The Experts below are selected from a list of 2145 Experts worldwide ranked by ideXlab platform
Erlin Zhang - One of the best experts on this subject based on the ideXlab platform.
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in vivo evaluation of biodegradable Magnesium alloy bone Implant in the first 6 months Implantation
Journal of Biomedical Materials Research Part A, 2009Co-Authors: Erlin Zhang, Feng Pan, Ke YangAbstract:In vivo degradation of Magnesium alloy Implant, the bone response to the Magnesium, and the effect of the degradation of Magnesium on the blood composition and organs were investigated by using light microscopy and scanning electronic microscopy with energy dispersive spectrum. Magnesium alloy showed different degradation rates in the marrow channel and the cortical bone. More degradation of Magnesium Implant was observed in the marrow channel than in the cortical bone. New bone tissue formed around the Magnesium Implants after 6 weeks Implantation but no fibrous capsule was found. There existed two distinct layers separating the new bone tissue from the Magnesium Implant. On the Magnesium Implant side, crystalline Magnesium calcium phosphate formed on the surface of the Implant due to the reaction between the Implant and blood or body fluid. On the new bone tissue side was a 10-30-microm membrane comprising two distinct layers with many fibroblasts in the layer close to the new bone tissue. The new bone was in tight contact with the Implant through the membrane and phosphate layer due to the good osteoconductivity of the phosphate layer. After 10 and 26 weeks postImplantation, more new bone tissues as well as the membrane were found around the Implant. However, no apparent increase in the thickness of the membrane was observed with the increasing of the Implantation duration. Blood examination has shown that the degradation of the Magnesium Implant caused little change to blood composition but no disorder to liver or kidneys.
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biocorrosion behavior of Magnesium alloy in different simulated fluids for biomedical application
Materials Science and Engineering: C, 2009Co-Authors: Lei Yang, Erlin ZhangAbstract:Abstract The biocorrosion behavior of a Magnesium alloy in two simulated body solutions, Hank's solution and simulated blood plasma (SBP) solution was investigated by electrochemical and weight loss testing for biomedical application. The solution volume/surface area (SV/SA) ratio was changed to reveal the effect of immersion condition on the biocorrosion behavior. A same tendency was observed in the corrosion rate of Magnesium alloy in all testing conditions: a high corrosion rate at the initial stage, and rapid decrease in the first 2–3 days followed by a stable corrosion rate in the following stage. A higher corrosion rate was observed in Hank's solution than in SBP solution due to high Cl−, low Ca2+ and PO43− concentration in Hank's solution. However, no difference in the surface reaction product was observed between the samples immersed in Hank's solution and in SBP solution. It was found that the SV/SA ratio significantly affected the corrosion rate of Magnesium alloy. Low ratio resulted in a high pH, which resisted the corrosion. But when the ratio was high enough, 6.7 for example, the influence was negligible. By changing the ratio, the biocorrosion behavior of Magnesium Implant in different Implantation sites can be simulated, for example, low ratio for the case of in muscle and high ratio for the case of in marrow cavity. It is suggested that selection of the simulated solution and the SV/SA ratio would be very necessary to simulate different the in-vivo biodegradation behavior of Magnesium in different Implantation environment.
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biocorrosion behavior of Magnesium alloy in different simulated fluids for biomedical application
Materials Science and Engineering: C, 2009Co-Authors: Lei Yang, Erlin ZhangAbstract:The biocorrosion behavior of a Magnesium alloy in two simulated body solutions, Hank's Solution and simulated blood plasma (SBP) solution was investigated by electrochemical and weight loss testing for biomedical application. The solution volume/surface area (SV/SA) ratio was changed to reveal the effect of immersion condition on the biocorrosion behavior. A same tendency was observed in the corrosion rate of Magnesium alloy in all testing conditions: a high corrosion rate at the initial stage, and rapid decrease in the first 2-3 days followed by a stable corrosion rate in the following stage. A higher corrosion rate was observed in Hank's solution than in SBP solution due to high Cl(-), low Ca(2+) and PO(4)(3-) concentration in Hank's solution. However, no difference in the surface reaction product was observed between the samples immersed in Hank's solution and in SBP solution. It was found that the SV/SA ratio significantly affected the corrosion rate of Magnesium alloy. Low ratio resulted ill a high pH, which resisted the corrosion. But When the ratio was high enough, 6.7 for example, the influence was negligible. By changing the ratio, the biocorrosion behavior of Magnesium Implant in different Implantation sites can be simulated, for example, low ratio for the case of in muscle and high ratio for the case of in marrow cavity. It is suggested that selection of the simulated solution and the SV/SA ratio would be very necessary to Simulate different the in-vivo biodegradation behavior of Magnesium in different Implantation environment. (C) 2009 Elsevier B.V. All rights reserved.
