PRECIPITATION CONTROL AND MECHANICAL PROPERTY OF CALCIUM PHOSPHATE–COATED AZ31B ALLOY FOR BIOMEDICAL APPLICATION

2011 ◽  
Vol 23 (03) ◽  
pp. 193-203 ◽  
Author(s):  
Qiang Wang ◽  
Lili Tan ◽  
Qiang Zhang ◽  
Jianhong Qiu ◽  
Ke Yang
Keyword(s):  
Magnesium Alloy ◽  
Calcium Phosphate ◽  
Electrochemical Impedance ◽  
Biomedical Application ◽  
Early Stage ◽  
Calcium Phosphates ◽  
Chemical Deposition ◽  
Biological Properties ◽  
Calcium Phosphate Coating ◽  
Az31b Alloy

Surface modification is believed to be an effective way to control the biodegradation rate of magnesium alloys and improve their biological properties. In the present work, a calcium phosphate (Ca-P) coating was prepared on the AZ31B magnesium alloy by a chemical deposition method to integrate the mechanical advantages of the magnesium substrate and the good bioactivity of the ceramic coating. It was shown that the coating was mainly composed of magnesium and calcium phosphates. Scanning electron microscope coupled with the energy dispersive spectrum analyses showed that rough and crystallined Ca-P coatings with different Ca/P ratios and thickness were formed on the alloy by variation of deposition time. The corrosion resistance of AZ31B alloy was significantly improved by the Ca-P coating. Electrochemical impedance spectroscopy test was used to illustrate the reaction process of Ca-P coating on the alloy. Upon the above results, Ca-P formation mechanism on the AZ31B alloy was proposed. The heterogeneous nucleation and growth of the calcium phosphate coating may be catalyzed by the anodic dissolution of the magnesium alloy substrate in the early stage of deposition, and the deposition coating is mainly composed of the magnesium phosphate. Then calcium phosphate deposition on the alloy becomes dominant with the increase of time. Tensile test in simulated body environment results showed that the time of fracture and ultimate tensile strength for the coated AZ31B Mg alloy were higher than those of the uncoated, which is beneficial in supporting fractured bone for a longer time.

Hydrothermal Growth of Nano-Hydroxyapatite Coating Formed on Fluorinated Magnesium Alloy and Its Corrosion Behaviour

2021 ◽  
Vol 13 (1) ◽  
pp. 10-19
Author(s):  
Chun-Yan Zhang ◽  
Hao-Lan Fang ◽  
Xin-Peng Liu ◽  
Fan-Cheng Meng ◽  
Zhong-Qing Tian ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Calcium Phosphate ◽  
Hydrothermal Treatment ◽  
Treatment Time ◽  
Electrochemical Impedance ◽  
Hydrothermal Growth ◽  
Crystal Phase ◽  
Calcium Phosphate Coating ◽  
Phosphate Coating ◽  
Ha Coating

In order to explore the hydrothermal growth mechanism of hydroxyapatite (HA) coating on fluorinated magnesium alloy, the changes of morphology, composition and crystal phase of the calcium phosphate coating during the hydrothermal treatment were studied. And the change of electrochemical impedance spectroscopy (EIS) of the coating specimen of different hydrothermal treatment time was discussed to further understanding the change of the coating structure. The results demonstrated that calcium phosphate could rapidly nucleate on fluorinated AZ31 magnesium alloy. The crystal phase of calcium phosphate coating was mainly octacalcium phosphate (OCP) at the early stage of hydrothermal treatment. Then the content of OCP decreased and the content of HA increased with hydrothermal time. The coating consisted of only HA after hydrothermal treatment for about 4h. The HA coating composed of rod-like crystals exhibited an obvious double layer structure. The rod-like crystals of inner layer arranged into dense bundles and the rod-like crystals of outer layer arranged into loose chrysanthemum-like clusters. Fluoride conversion layer acted as an intermediate transition layer to connect magnesium alloy and HA coating into a whole. The results of immersion test in simulated body fluid demonstrated that HA crystals dissolved slowly. No peeling occurred of HA coating during the 12 days' immersion. Pitting corrosion was still the mainly corrosion mode of magnesium alloy substrate due to the electrolyte infiltration during the immersion.

