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Hyoun-ee Kim - One of the best experts on this subject based on the ideXlab platform.
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Dense nanostructured Hydroxyapatite Coating on titanium by aerosol deposition
Journal of the American Ceramic Society, 2009Co-Authors: Byung Dong Hahn, Jungho Ryu, Chan Park, Woon Ha Yoon, Jong Jin Choi, Dong Soo Park, Ki Hoon Kim, Hyoun-ee KimAbstract:In order to improve biocompatibility of Ti metal substrates, 1-μm-thick nanostructured Hydroxyapatite (HAp) Coatings were deposited on the substrates through aerosol deposition, which sprays HAp powder with an average particle size of 3.2 μm at room temperature in vacuum. The original HAp particles were fractured into nanoscale fragments to form highly dense Coating during the deposition process. Density of the HAp Coating was 98.5% theoretical density (TD). Transmission electron microscopy observation revealed that the as-deposited Coating consisted of HAp crystallites with average grain size of 16.2 nm and amorphous phase. Tensile adhesion strength between the Coating and the substrate was 30.5±1.2 MPa. Annealing up to 500°C in air increased crystallinity and grain size in the Coating without any delamination or crack according to X-ray diffraction analysis and electron microscopy. MTS assay and alkaline phosphatase activity measurements with MC3T3-E1 preosteoblast cell revealed that the biocompatibility was greatly improved by postdeposition heat treatment at 400°C in air due to well-crystallized HAp with average grain size of 29.3 nm. However, further heat treatment at 500°C deteriorated biocompatibility due to rapid growth of HAp grains to average size of 99 nm. Cross section of the Coating on a commercially available Ti dental implant revealed full coverage of the surface with HAp.
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Hydroxyapatite Coating on titanium substrate with titania buffer layer processed by sol gel method
Biomaterials, 2004Co-Authors: Haewon Kim, Young Hag Koh, Sook Lee, Hyoun-ee KimAbstract:Hydroxyapatite (HA) was coated onto a titanium (Ti) substrate with the insertion of a titania (TiO2) buffer layer by the sol-gel method. The HA layer was employed to enhance the bioactivity and osteoconductivity of the Ti substrate, and the TiO2 buffer layer was inserted to improve the bonding strength between the HA layer and Ti substrate, as well as to prevent the corrosion of the Ti substrate. The HA layer coated over the TiO2 showed a typical apatite phase at 400 degrees C and the phase intensity increased above 450 degrees C. The sol-gel derived HA and TiO2 films, with thicknesses of approximately 800 and 200 nm, respectively, adhered tightly to each other and to the Ti substrate. The bonding strength of the HA/TiO2 double layer Coating on Ti was markedly improved when compared to that of the HA single Coating on Ti. The highest strength of the double layer Coating was 55 MPa after heat treatment at 500 degrees C. The improvement in bonding strength with the insertion of TiO2 was attributed to the resulting enhanced chemical affinity of TiO2 toward the HA layer, as well as toward the Ti substrate. Human osteoblast-like cells, cultured on the HA/TiO2 Coating surface, proliferated in a similar manner to those on the TiO2 single Coating and on the pure Ti surfaces. However, the alkaline phosphatase activity of the cells on the HA/TiO2 double layer was expressed to a higher degree than that on the TiO2 single Coating and pure Ti surfaces. The corrosion resistance of Ti was improved by the presence of the TiO2 Coating, as confirmed by a potentiodynamic polarization test.
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ion beam assisted deposition ibad of Hydroxyapatite Coating layer on ti based metal substrate
Biomaterials, 2000Co-Authors: Jaeman Choi, Hyoun-ee Kim, Inseop LeeAbstract:A Hydroxyapatite layer was formed on the surface of a Ti-based alloy by ion-beam-assisted deposition. The deposition methodology comprised of an electron beam vaporizing a pure Hydroxyapatite target, while an Ar ion beam was focused on the metal substrate to assist deposition. All deposited layers were amorphous, regardless of the current level of the ion beam. The bond strength between the layer and the substrate increased steadily with increasing current, while the dissolution rate in a physiological saline solution decreased remarkably. These improvements were attributed to an increase in the Ca/P ratio of the layer. Without ion beam assistance, the Ca/P ratio was much lower than the stoichiometric HAp (Ca/P = 1.67). With ion-beam assistance, the Ca/P ratio of the layer increased presumably due to the high sputtering rate of P compared to that of Ca from the layer being coated.