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in vivo corrosion behavior of mg mn zn alloy for bone Implant application
Journal of Biomedical Materials Research Part A, 2007Co-Authors: Erlin Zhang, Feng Pan, Ke YangAbstract:Magnesium alloy has been Implanted in rats to investigate the in vivo degradation behavior of Magnesium for bone Implant application. After 9 weeks postoperation, 100% Implants were fixed and no inflammation was observed. Histological analysis showed new bone was formed around Magnesium Implant and no difference was found in the histological microstructure of the new bone and the cortical bone. A degradation or reaction layer, which was mainly composed of Ca, P, O, and Mg, was formed on the surface of Magnesium alloy Implants. High Ca content in the degradation layer displayed that Magnesium could promote the deposition of Ca. Residual area calculation has showed that 10-17% Magnesium alloy Implant has been degraded in vivo. Compared with that of the controlled rats, no increase in serum Magnesium and no disorder of kidney were observed after 15 weeks postoperation. After 18 weeks postoperation, 100% Magnesium Implants were fixed and no inflammation was observed. About 54% Magnesium Implant has degraded in vivo. Element analysis showed that Zn and Mn in Mg-Mn-Zn alloy distributed homogeneously in the residual Magnesium Implant, the degradation layer, and the surrounding bone tissue after 18 weeks Implantation, indicating that Zn and Mn elements were easily absorbed by bioenvironment. (C) 2007 Wiley Periodicals, Inc.
Ke Yang - One of the best experts on this subject based on the ideXlab platform.
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one step electrodeposition synthesis of bisphosphonate loaded Magnesium Implant a strategy to modulate drug release for osteoporotic fracture healing
Journal of Materials Science & Technology, 2021Co-Authors: Weidan Wang, Peng Wan, Lizhen Zheng, Ling Qin, Ke YangAbstract:Abstract Osteoporotic fracture with increase of aging population became an urgent orthopedic problem. Bisphosphonates were widely recommended as effective clinical treatment drugs. Combination of biodegradable Mg-based Implants and merits of bisphosphonates was suggested for osteoporotic fracture healing. Considering the mild and sustained drug release, a novel one-step electrodeposition synthesis of drug loaded coating was proposed in this study. In comparison to conventional soaking method, encapsulated zoledronate coating by one-step electrodeposition method could modulate drug release in first diffusion-controlled and later degradation-controlled manner. The in vitro cell response to zoledronate loaded coating showed enhanced proliferation and osteogenic differentiation of osteoblasts and no significant inhibition on osteoclasts, which could improve bone-forming and decrease bone resorption due to osteoporosis.
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In Vivo Study on Degradation Behavior and Histologic Response of Pure Magnesium in Muscles
Journal of Materials Science & Technology, 2017Co-Authors: Shanshan Chen, Ke Xu, Bingchun Zhang, Ke YangAbstract:When an orthopedics device is Implanted into bone injury site, it will contact the soft tissue (skeletal muscle, fascia, ligament etc.) except for bone. Magnesium based biodegradable metals are becoming an important research object in orthopedics due to their bioactivity to promote bone healing. In this study, pure Mg rods with and without chemical conversion coating were Implanted into the muscle tissue of rabbits. Implants and their surrounding tissues were taken out for weight loss measurement, cross-sectional scanning electron microscopy observation, elemental distribution analysis and histological examination. The results showed that the chemical conversion coating would increase the in vivo corrosion resistance of pure Mg and decrease the accumulation of calcium (Ca) and phosphorus (P) elements around the Implants. For the bare Magnesium Implant, both Ca and P contents in the surrounding tissues increased at the initial stage of Implantation and then decreased at 12 weeks Implantation, while for the Magnesium with chemical conversion coating, Ca and P contents in the surrounding tissues decreased with the Implantation time, but were not significant. The histological results demonstrated that there was no calcification in the muscle tissue with Implantation of Magnesium for up to 12 weeks. The chemical conversion coating not only increased the in vivo corrosion resistance of pure Mg, but also avoided the depositions of Ca and P in the surrounding tissues, meaning that pure Magnesium should be bio-safe when contacting with muscle tissues.
