of the bone,the desired degradation rate of an implant can be controlled by the Mg-Ca composition of such alloys.展开更多
Although titanium and its alloys are extensively used in orthopedics and dentistry fields,implant failures still happen because of implant-associated infections.Herein,Au@Ag@Pt core–shell nanorods with noble metal co...Although titanium and its alloys are extensively used in orthopedics and dentistry fields,implant failures still happen because of implant-associated infections.Herein,Au@Ag@Pt core–shell nanorods with noble metal combination were fabricated and assembled on medical titanium surface and the antibacterial activity and biocompatibility were investigated.The results showed that antibacterial rates of Ti–Au@Ag@Pt against S.epidermidis and P.aeruginosa were 89.7%and 92.7%,respectively.Besides,Ti–Au@Ag@Pt showed no obvious cell toxicity with MC3 T3-E1 cells grew well on the sample surface.It was discovered that the Pt shell layer on Ti–Au@Ag@Pt slowed down the Ag ion release rate which endowed medical titanium surface with both antibacterial activity and good biocompatibility.展开更多
基金supported by National Natural Science Foundation of China(52271117)Educational Commission of Hunan Province of China(23A0107)High Technology Research and Development Program of Hunan Province of China(2022GK4038).
文摘To improve the corrosion resistance of biodegradable Mg alloys,WE43 alloys were implanted with Fe,Ti,Zn and Zr ions at the same implantation dose.The surface morphology,valence state of elements,nano-hardness(NH),elastic modulus(EM),degradation rate and in vitro cell experiments of the modified WE43 alloys were systematically studied.A modified layer composed of Mg,MgO,the implanted elements and their oxides was formed on the modified alloys.Since high-speed metal ions caused severe surface lattice damage,the surface hardness of the substrate considerable increased.Electrochemical tests demonstrated a substantial enhancement in the corrosion resistance of the modified alloys via the implantation of Ti and Zr ions,resulting in a reduction of the corrosion current density to 88.1±9.9 and 15.6±11.4μA cm^(−2),respectively,compared with the implantation of Fe and Zn ions.Biocompatibility tests showed that the implantation of Fe,Ti,Zn and Zr ions enhanced the anticoagulant and hemolytic resistance of the WE43 alloy.All surface-modified samples showed negligible cytotoxicity(0-1)at 12.5%extract concentration.Moreover,the alloys implanted with Fe,Ti and Zn ions significantly promoted proliferation of human umbilical vein endothelial cells(HUVEC)compared with the unmodified alloy.The results demonstrate that Ti ion implantation is the best choice for WE43 alloy modification to achieve outstanding corrosion resistance and biocompatibility.
基金supported by the Natural Science Foundation of Chongqing(Grant No.csts2018jcyjAX0016)Funded by the Senior Medical Talents Program of Chongqing for Young and Middle-aged.
文摘The possible application of magnesium(Mg)in glaucoma surgical treatment has been investigated in our previous work.In this paper,the degradation behavior and biocompatibility of Mg coated with hydroxyapatite(HA)and dicalcium phosphate dihydrate(DCPD)in eye environment were evaluated,and uncoated Mg was used for comparison.It was found that uniform corrosion occurred macroscopically to the coated Mg samples in sodium lactate ringer’s injection(SLRI)as well as in the rabbit eyes.In micro-scale,the corrosion was characterized by local cracking and pitting primarily.Mg and calcium(Ca)were incorporated into the surface corrosion products and a multi-layer structure was formed.Compared to other samples,HA-coated Mg slowed down dramatically the alkalinity of the solution and the ion release of the sample,and exhibited the lowest corrosion rate in SLRI,which was about 0.22 mm/a.In terms of biocompatibility,fibroblasts demonstrated high viability in the HA-coated and DCPD-coated Mg groups(p<0.05)in vitro.In vivo,HA-coated Mg was found to show lower inflammatory response and fibrosis than the other groups did,as indicated by hematoxylin-eosin and immunofluorescence staining.During the degrading process of HA-coated Mg in the rabbits’eyes,no inflammation was found in the anterior chamber,lens,and vitreous body.HA-coated Mg was fully biodegraded fifteen weeks post-operation,and the scleral drainage channel(SDC)was formed without obvious scarring.It is concluded that HA-coated Mg implantation is a promising adjunctive procedure to improve the success rate of trabeculectomy.Statement of significance:Magnesium(Mg)has shown to be a potential biomaterial for ophthalmic implants in our previous work.However,inflammatory response resulted from the low corrosion resistance of Mg is a major concern.It is shown here that Mg coated with different calcium phosphates can improve these properties in varying degrees and keep the scleral drainage channel unobstructed and unscarred.Based on our in vitro and in vivo studies,HA-coated Mg exhibited a better degradation behavior and excellent biocompatibility.The scleral drainage channel still exists and aqueous humor flows out smoothly after the full degradation of the implant.It is concluded that HA-coated Mg is a promising biomaterial to increase the therapeutic efficiency of trabeculectomy for glaucoma.