Keyvan Raeissi - One of the best experts on this subject based on the ideXlab platform.
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electrophoretic deposition of nanostructured Hydroxyapatite Coating on az91 magnesium alloy implants with different surface treatments
Applied Surface Science, 2013Co-Authors: Ramin Rojaee, M H Fathi, Keyvan RaeissiAbstract:Abstract Bio-absorbable magnesium (Mg) based alloys have been introduced as innovative orthopedic implants during recent years. It has been specified that rapid degradation of Mg based alloys in physiological environment should be restrained in order to be utilized in orthopedic trauma fixation and vascular intervention. In this developing field of healthcare materials, micro-arc oxidation (MAO), and MgF2 conversion Coating were exploited as surface pre-treatment of AZ91 magnesium alloy to generate a nanostructured Hydroxyapatite (n-HAp) Coating via electrophoretic deposition (EPD) method. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM) techniques were used to characterize the obtained powder and Coatings. The potentiodynamic polarization tests were carried out to evaluate the corrosion behavior of the coated and uncoated specimens, and in vitro bioactivity evaluation were performed in simulated body fluid. Results revealed that the MAO/n-HAp coated AZ91 Mg alloy samples with a rough topography and lower corrosion current density leads to a lower Mg degradation rate accompanied by high bioactivity.
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controlling the degradation rate of az91 magnesium alloy via sol gel derived nanostructured Hydroxyapatite Coating
Materials Science and Engineering: C, 2013Co-Authors: Ramin Rojaee, M H Fathi, Keyvan RaeissiAbstract:Abstract Magnesium (Mg) alloys have been introduced as new generation of biodegradable orthopedic materials in recent years since it has been proved that Mg is one of the main minerals required for osseous tissue revival. The main goal of the present study was to establish a desired harmony between the necessities of orthopedic patient body to Mg2 + ions and degradation rate of the Mg based implants as a new class of biodegradable/bioresorbable materials. This prospect was followed by providing a sol–gel derived nanostructured Hydroxyapatite (n-HAp) Coating on AZ91 alloy using dip Coating technique. Phase structural analysis, morphology study, microstructure characterization, and functional group identification were performed using X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. The prepared samples were immersed in simulated body fluid in order to study the formation of apatite-like precipitations, barricade properties of the n-HAp Coating, and to estimate the dosage of released Mg2 + ions within a specified and limited time of implantation. Electrochemical polarization tests were carried out to evaluate and compare the corrosion behavior of the n-HAp coated and uncoated samples. The changes of the in vitro pH values were also evaluated. Results posed the noticeable capability of n-HAp Coating on stabilizing alkalization behavior and improving the corrosion resistance of AZ91 alloy. It was concluded that n-HAp coated AZ91 alloy could be a good candidate as a type of biodegradable implant material for biomedical applications.
M H Fathi - One of the best experts on this subject based on the ideXlab platform.
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electrophoretic deposition of nanostructured Hydroxyapatite Coating on az91 magnesium alloy implants with different surface treatments
Applied Surface Science, 2013Co-Authors: Ramin Rojaee, M H Fathi, Keyvan RaeissiAbstract:Abstract Bio-absorbable magnesium (Mg) based alloys have been introduced as innovative orthopedic implants during recent years. It has been specified that rapid degradation of Mg based alloys in physiological environment should be restrained in order to be utilized in orthopedic trauma fixation and vascular intervention. In this developing field of healthcare materials, micro-arc oxidation (MAO), and MgF2 conversion Coating were exploited as surface pre-treatment of AZ91 magnesium alloy to generate a nanostructured Hydroxyapatite (n-HAp) Coating via electrophoretic deposition (EPD) method. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM) techniques were used to characterize the obtained powder and Coatings. The potentiodynamic polarization tests were carried out to evaluate the corrosion behavior of the coated and uncoated specimens, and in vitro bioactivity evaluation were performed in simulated body fluid. Results revealed that the MAO/n-HAp coated AZ91 Mg alloy samples with a rough topography and lower corrosion current density leads to a lower Mg degradation rate accompanied by high bioactivity.