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in vivo evaluation of biodegradable Magnesium alloy bone Implant in the first 6 months Implantation
Journal of Biomedical Materials Research Part A, 2009Co-Authors: Erlin Zhang, Feng Pan, Ke YangAbstract:In vivo degradation of Magnesium alloy Implant, the bone response to the Magnesium, and the effect of the degradation of Magnesium on the blood composition and organs were investigated by using light microscopy and scanning electronic microscopy with energy dispersive spectrum. Magnesium alloy showed different degradation rates in the marrow channel and the cortical bone. More degradation of Magnesium Implant was observed in the marrow channel than in the cortical bone. New bone tissue formed around the Magnesium Implants after 6 weeks Implantation but no fibrous capsule was found. There existed two distinct layers separating the new bone tissue from the Magnesium Implant. On the Magnesium Implant side, crystalline Magnesium calcium phosphate formed on the surface of the Implant due to the reaction between the Implant and blood or body fluid. On the new bone tissue side was a 10-30-microm membrane comprising two distinct layers with many fibroblasts in the layer close to the new bone tissue. The new bone was in tight contact with the Implant through the membrane and phosphate layer due to the good osteoconductivity of the phosphate layer. After 10 and 26 weeks postImplantation, more new bone tissues as well as the membrane were found around the Implant. However, no apparent increase in the thickness of the membrane was observed with the increasing of the Implantation duration. Blood examination has shown that the degradation of the Magnesium Implant caused little change to blood composition but no disorder to liver or kidneys.
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in vivo corrosion behavior of mg mn zn alloy for bone Implant application
Journal of Biomedical Materials Research Part A, 2007Co-Authors: Erlin Zhang, Feng Pan, Ke YangAbstract:Magnesium alloy has been Implanted in rats to investigate the in vivo degradation behavior of Magnesium for bone Implant application. After 9 weeks postoperation, 100% Implants were fixed and no inflammation was observed. Histological analysis showed new bone was formed around Magnesium Implant and no difference was found in the histological microstructure of the new bone and the cortical bone. A degradation or reaction layer, which was mainly composed of Ca, P, O, and Mg, was formed on the surface of Magnesium alloy Implants. High Ca content in the degradation layer displayed that Magnesium could promote the deposition of Ca. Residual area calculation has showed that 10-17% Magnesium alloy Implant has been degraded in vivo. Compared with that of the controlled rats, no increase in serum Magnesium and no disorder of kidney were observed after 15 weeks postoperation. After 18 weeks postoperation, 100% Magnesium Implants were fixed and no inflammation was observed. About 54% Magnesium Implant has degraded in vivo. Element analysis showed that Zn and Mn in Mg-Mn-Zn alloy distributed homogeneously in the residual Magnesium Implant, the degradation layer, and the surrounding bone tissue after 18 weeks Implantation, indicating that Zn and Mn elements were easily absorbed by bioenvironment. (C) 2007 Wiley Periodicals, Inc.
Ying Zhao - One of the best experts on this subject based on the ideXlab platform.
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a functionalized tio2 mg2tio4 nano layer on biodegradable Magnesium Implant enables superior bone Implant integration and bacterial disinfection
Biomaterials, 2019Co-Authors: Kenneth M C Cheung, Yufeng Zheng, Ying Zhao, Paul K. Chu, Zhengjie Lin, Luning Wang, Haobo Pan, Xuanyong Liu, Takman WongAbstract:Abstract Rapid corrosion of biodegradable Magnesium alloys under in vivo condition is a major concern for clinical applications. Inspired by the stability and biocompatibility of titanium oxide (TiO2) passive layer, a functionalized TiO2/Mg2TiO4 nano-layer has been constructed on the surface of WE43 Magnesium Implant by using plasma ion immersion Implantation (PIII) technique. The customized nano-layer not only enhances corrosion resistance of Mg substrates significantly, but also elevates the osteoblastic differentiation capability in vitro due to the controlled release of Magnesium ions. In the animal study, the increase of new bone formation adjacent to the PIII-treated Magnesium substrate is 175% higher at post-operation 12 weeks, whereas the growth of new bone on titanium control and untreated Magnesium substrate are only 97% and 29%, respectively. In addition, its Young's modulus can be restored to about 82% as compared with the surrounding matured bone. Furthermore, this specific TiO2/Mg2TiO4 layer even exhibits photoactive bacteria disinfection capability when irradiated by ultraviolet light which is attributed to the intracellular reactive oxygen species (ROS) production. With all these constructive observations, it is believed that the TiO2/Mg2TiO4 nano-layer on Magnesium Implants can significantly promote new bone formation and suppress bacterial infection, while the degradation behavior can be controlled simultaneously.