基金supported by the National Natural Science Foundation of China(Nos.52371070 and 52271249),the Key Research and Development Program of Shaanxi,China(No.2023-YBGY-488)the State Key Laboratory of Solidification Processing in Northwestern Polytechnical University(No.SKLSP202415)Additional support was provided by the Xi’an Talent Plan,China(No.XAYC240016)。
文摘Although the degradability and biosafety of magnesium alloys make them advantageous for biological applications,medical implants made of magnesium alloys often fail prematurely due to corrosion.Therefore,improving the corrosion resistance of magnesium alloys has become an urgent problem in the alloy design process.In this study,we designed and prepared Mg-xZn-0.5Y-0.5Zr(x=1,2,and 3,wt%)alloys in a hot extruded state and analyzed their surface structure through scanning electron microscopy,energy dispersion spectrometry,and X-ray diffraction.It was found that increasing the Zn content refined the recrystallized grains in the alloy.Particularly in Mg-3Zn-0.5Y-0.5Zr,the I phase became finer,forming both granular and nanoscale needle-like particles.Surface characterization after the immersion experiment showed that the corrosion product layer was mainly composed of Mg(OH)_(2),Zn(OH)_(2),CaCO_(3),and hy-droxyapatite.The degradation rate of ZW305K was the lowest,measured as 4.1 and 6.0 mm·a^(-1) with the hydrogen precipitation method and weight loss method respectively.Electrochemical experiments further explained the corrosion circuit model of the alloy in solution and confirmed the earlier results.The maximum polarization resistance of ZW305K was 874.5Ω·cm^(2),and the lowest corrosion current density was 0.104 mA·cm^(-2).As a biomedical alloy,it must exhibit good biocompatibility,so the alloy was also tested through cytotoxicity,cell adhesion,and staining experiments.The cell viability of each group after 48 h was greater than 80%,showing that the addition of zinc enhances the alloy’s biocompatibility.In summary,the prepared alloys have the potential to be used as biodegradable implant materials.
基金supported by the National Natural Science Foundation of China(Grant No.52071051)the(Key)Foundation of Xi'an Key Laboratory of High-Performance Titanium Alloy(No.NIN-HTL-2022-ZD01).
文摘Ti-Mo-O alloys were used to analyze the effect of Mo and O contents on the mechanical compatibility and biocompatibility.The bending modulus,bending yield strength and springback ratio of the alloys were evaluated by using three-point bending tests and bending load-unloading tests.The biocompatibility was investigated by the adhesion,proliferation and the alkaline phosphatase(ALP)activity of mouse osteoblast-like cells(MC3T3-E1).The results showed that the bending modulus and bending yield strength first were increased and then decreased with the increase in Mo content,while the springback ratio exhibited an opposite trend to the bending modulus.With the increase in O content,the bending modulus remained almost constant,while the bending yield strength was increased.The springback ratio exhibited a similar trend to the bending yield strength.The in vitro biological experiments showed that the Ti-Mo-O alloys had excellent biocompatibility due to the formed stable oxide films on their surface.With the increase in O and Mo contents,the TiO_(2)-MoO_(2)oxide film became denser.Combining with mechanical compatibility and biocompatibility,the Ti-15Mo-0.2O and Ti-15Mo-0.3O alloys were more suitable for the biomedical application of spinal fixation device.