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controlling the degradation rate of az91 magnesium alloy via sol gel derived nanostructured Hydroxyapatite Coating
Materials Science and Engineering: C, 2013Co-Authors: Ramin Rojaee, M H Fathi, Keyvan RaeissiAbstract:Abstract Magnesium (Mg) alloys have been introduced as new generation of biodegradable orthopedic materials in recent years since it has been proved that Mg is one of the main minerals required for osseous tissue revival. The main goal of the present study was to establish a desired harmony between the necessities of orthopedic patient body to Mg2 + ions and degradation rate of the Mg based implants as a new class of biodegradable/bioresorbable materials. This prospect was followed by providing a sol–gel derived nanostructured Hydroxyapatite (n-HAp) Coating on AZ91 alloy using dip Coating technique. Phase structural analysis, morphology study, microstructure characterization, and functional group identification were performed using X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. The prepared samples were immersed in simulated body fluid in order to study the formation of apatite-like precipitations, barricade properties of the n-HAp Coating, and to estimate the dosage of released Mg2 + ions within a specified and limited time of implantation. Electrochemical polarization tests were carried out to evaluate and compare the corrosion behavior of the n-HAp coated and uncoated samples. The changes of the in vitro pH values were also evaluated. Results posed the noticeable capability of n-HAp Coating on stabilizing alkalization behavior and improving the corrosion resistance of AZ91 alloy. It was concluded that n-HAp coated AZ91 alloy could be a good candidate as a type of biodegradable implant material for biomedical applications.
D Gopi - One of the best experts on this subject based on the ideXlab platform.
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electrodeposition of cerium substituted Hydroxyapatite Coating on passivated surgical grade stainless steel for biomedical application
2015Co-Authors: Saravanan Sathishkumar, L Kavitha, A Karthika, D GopiAbstract:Surgical grade stainless steel (316L SS) is mostly used in orthopedic implants due to its good mechanical properties, corrosion resistance and good biocompatibility. Though it possesses advantages, the surface of stainless steel is prone to release metal ions in the physiological medium. For this reason, it is important tointroduce bioceramic Coatings on the metallic surface to improve the biocompatibility and corrosion resistance. The present work is dealt with successful development of cerium substituted Hydroxyapatite (Ce-HAP) on borate passivated 316L SS. The Coatings were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX). The electrochemical characterization such as using potentiodynamic cyclic polarization and electrochemical impedance spectroscopic techniques of Ce-HAP Coating on the passivated 316L SS in Ringer's solution demonstrated the enhanced anti-corrosion performance of Ce-HAP Coating. The antimicrobial performance was studied for the obtained Coatings against the pathogenic bacterial strains S. aureusand E. coli. Thus, the Ce- HAP Coating on the passivated 316L SS can play a significant role in the biomedical applications.
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enhanced corrosion resistance of strontium Hydroxyapatite Coating on electron beam treated surgical grade stainless steel
Applied Surface Science, 2013Co-Authors: D Gopi, S Ramya, D Rajeswari, L Kavitha, M Sekar, R Pramod, Jishnu Dwivedi, R RamaseshanAbstract:Abstract The surface of 316L stainless steel (316L SS) is irradiated by high energy low current DC electron beam (HELCDEB) with energy of 500 keV and beam current of 1.5 mA followed by the electrodeposition of strontium Hydroxyapatite (Sr-HAp) to enhance its corrosion resistance in physiological fluid. The Coatings were characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and High resolution scanning electron microscopy (HRSEM). The Sr-HAp Coating on HELCDEB treated 316L SS exhibits micro-flower structure. Electrochemical results show that the Sr-HAp Coating on HELCDEB treated 316L SS possesses maximum corrosion resistance in Ringer's solution.