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a surface engineered multifunctional tio2 based nano layer simultaneously elevates the corrosion resistance osteoconductivity and antimicrobial property of a Magnesium alloy
Acta Biomaterialia, 2019Co-Authors: Shuilin Wu, Kenneth M C Cheung, Yufeng Zheng, Ying Zhao, Shi Qian, Kelvin W K YeungAbstract:Abstract Magnesium biometals exhibit great potentials for orthopeadic applications owing to their biodegradability, bioactive effects and satisfactory mechanical properties. However, rapid corrosion of Mg Implants in vivo combined with large amount of hydrogen gas evolution is harmful to bone healing process which seriously confines their clinical applications. Enlightened by the superior biocompatibility and corrosion resistance of passive titanium oxide layer automatically formed on titanium alloy, we employ the Ti and O dual plasma ion immersion Implantation (PIII) technique to construct a multifunctional TiO2 based nano-layer on ZK60 Magnesium substrates for enhanced corrosion resistance, osteoconductivity and antimicrobial activity. The constructed nano-layer (TiO2/MgO) can effectively suppress degradation rate of ZK60 substrates in vitro and still maintain 94% Implant volume after post-surgery eight weeks. In animal study, a large amount of bony tissue with increased bone mineral density and trabecular thickness is formed around the PIII treated group in post-operation eight weeks. Moreover, the newly formed bone in the PIII treated group is well mineralized and its mechanical property almost restores to the level of that of surrounding mature bone. Surprisingly, a remarkable killing ratio of 99.31% against S. aureus can be found on the PIII treated sample under ultra-violet (UV) irradiation which mainly attributes to the oxidative stress induced by the reactive oxygen species (ROS). We believe that this multifunctional TiO2 based nano-layer not only controls the degradation of Magnesium Implant, but also regulates its Implant-to-bone integration effectively. Statement of significance Rapid corrosion of Magnesium Implants is the major issue for orthopaedic applications. Inspired by the biocompatibility and corrosion resistance of passive titanium oxide layer automatically formed on titanium alloy, we construct a multifunctional TiO2/MgO nanolayer on Magnesium substrates to simultaneously achieve superior corrosion resistance, satisfactory osteoconductivity in rat intramedullary bone defect model and excellent antimicrobial activity against S. aureus under UV irradiation. The current findings suggest that the specific TiO2/MgO nano-layer on Magnesium surface can achieve the three objectives aforementioned and we believe this study can demonstrate the potential of biodegradable metals for future clinical applications.
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in vivo stimulation of bone formation by aluminum and oxygen plasma surface modified Magnesium Implants
Biomaterials, 2013Co-Authors: H M Wong, Vivia W Y Tam, Frankie Leung, Keith D K Luk, Kenneth M C Cheung, Yufeng Zheng, Ying Zhao, Paul K. Chu, Kelvi W K YeungAbstract:Abstract A newly developed Magnesium Implant is used to stimulate bone formation in vivo. The Magnesium Implant after undergoing dual aluminum and oxygen plasma Implantation is able to suppress rapid corrosion, leaching of Magnesium ions, as well as hydrogen gas release from the biodegradable alloy in simulated body fluid (SBF). No released aluminum is detected from the SBF extract and enhanced corrosion resistance properties are confirmed by electrochemical tests. In vitro studies reveal enhanced growth of GFP mouse osteoblasts on the aluminum oxide coated sample, but not on the untreated sample. In addition to that a small amount (50 ppm) of Magnesium ions can enhance osteogenic differentiation as reported previously, our present data show a low concentration of hydrogen can give rise to the same effect. To compare the bone volume change between the plasma-treated Magnesium Implant and untreated control, micro-computed tomography is performed and the plasma-treated Implant is found to induce significant new bone formation adjacent to the Implant from day 1 until the end of the animal study. On the contrary, bone loss is observed during the first week post-operation from the untreated Magnesium sample. Owing to the protection offered by the Al2O3 layer, the plasma-treated Implant degrades more slowly and the small amount of released Magnesium ions stimulate new bone formation locally as revealed by histological analyses. Scanning electron microscopy discloses that the Al2O3 layer at the bone-Implant interface is still present two months after Implantation. In addition, no inflammation or tissue necrosis is observed from both treated and untreated Implants. These promising results suggest that the plasma-treated Magnesium Implant can stimulate bone formation in vivo in a minimal invasive way and without causing post-operative complications.