基金funded by the National Centre for Research and Development in Poland, project V4-JAPAN/2/15 “Development of Advanced Magnesium Alloys for Multifunctional Applications in Extreme Environments,” under statutory work at the Faculty of Material Science and Engineering Warsaw University of Technology in Polandthe International Visegrad Fund (project no. JP39421, V4Japan Joint Research Program)+3 种基金the support of the International Visegrad Fund (project V4Japan Joint Research Program, Ref. JP3936)the National Research, Development and Innovation Office (contract no. 2019-2.1.7-ERA-NET-2021-00030)Support by the Ministry of Education, Youth and Sports of the Czech Republic in the framework of Visegrad Group (V4)-Japan Joint Research Program-Advanced Materials under grant no. 8F21011 is gratefully acknowledged by K.M., D.D., and A.Fthe support from the Department of Metal and Corrosion Engineering, University of Chemical Technology, Prague, Czech Republic, while performing the tribocorrosion measurements
文摘In this study,the effect of annealing on the microstructure and following corrosion and biological properties of Mg-1.0Ca-0.5Zn-0.1Y-0.03Mn(at.%)alloy prepared by rapid solidified powder metallurgy was investigated.The annealing at 300℃ for 2 h did not change the grain size significantly;however,a slight growth of Mg_(2)Ca precipitates was observed.When the annealing temperature increased up to 400℃ for 2 h,full recrystallization of the alloy occurred;the grains and precipitates grew noticeably.Those changes were responsible for decreasing the corrosion and the tribocorrosion resistance of the alloy.Due to lowered resistance to the corrosion medium,the cell viability was also reduced.Although MG63 cells on the annealed specimens developed filopodia,cell-to-cell communication was not observed.
基金the financial support by the Natural Science Foundation of Ningxia(Grant no.2022AAC03099)the Key R&D Project of Ningxia(Grant no.2020BDE03012)。
文摘Corrosion-resistant and biocompatible films were fabricated on AZ91D Mg alloy substrates by varying their roughness levels using met-allographic preparation and subsequent hydrothermal procedures.The coated films comprised a mixed structure of Mg(OH)_(2)and Mg-Al layered double hydroxides(LDH)and exhibited excellent compactness.Coating film thickness increased with decreasing surface roughness.Corrosion resistance was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy.Metallographic pretreat-ment influenced the chemical activity of the Mg alloy surface and helped modulate the dissolution rate of the Mg_(17)Al_(12)phase during the hydrothermal procedure.With decreasing roughness of the Mg substrate,the Al^(3+)concentration gradually increased,accelerating the in-situ formation of the Mg(OH)_(2)/LDH composite coating and improving its crystallinity.A thick and dense Mg(OH)_(2)/LDH coating was synthesized on the Mg substrate with the least roughness,substantially improving the corrosion resistance of the AZ91D alloy.The lowest corrosion current density((5.73±2.75)×10^(−8)A·cm^(−2))was achieved,which was approximately three orders of magnitude less than that of bare AZ91D.Moreover,the coating demonstrated biocompatibility with no evident cytotoxicity,cellular damage,and hemolytic phenomena.This study provides an effective method for preparing coatings on Mg alloy surfaces with excellent corrosion resistance and biocompatibility.
基金supported by the National Natural Science Foundation of China[Grant no.51821004].