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corrosion protection performance of porous strontium Hydroxyapatite Coating on polypyrrole coated 316l stainless steel
Colloids and Surfaces B: Biointerfaces, 2013Co-Authors: D Gopi, S Ramya, D Rajeswari, L KavithaAbstract:Polypyrrole/strontium Hydroxyapatite bilayer Coatings were achieved on 316L stainless steel (316L SS) by the electropolymerisation of pyrrole from sodium salicylate solution followed by the electrodeposition of porous strontium Hydroxyapatite. The formation and the morphology of the bilayer Coatings were characterised by Fourier transform infrared spectroscopy (FT-IR) and high resolution scanning electron microscopy (HRSEM), respectively. The corrosion resistance of the coated 316L SS specimens was investigated in Ringer's solution by electrochemical techniques and the results were substantiated with inductively coupled plasma atomic emission spectrometry (ICP-AES). The passive film underneath the polypyrrole layer is effective in protecting 316L SS against corrosion in Ringer's solution. Moreover, we believe that the top porous strontium Hydroxyapatite layer can provide potential bioactivity to the 316L SS.
L Kavitha - One of the best experts on this subject based on the ideXlab platform.
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electrodeposition of cerium substituted Hydroxyapatite Coating on passivated surgical grade stainless steel for biomedical application
2015Co-Authors: Saravanan Sathishkumar, L Kavitha, A Karthika, D GopiAbstract:Surgical grade stainless steel (316L SS) is mostly used in orthopedic implants due to its good mechanical properties, corrosion resistance and good biocompatibility. Though it possesses advantages, the surface of stainless steel is prone to release metal ions in the physiological medium. For this reason, it is important tointroduce bioceramic Coatings on the metallic surface to improve the biocompatibility and corrosion resistance. The present work is dealt with successful development of cerium substituted Hydroxyapatite (Ce-HAP) on borate passivated 316L SS. The Coatings were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX). The electrochemical characterization such as using potentiodynamic cyclic polarization and electrochemical impedance spectroscopic techniques of Ce-HAP Coating on the passivated 316L SS in Ringer's solution demonstrated the enhanced anti-corrosion performance of Ce-HAP Coating. The antimicrobial performance was studied for the obtained Coatings against the pathogenic bacterial strains S. aureusand E. coli. Thus, the Ce- HAP Coating on the passivated 316L SS can play a significant role in the biomedical applications.
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enhanced corrosion resistance of strontium Hydroxyapatite Coating on electron beam treated surgical grade stainless steel
Applied Surface Science, 2013Co-Authors: D Gopi, S Ramya, D Rajeswari, L Kavitha, M Sekar, R Pramod, Jishnu Dwivedi, R RamaseshanAbstract:Abstract The surface of 316L stainless steel (316L SS) is irradiated by high energy low current DC electron beam (HELCDEB) with energy of 500 keV and beam current of 1.5 mA followed by the electrodeposition of strontium Hydroxyapatite (Sr-HAp) to enhance its corrosion resistance in physiological fluid. The Coatings were characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and High resolution scanning electron microscopy (HRSEM). The Sr-HAp Coating on HELCDEB treated 316L SS exhibits micro-flower structure. Electrochemical results show that the Sr-HAp Coating on HELCDEB treated 316L SS possesses maximum corrosion resistance in Ringer's solution.
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corrosion protection performance of porous strontium Hydroxyapatite Coating on polypyrrole coated 316l stainless steel
Colloids and Surfaces B: Biointerfaces, 2013Co-Authors: D Gopi, S Ramya, D Rajeswari, L KavithaAbstract:Polypyrrole/strontium Hydroxyapatite bilayer Coatings were achieved on 316L stainless steel (316L SS) by the electropolymerisation of pyrrole from sodium salicylate solution followed by the electrodeposition of porous strontium Hydroxyapatite. The formation and the morphology of the bilayer Coatings were characterised by Fourier transform infrared spectroscopy (FT-IR) and high resolution scanning electron microscopy (HRSEM), respectively. The corrosion resistance of the coated 316L SS specimens was investigated in Ringer's solution by electrochemical techniques and the results were substantiated with inductively coupled plasma atomic emission spectrometry (ICP-AES). The passive film underneath the polypyrrole layer is effective in protecting 316L SS against corrosion in Ringer's solution. Moreover, we believe that the top porous strontium Hydroxyapatite layer can provide potential bioactivity to the 316L SS.