Yufeng Zheng - One of the best experts on this subject based on the ideXlab platform.
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a functionalized tio2 mg2tio4 nano layer on biodegradable Magnesium Implant enables superior bone Implant integration and bacterial disinfection
Biomaterials, 2019Co-Authors: Kenneth M C Cheung, Yufeng Zheng, Ying Zhao, Paul K. Chu, Zhengjie Lin, Luning Wang, Haobo Pan, Xuanyong Liu, Takman WongAbstract:Abstract Rapid corrosion of biodegradable Magnesium alloys under in vivo condition is a major concern for clinical applications. Inspired by the stability and biocompatibility of titanium oxide (TiO2) passive layer, a functionalized TiO2/Mg2TiO4 nano-layer has been constructed on the surface of WE43 Magnesium Implant by using plasma ion immersion Implantation (PIII) technique. The customized nano-layer not only enhances corrosion resistance of Mg substrates significantly, but also elevates the osteoblastic differentiation capability in vitro due to the controlled release of Magnesium ions. In the animal study, the increase of new bone formation adjacent to the PIII-treated Magnesium substrate is 175% higher at post-operation 12 weeks, whereas the growth of new bone on titanium control and untreated Magnesium substrate are only 97% and 29%, respectively. In addition, its Young's modulus can be restored to about 82% as compared with the surrounding matured bone. Furthermore, this specific TiO2/Mg2TiO4 layer even exhibits photoactive bacteria disinfection capability when irradiated by ultraviolet light which is attributed to the intracellular reactive oxygen species (ROS) production. With all these constructive observations, it is believed that the TiO2/Mg2TiO4 nano-layer on Magnesium Implants can significantly promote new bone formation and suppress bacterial infection, while the degradation behavior can be controlled simultaneously.
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a surface engineered multifunctional tio2 based nano layer simultaneously elevates the corrosion resistance osteoconductivity and antimicrobial property of a Magnesium alloy
Acta Biomaterialia, 2019Co-Authors: Shuilin Wu, Kenneth M C Cheung, Yufeng Zheng, Ying Zhao, Shi Qian, Kelvin W K YeungAbstract:Abstract Magnesium biometals exhibit great potentials for orthopeadic applications owing to their biodegradability, bioactive effects and satisfactory mechanical properties. However, rapid corrosion of Mg Implants in vivo combined with large amount of hydrogen gas evolution is harmful to bone healing process which seriously confines their clinical applications. Enlightened by the superior biocompatibility and corrosion resistance of passive titanium oxide layer automatically formed on titanium alloy, we employ the Ti and O dual plasma ion immersion Implantation (PIII) technique to construct a multifunctional TiO2 based nano-layer on ZK60 Magnesium substrates for enhanced corrosion resistance, osteoconductivity and antimicrobial activity. The constructed nano-layer (TiO2/MgO) can effectively suppress degradation rate of ZK60 substrates in vitro and still maintain 94% Implant volume after post-surgery eight weeks. In animal study, a large amount of bony tissue with increased bone mineral density and trabecular thickness is formed around the PIII treated group in post-operation eight weeks. Moreover, the newly formed bone in the PIII treated group is well mineralized and its mechanical property almost restores to the level of that of surrounding mature bone. Surprisingly, a remarkable killing ratio of 99.31% against S. aureus can be found on the PIII treated sample under ultra-violet (UV) irradiation which mainly attributes to the oxidative stress induced by the reactive oxygen species (ROS). We believe that this multifunctional TiO2 based nano-layer not only controls the degradation of Magnesium Implant, but also regulates its Implant-to-bone integration effectively. Statement of significance Rapid corrosion of Magnesium Implants is the major issue for orthopaedic applications. Inspired by the biocompatibility and corrosion resistance of passive titanium oxide layer automatically formed on titanium alloy, we construct a multifunctional TiO2/MgO nanolayer on Magnesium substrates to simultaneously achieve superior corrosion resistance, satisfactory osteoconductivity in rat intramedullary bone defect model and excellent antimicrobial activity against S. aureus under UV irradiation. The current findings suggest that the specific TiO2/MgO nano-layer on Magnesium surface can achieve the three objectives aforementioned and we believe this study can demonstrate the potential of biodegradable metals for future clinical applications.