文摘Developing high-performance aqueous Zn-ion batteries from sustainable biomass becomes increasingly vital for large-scale energy storage in the foreseeable future.Therefore,γ-MnO_(2) uniformly loaded on N-doped carbon derived from grapefruit peel is successfully fabricated in this work,and particularly the composite cathode with carbon carrier quality percentage of 20 wt%delivers the specific capacity of 391.2 mAh g^(−1)at 0.1 A g^(−1),outstanding cyclic stability of 92.17%after 3000 cycles at 5 A g^(−1),and remarkable energy density of 553.12 Wh kg^(−1) together with superior coulombic efficiency of~100%.Additionally,the cathodic biosafety is further explored specifically through in vitro cell toxicity experiments,which verifies its tremendous potential in the application of clinical medicine.Besides,Zinc ion energy storage mechanism of the cathode is mainly discussed from the aspects of Jahn–Teller effect and Mn domains distribution combined with theoretical analysis and experimental data.Thus,a novel perspective of the conversion from biomass waste to biocompatible Mn-based cathode is successfully developed.
基金supported by the Hunan Provincial Science and Technology Department Project(2015WK3012)the National Natural Science Foundation of China(No.81571021)+3 种基金R&D of Key Project of Hunan Provincial Science and Technology Department(2022SK2010)R&D of Key Technology of Light Metal Air Battery,Transformation and Industrialization of Scientific and Technological Achievements of Hunan Province(2020GK2071)R&D of Key Technology and Materials of Magnesium Air Battery,Transformation of Scientific and Technological Achievements of Changsha City(Kh2005186)Technology Fundation(2021JCJQ-JJ-0432)。
文摘The repair and regeneration of bone defects are highly challenging orthopedic problems.Recently,Mg-based implants have gained popularity due to their unique biodegradation and elastic modulus similar to that of human bone.The aim of our study is to develop a magnesium alloy with a controllable degradation that can closely match bone tissue to help injuries heal in vivo and avoid cytotoxicity caused by a sudden increase in ion concentration.In this study,we prepared and modified Mg-3Zn,Mg-3Zn-1Y,and Mg-2Zn-1Mn by hot extrusion,and used Mg-2.5Y-2.5Nd was as a control.We then investigated the effect of additions of Y and Mn on alloys'properties.Our results show that Mn and Y can improve not only compression strength but also corrosion resistance.The alloy Mg-2Zn-1Mn demonstrated good cytocompatibility in vitro,and for this reason we selected it for implantation in vivo.The degraded Mg-2Zn-1Mn implanted a bone defect area did not cause obvious rejection and inflammatory reaction,and the degradation products left no signs of damage to the heart,liver,kidney,or brain.Furthermore,we find that Mg-2Zn-1Mn can promote an osteoinductive response in vivo and the formation of bone regeneration.
基金the support of the French Agence Nationale de la Recherche(ANR),under grant ANR-21-CE08-0022(project ISANAMI)Junhui TANG is sponsored by the China Scholarship Council.
文摘This study proposes a novel strategy for the design of a new family of metastable Zr alloys.These al-loys offer improved mechanical properties for implants,particularly in applications where conventional stainless steels and Co-Cr alloys are currently used but lack suitability.The design approach is based on the controlled twinning-induced plasticity(TWIP)effect,significantly enhancing the ductility and strain-hardenability of the Zr alloys.In order to draw a“blueprint”for the compositional design of biomedical T WIP(Bio-T WIP)Zr alloys-using only non-toxic elements,the study combines D-electron phase stability calculations(specifically bond order(Bo)and mean d-orbital energy(Md))with a systematic experimental screening of active deformation mechanisms within the Zr-Nb-Sn alloy system.This research aids in ac-curately identifying the TWIP line,which signifies the mechanism shift between TWIP and classic slip as the primary deformation mechanism.To demonstrate the efficacy of the TWIP mechanism in enhancing mechanical properties,Zr-12Nb-2Sn,Zr-13Nb-1Sn,and Zr-14Nb-3Sn alloys are selected.Results indicate that the TWIP mechanism leads to a significant improvement of strain-hardening rate and a uniform elongation of∼20%in Zr-12Nb-2Sn,which displays both{332}<113>mechanical twinning and disloca-tion slip as the primary deformation mechanisms.Conversely,Zr-14Nb-3Sn exhibits the typical mechan-ical properties found in stable body-centered cubic(BCC)alloys,characterized by the sole occurrence of dislocation slip.Cell viability tests confirm the superior biocompatibility of Zr-Nb-based alloys with deformation twins on the surface,in line with existing literature.Based on the whole set of results,a comprehensive design diagram is proposed.