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in vivo stimulation of bone formation by aluminum and oxygen plasma surface modified Magnesium Implants
Biomaterials, 2013Co-Authors: H M Wong, Vivia W Y Tam, Frankie Leung, Keith D K Luk, Kenneth M C Cheung, Yufeng Zheng, Ying Zhao, Paul K. Chu, Kelvi W K YeungAbstract:Abstract A newly developed Magnesium Implant is used to stimulate bone formation in vivo. The Magnesium Implant after undergoing dual aluminum and oxygen plasma Implantation is able to suppress rapid corrosion, leaching of Magnesium ions, as well as hydrogen gas release from the biodegradable alloy in simulated body fluid (SBF). No released aluminum is detected from the SBF extract and enhanced corrosion resistance properties are confirmed by electrochemical tests. In vitro studies reveal enhanced growth of GFP mouse osteoblasts on the aluminum oxide coated sample, but not on the untreated sample. In addition to that a small amount (50 ppm) of Magnesium ions can enhance osteogenic differentiation as reported previously, our present data show a low concentration of hydrogen can give rise to the same effect. To compare the bone volume change between the plasma-treated Magnesium Implant and untreated control, micro-computed tomography is performed and the plasma-treated Implant is found to induce significant new bone formation adjacent to the Implant from day 1 until the end of the animal study. On the contrary, bone loss is observed during the first week post-operation from the untreated Magnesium sample. Owing to the protection offered by the Al2O3 layer, the plasma-treated Implant degrades more slowly and the small amount of released Magnesium ions stimulate new bone formation locally as revealed by histological analyses. Scanning electron microscopy discloses that the Al2O3 layer at the bone-Implant interface is still present two months after Implantation. In addition, no inflammation or tissue necrosis is observed from both treated and untreated Implants. These promising results suggest that the plasma-treated Magnesium Implant can stimulate bone formation in vivo in a minimal invasive way and without causing post-operative complications.
Kenneth M C Cheung - One of the best experts on this subject based on the ideXlab platform.
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a functionalized tio2 mg2tio4 nano layer on biodegradable Magnesium Implant enables superior bone Implant integration and bacterial disinfection
Biomaterials, 2019Co-Authors: Kenneth M C Cheung, Yufeng Zheng, Ying Zhao, Paul K. Chu, Zhengjie Lin, Luning Wang, Haobo Pan, Xuanyong Liu, Takman WongAbstract:Abstract Rapid corrosion of biodegradable Magnesium alloys under in vivo condition is a major concern for clinical applications. Inspired by the stability and biocompatibility of titanium oxide (TiO2) passive layer, a functionalized TiO2/Mg2TiO4 nano-layer has been constructed on the surface of WE43 Magnesium Implant by using plasma ion immersion Implantation (PIII) technique. The customized nano-layer not only enhances corrosion resistance of Mg substrates significantly, but also elevates the osteoblastic differentiation capability in vitro due to the controlled release of Magnesium ions. In the animal study, the increase of new bone formation adjacent to the PIII-treated Magnesium substrate is 175% higher at post-operation 12 weeks, whereas the growth of new bone on titanium control and untreated Magnesium substrate are only 97% and 29%, respectively. In addition, its Young's modulus can be restored to about 82% as compared with the surrounding matured bone. Furthermore, this specific TiO2/Mg2TiO4 layer even exhibits photoactive bacteria disinfection capability when irradiated by ultraviolet light which is attributed to the intracellular reactive oxygen species (ROS) production. With all these constructive observations, it is believed that the TiO2/Mg2TiO4 nano-layer on Magnesium Implants can significantly promote new bone formation and suppress bacterial infection, while the degradation behavior can be controlled simultaneously.
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a surface engineered multifunctional tio2 based nano layer simultaneously elevates the corrosion resistance osteoconductivity and antimicrobial property of a Magnesium alloy
Acta Biomaterialia, 2019Co-Authors: Shuilin Wu, Kenneth M C Cheung, Yufeng Zheng, Ying Zhao, Shi Qian, Kelvin W K YeungAbstract:Abstract Magnesium biometals exhibit great potentials for orthopeadic applications owing to their biodegradability, bioactive effects and satisfactory mechanical properties. However, rapid corrosion of Mg Implants in vivo combined with large amount of hydrogen gas evolution is harmful to bone healing process which seriously confines their clinical applications. Enlightened by the superior biocompatibility and corrosion resistance of passive titanium oxide layer automatically formed on titanium alloy, we employ the Ti and O dual plasma ion immersion Implantation (PIII) technique to construct a multifunctional TiO2 based nano-layer on ZK60 Magnesium substrates for enhanced corrosion resistance, osteoconductivity and antimicrobial activity. The constructed nano-layer (TiO2/MgO) can effectively suppress degradation rate of ZK60 substrates in vitro and still maintain 94% Implant volume after post-surgery eight weeks. In animal study, a large amount of bony tissue with increased bone mineral density and trabecular thickness is formed around the PIII treated group in post-operation eight weeks. Moreover, the newly formed bone in the PIII treated group is well mineralized and its mechanical property almost restores to the level of that of surrounding mature bone. Surprisingly, a remarkable killing ratio of 99.31% against S. aureus can be found on the PIII treated sample under ultra-violet (UV) irradiation which mainly attributes to the oxidative stress induced by the reactive oxygen species (ROS). We believe that this multifunctional TiO2 based nano-layer not only controls the degradation of Magnesium Implant, but also regulates its Implant-to-bone integration effectively. Statement of significance Rapid corrosion of Magnesium Implants is the major issue for orthopaedic applications. Inspired by the biocompatibility and corrosion resistance of passive titanium oxide layer automatically formed on titanium alloy, we construct a multifunctional TiO2/MgO nanolayer on Magnesium substrates to simultaneously achieve superior corrosion resistance, satisfactory osteoconductivity in rat intramedullary bone defect model and excellent antimicrobial activity against S. aureus under UV irradiation. The current findings suggest that the specific TiO2/MgO nano-layer on Magnesium surface can achieve the three objectives aforementioned and we believe this study can demonstrate the potential of biodegradable metals for future clinical applications.
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in vivo stimulation of bone formation by aluminum and oxygen plasma surface modified Magnesium Implants
Biomaterials, 2013Co-Authors: H M Wong, Vivia W Y Tam, Frankie Leung, Keith D K Luk, Kenneth M C Cheung, Yufeng Zheng, Ying Zhao, Paul K. Chu, Kelvi W K YeungAbstract:Abstract A newly developed Magnesium Implant is used to stimulate bone formation in vivo. The Magnesium Implant after undergoing dual aluminum and oxygen plasma Implantation is able to suppress rapid corrosion, leaching of Magnesium ions, as well as hydrogen gas release from the biodegradable alloy in simulated body fluid (SBF). No released aluminum is detected from the SBF extract and enhanced corrosion resistance properties are confirmed by electrochemical tests. In vitro studies reveal enhanced growth of GFP mouse osteoblasts on the aluminum oxide coated sample, but not on the untreated sample. In addition to that a small amount (50 ppm) of Magnesium ions can enhance osteogenic differentiation as reported previously, our present data show a low concentration of hydrogen can give rise to the same effect. To compare the bone volume change between the plasma-treated Magnesium Implant and untreated control, micro-computed tomography is performed and the plasma-treated Implant is found to induce significant new bone formation adjacent to the Implant from day 1 until the end of the animal study. On the contrary, bone loss is observed during the first week post-operation from the untreated Magnesium sample. Owing to the protection offered by the Al2O3 layer, the plasma-treated Implant degrades more slowly and the small amount of released Magnesium ions stimulate new bone formation locally as revealed by histological analyses. Scanning electron microscopy discloses that the Al2O3 layer at the bone-Implant interface is still present two months after Implantation. In addition, no inflammation or tissue necrosis is observed from both treated and untreated Implants. These promising results suggest that the plasma-treated Magnesium Implant can stimulate bone formation in vivo in a minimal invasive way and without causing post-operative complications.