基金the National Key Research and Development Program of China(2018YFC1106703)the National Natural Science Foundation of China(No.U1804251)。
文摘Constructing a functional hybrid coating appears to be a promising strategy for addressing the poor corrosion resistance and insufficient endothelialization of Mg-based stents.Nevertheless,the steps for preparing composite coatings are usually complicated and time-consuming.Herein,a novel composite coating,composed of bioactive magnesium thioctic acid(MTA)layer formed by deposition and corrosion-resistant magnesium hydroxide(Mg(OH)_(2))layer grown in situ,is simply fabricated on ZE21B alloys via one-step electrodeposition.Scanning electron microscopy(SEM)shows that the electrodeposited coating has a compact and uniform structure.And the high adhesion of the MTA/Mg(OH)_(2)hybrid coating is also confirmed by the micro-scratch test.Electrochemical test,scanning kelvin probe(SKP),and hydrogen evolution measurement indicate that the hybrid coating effectively reduces the degradation rate of Mg substrates.Haemocompatibility experiment and cell culture trial detect that the composite coating is of fine biocompatibility.Finally,the preparation mechanism of MTA/Mg(OH)_(2)hybrid coatings is discussed and proposed.This coating shows a great potential application for cardiovascular stents.
基金jointly supported by the Four“Batches”Innovation Project of Invigorating Medical through Science and Technology of Shanxi Province(2022XM12)the Central Leading Science and Technology Development Foundation of Shanxi Province(YDZJSX2021A019)+1 种基金the Key Research and Development Program of Shanxi Province(202102130501007)the Natural Science Foundation of Shanxi Province(202103021223102,202203021222127).
文摘We report a facile solution method to form titanium oxide(TiO_(2))nano-flower structure on the titanium(Ti)substrates for realizing good physical sterilization and biocompatibility.We first prepare TiO_(2) nanotubes(NT)with a diameter of about 80-100 nm and a length of about 5μm on Ti substrates by anodization,which is utilized as precursor.Then,we employ immersion treatment in different concentrations of phosphoric acid solution at 75℃ for 5 h to realize the transformation from TiO_(2) NT to TiO_(2) nano-flower structure.In addition,we studied the effects of phosphoric acid concentration(1 wt%,2.5 wt%,5 wt% and 10 wt%)on the TiO_(2) nano-flower structure,and the antibacterial properties and biocompatibility of the TiO_(2) nano-flower structure.The results show that TiO_(2) nano-flower structure become larger and thicker with the increase in the phosphoric acid concentration,and the thickness of the coating can reach 6.88μm.Meanwhile,the TiO_(2) nano-flower structure shows good physical sterilization effect,especially for the TiO_(2) nano-flower structure formed in 10 wt%H^(3)PO_(4) solution,the antibacterial rate can reach 95%.In addition,the TiO_(2) nano-flower structure have no toxicity to the osteoblasts and support cell growth.
基金Supported by the National Natural Science Foundation of China(No.52073181,No.52273134).
文摘AIM:To investigate the biocompatibility and bacterial adhesion properties of light responsive materials(LRM)and analyze the feasibility and biosafety of employing LRM in the preparation of accommodative intraocular lenses(AIOLs).METHODS:Employing fundamental experimental research techniques,LRM with human lens epithelial cells(hLECs)and human retinal pigment epithelium cells(ARPE-19 cells)were co-cultured.Commercially available intraocular lenses(IOLs)were used as controls to perform cell counting kit-8(CCK-8),cell staining under varying light intensities,cell adhesion and bacterial adhesion experiments.RESULTS:LRM exhibited a stronger inhibitory effect on the proliferation of ARPE19 cells than commercially available IOLs when co-cultured with the undiluted extract for 96h(P<0.05).Under other culturing conditions,the effects on the proliferation of hLECs and ARPE-19 cells were not significantly different between the two materials.Under the influence of light irradiation at intensities of 200 and 300 mW/cm^(2),LRM demonstrated a markedly higher inhibitory effect on the survival of hLECs compared to commercially available IOLs(P<0.0001).They also showed a stronger suppressive effect on the survival rate of ARPE-19 cells,with significant differences observed at 200 mW/cm^(2)(P<0.001)and extremely significant differences at 300 mW/cm^(2)(P<0.0001).Additionally,compared to commercially available IOLs,LRM had a higher number of cells adhering to their surface(P<0.05),as well as a significantly greater number of adherent bacterium(P<0.0001).CONCLUSION:LRM,characterized by their excellent non-contact tunable deformability and low cytotoxicity to ocular tissues,show considerable potential for use in the fabrication of AIOLs.These materials demonstrate strong cell adhesion;however,during photothermal conversion processes involving shape deformation under various light intensities,the resultant temperature rise may harm surrounding cells.These factors suggest that while the material plays a positive role in reducing the incidence of posterior capsule opacification(PCO),it also poses potential risks for retinal damage.Additionally,the strong bacterial adhesion of these materials indicates an increased risk of endophthalmitis.
基金Project(2011AA030103) supported by the National High-tech Research Program of ChinaProject(201001C0104669453) supported by the Guangdong Innovation R&D Team Project,China
文摘Phospahting coated WE43 magnesium alloy was prepared by an immersion method. The microstructure, corrosion resistance and biocompatibility of the coated alloy were investigated. Scanning electron microscopy （SEM） and X-ray diffraction （XRD） were used to examine the microstructure and the composition of the coated alloy. The corrosion resistance was studied by means of potentiodynamic polarization method and the biocompatibility of the surface modified WE43 alloy was evaluated by （3-（4,5）-Dimethylthiazol-2, yl）-2,5-diphenyltetrazolium bromide （MTT） and hemolysis test. The results show that the phosphating coating can enhance the corrosion resistance of WE43 alloy and can be a good candidate to increase the biocompatibility of WE43 alloy.
基金Project(2014)supported by the Open Fund of the State Key Laboratory of Powder Metallurgy,China
文摘A Mg?6%Zn?10%Ca3(PO4)2 composite with a chitosan coating was prepared to study its in vivo biodegradation properties. The chitosan dissolved in a 0.2% acetic acid solution was applied on the surface of Mg?6%Zn?10%Ca3(PO4)2 composite specimens and solidified at 60 °C for 30 min to form the coating. The cytotoxicity evaluation of chitosan coated specimens is at level 0, which indicates that such coating is safe for cellular applications. The in vivotests of chitosan coated composite show that the concentration of metal ions from the composite measured in the venous blood of Zelanian rabbits is less than that from the uncoated composite specimens. The chitosan coating impedes the in vivo degradation of the composite after surgery. The in vivo testing also indicates that the chitosan coated composite is harmless to important visceral organs, including the heart, kidneys and liver of the rabbits. The new bone formation surrounding the chitosan coated composite implant shows that the composite improves the concrescence of the bone tissues. And the chitosan coating is an effective corrosion resistant layer that reduces the hydrogen release of the implant composite, thereby decreasing the subcutaneous gas bubbles formed.
基金Supported by National High Technology Research and Development Program ("863" Program) of China(No. 2006AA02A132)
文摘AIM: To establish an untransfected human corneal epithelial (HCEP) cell line and characterize its biocompatibility with denuded amniotic membrane (dAM). METHODS: The torn HCEP pieces were primarily cultured in DMEM/F12 media (pH 7.2) supplemented with 20% fetal bovine serum and other necessary factors, yielding an HCEP cell line which was its growth performance, chromosome morphology, tumorigenicity and expression of marker proteins analyzed. In addition, the biocompatibility of HCEP cells with dAM was evaluated through histological and immunocytochemistry analyses and with light, electron and slit-lamp microscopies. RESULTS: HCEP cells proliferated to confluence in 3 weeks, which have been subcultured to passage 160. A continuous untransfected HCEP cell line, designated as utHCEPC01, was established with a population doubling time of 45.42 hours as was determined at passage 100. The cells retained HCEP cell properties as were approved by chromosomal morphology and the expression of keratin 3. They, with no tumorigenicity, formed a multilayer epithelium-like structure on dAMs through proliferation and differentiation during air-liquid interface culture, maintained expression of marker proteins including keratin 3 and integrin p 1 and attached tightly to dAMs. The reconstructed HCEP was highly transparent and morphologically and structurally similar to the original. CONCLUSION: An untransfected and non-tumorigenic HCEP cell line was established in this study. The cells maintained expression of marker proteins. The cell line was biocompatible with dAM. It holds the potential of being used for in vitro reconstruction of tissue-engineered HCEP, promising for the treatment of diseases caused by corneal epithelial disorders.
基金financially supported by the Natural Science Fund of Hubei Province (No.2018CFA064)the National Natural Science Foundation of China (NSFC) (Nos.51671081 and 51422102)+4 种基金the National Key Research and Development Program of China (No.2016YFC1100600, sub-project 2016YFC1100604)the Hong Kong Research Grants Council (RGC) General Research Funds (GRF) (Nos.11301215, 11205617 and 17214516)RGC/NSFC (N_HKU725-16)the Hong Kong Innovation and Technology Commission (ITC) (Nos.ITS/287/17 and GHX/002/14SZ)the Health and Medical Research Fund (No.03142446)
文摘A TiO2 nanofilm was prepared on the surface of AZ31 magnesium alloy with controllable thickness through atomic layer deposition(ALD) technique, which can adjust the corrosion behaviors of AZ31 Mg alloy.Compared with the untreated Mg alloys, corrosion current densities(icorr)can decline by 58% in the 200-cycles TiO2-covered Mg alloy and further decline by up to 74% with the thickness of nanofilm up to 63 nm(400 cycles).The subsequent modification with a cross-linked conversion layer of 3-aminopropyltriethoxysilane(APTES) by a dipping method can produce a compact silane coating on TiO2 nanofilm, which can seal pinholes of TiO2 nanofilm and serve as a barrier to further adjust the corrosion behavior of the substrate.The icorrcan decline about two orders of magnitude in the TiO2/silane composite coating.Making the adjustable corrosion rate come true, which can be attributed to the precise control on the thickness of metal oxide nanofilm and additional protection from the compact silane coating.In vitro study discloses that the TiO2/silane hybrid coating shows higher expression of alkaline phosphatase(ALP)and can promote cellular adhesion and proliferation with better cytocompatibility than untreated Mg alloy.
基金Project supported by the Central Government Guided Local Science and Technology Development Funds (226Z1004G)Natural Science Foundation of Hebei Province (E2020209153)State Key Lab of Advanced Metals and Materials (2020-Z12)。
文摘As yet,Mg alloys acting as the medical implants have drawn extensive attention,due to their spontaneous degrada bility,effective load-transmissibility and the excellent biocompatibility,particularly in bone tissue reconstruction and vascular radial-support.Regrettably,they were inevitably affected by the tension/compression-torsion,dynamic erosion and corrosion fatigue under complex service conditions,which lead to premature failure of implantation-materials.Micro-alloying addition is an effective way to delay the rapid degradation,especially in rare-earth micro-composite addition.It can not only reduce intensities of galvanic-corrosion by refining the grain sizes and adjusting the Volta-potentials distribution of the precipitates,but also modify the compositions and biocompatibility of the degradation products.Moreover,the higher compress tress on the surface can improve the stability and densification of the film layer,which enhanced the corrosion resistance.Thus,the latest research progress about in vivo/vitro degradation behavio rs and bioco mpatibility of rare-earth Mg alloys is reviewed;The internal relationships between rare-earth elements,phase features and degradation behaviors of Mg alloys are summarized.Moreover,the effects of rare-earth addition on the film-characteristics are deeply explained,and the induced mechanisms of rare earth elements on the biocompatibility are revealed.
基金financially supported by the National Nature Science Foundation of China(Nos.51571134 and 51601108)the Shandong University of Science and Technology Research Fund(No.2014TDJH104)。
文摘The performance of biodegradable magnesium alloy requires special attention to rapid degradation and poor biocompatibility, which can cause the implant to fail. Here, a sodium montmorillonite(MMT)/bovine serum albumin(BSA) composite coating was prepared upon magnesium alloy AZ31 via hydrothermal synthesis, followed by dip coating. We evaluated the surface characterization and corrosion behavior in vitro, and the biocompatibility in vitro and in vivo. Biodegradation progress of the MMT-BSA coated Mg pieces was examined through hydrogen evolution, immersion tests, and electrochemical measurements in Hank’s solution. In vitro biocompatibility studies were evaluated via hemolysis tests, dynamic cruor time tests, platelet adhesion, MTT testing and live-dead stain of osteoblast cells(MC3 T3-E1). It was found that the MMT-BSA coating had good corrosion resistance and a marked improvement in biocompatibility in comparison to bare Mg alloy AZ31. in vivo studies were carried out in rat model and the degradation was characterized by computed tomography scans. Results revealed that the MMT-BSA coated Mg alloy AZ31 implants maintained their structural integrity and slight degradation after 120 d of post-implantation. A100% survival rate for the rats was observed with no obvious toxic damages on the organs and tissues.Additionally, we proposed a sound coating formation mechanism. Considering the good corrosion protection and biocompatibility, the MMT-BSA coated Mg alloy AZ31 is a promising candidate material for biomedical implants.
基金The authors would like to thank the Helmholtz-Zentrum Geesthacht and Fesil Company(Germany)for the alloys syn-thesis and casting.
文摘Mg-Ca alloys have recently attracted great attention towards the research in the field of orthopedic biodegradable implants.This study presents an in vitro degradation assessment of Mg-0.8Ca(0.8 wt.%of Ca)alloy in Hank’s balanced salt solution(HBSS).Immersion,hydrogen evolution and electrochemical behavior was studied as well as the cytotoxicity of the degradation products.Morphology and phase composition of the corrosion products were studied using SEM,EDX and XRD techniques.Degradation in HBSS resulted in the formation of the needle-shaped carbonated hydroxyapatite which was similar to the biological apatite in the human bone.Degradation kinetics showed that Mg-0.8Ca alloy had approximately 3-fold faster degradation rate than the pure Mg(1.08±0.38 mm/year for Mg-0.8Ca and 0.35±0.17 mm/year for pure Mg),as observed in two independent experiments.Both,pure Mg and Mg-0.8Ca alloy were biocompatible,generating no cytotoxic degradation products against human-derived HEK 293 cells.Thus,the Mg-0.8Ca alloy was found to be a promising biodegradable implant in terms of bioactivity and compatibility with human cell lines.Depending on the application of the implant and the estimated healing time of the bone,the desired degradation rate of an implant can be controlled by the Mg-Ca composition of such alloys.
基金financially supported by the National Natural Science Foundation of China(No.51831011)Shanghai Scientific and Technological Innovation Project(No.20ZR1452200)+3 种基金the Program for Outstanding Medical Academic Leader(No.2019LJ27)the PhD Research Startup Foundation of Jiamusi University(No.JMSUBZ2019-09)Shanghai Medical Key Specialty(No.ZK2019B12)China Postdoctoral Science Foundation(No.2019M661642)。
文摘Although titanium and its alloys are extensively used in orthopedics and dentistry fields,implant failures still happen because of implant-associated infections.Herein,Au@Ag@Pt core–shell nanorods with noble metal combination were fabricated and assembled on medical titanium surface and the antibacterial activity and biocompatibility were investigated.The results showed that antibacterial rates of Ti–Au@Ag@Pt against S.epidermidis and P.aeruginosa were 89.7%and 92.7%,respectively.Besides,Ti–Au@Ag@Pt showed no obvious cell toxicity with MC3 T3-E1 cells grew well on the sample surface.It was discovered that the Pt shell layer on Ti–Au@Ag@Pt slowed down the Ag ion release rate which endowed medical titanium surface with both antibacterial activity and good biocompatibility.