Corrosion Protection of Nano-biphasic Calcium Phosphate Coating on Titanium Substrate

2020 ◽  
Vol 16 (5) ◽  
pp. 779-792
Author(s):  
Ahlam M. Fathi ◽  
Howida S. Mandour ◽  
Hanaa K. Abd El-Hamid
Keyword(s):  
Calcium Phosphate ◽  
Simulated Body Fluid ◽  
Body Fluid ◽  
Biphasic Calcium Phosphate ◽  
Titanium Surface ◽  
Electrochemical Impedance ◽  
Calcium Phosphates ◽  
Diffusion Method ◽  
Calcium Phosphate Coating ◽  
Chemical Compositions

Background: Increasing the bioactivity of metallic implants is necessary for biomaterial applications where hydroxyapatite (HA) is used as a surface coating. In industry, HA is currently coated by plasma spraying, but this technique has a high cost and produces coating with short-term stability. Objectives: In the present study, electrophoretic deposition (EPD) was used to deposit nano-biphasic calcium phosphate compound (β-tri-calcium phosphate (β-TCP) /hydroxyapatite (HA)) bio-ceramics on the titanium surface. The microstructural, chemical compositions and bioactivity of the β- TCP/HA coatings were studied in a simulated body fluid solution (SBF). Methods: Scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR) were used. Additionally, the antibacterial effect was studied by the agar diffusion method. The corrosion behavior of the β-TCP/HA coating on titanium surface (Ti) in the SBF solution at 37oC was investigated by means of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests. Results: The Ti surface modification increased its biocompatibility and corrosion resistance in the simulated body fluid. The antibacterial inhibition activity of the β-TCP/HA bio-ceramic was enhanced by electroless silver deposition. The enhanced properties could be attributed to the use of nano-sized biphasic calcium phosphates in a low-temperature EPD process. Conclusions: The β-TCP/HA and β-TCP/HA/Ag coatings well protect Ti from the corrosion in SBF and endow Ti with biocompatibility. The β-4-TCP/HA/Ag/Ti substrate shows good antibacterial activity.

Characterization of Calcium Phosphate with an Anodic TiO2 Nanotube Layer on Titanium Screw for Biomedical Application

2014 ◽  
Vol 852 ◽  
pp. 251-255
Author(s):  
Ya Jing Yan ◽  
Yong Huang ◽  
Qiong Qiong Ding ◽  
Xiao Feng Pang
Keyword(s):  
Calcium Phosphate ◽  
Biomedical Application ◽  
Calcium Phosphates ◽  
Alkaline Treatment ◽  
Calcium Phosphate Coating ◽  
X Ray Diffraction ◽  
Titanium Screw ◽  
Phosphate Coatings ◽  
Titanium Screws ◽  
Calcium Phosphate Coatings

The present paper reports a novel solution to develop a calcium phosphates (CaPs) coating with an anodic nanotubular TiO2layer on titanium screw by electrochemical disposition (ECD). The elemental composition of coatings was examined by energy dispersive spectroscopy (EDS), the surface mopholoy was characterized with scanning electron microscopy (SEM), and the functional groups and crystalline phase were analyzed using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Furthermore, the bioactivity was tested by immersion in simulated body fluid (SBF) for 7 days. The results showed that a nanotubular TiO2layer was established which has about 100 mm diameter and the calcium phosphate coatings have higher bioactivity and porosity compared with uncoated titanium screws, which make the coating more conductive to cell adhesion. Using alkaline treatment, the calcium phosphate coating could transform into hydroxyapatite (HAp), making the coating closer to the biological complement. This provides a valuable tool for biomedical applications.

Growth of Calcium Phosphate Coating on Ti-7.5Mo Alloy after Anodic Oxidation

2013 ◽  
Vol 334-335 ◽  
pp. 297-302 ◽  
Author(s):  
A.L.A. Escada ◽  
João Paulo Barros Machado ◽  
Roberto Zenhei Nakazato ◽  
Ana Paula Rosifini Alves Claro
Keyword(s):  
Calcium Phosphate ◽  
Simulated Body Fluid ◽  
Body Fluid ◽  
Calcium Phosphates ◽  
Sodium Titanate ◽  
Ammonium Fluoride ◽  
Biological Properties ◽  
Calcium Phosphate Coating ◽  
Phosphate Coating

Titanium and its alloys are widely used as biomaterials due to their mechanical, chemical and biological properties. To enhance the biocompatibility of titanium alloys, various surface treatments have been proposed. In particular, the formation of titanium oxide nanotubes layers has been extensively examined. Among the various materials for implants, calcium phosphates and hydroxyapatite are widely used clinically. In this work, titanium nanotubes were fabricated on the surface of Ti-7.5Mo alloy by anodization. The samples were anodized for 20 V in an electrolyte containing glycerol in combination with ammonium fluoride (NH4F, 0.25%), and the anodization time was 24 h. After being anodized, specimens were heat treated at 450 °C and 600°C for 1 h to crystallize the amorphous TiO2 nanotubes and then treated with NaOH solution to make them bioactive, to induce growth of calcium phosphate in a simulated body fluid. Surface morphology and coating chemistry were obtained respectively using, field-emission scanning electron microscopy (FEG-SEM), AFM and X-ray diffraction (XRD). It was shown that the presence of titanium nanotubes induces the growth of a sodium titanate nanolayer. During the subsequent in-vitro immersion in a simulated body fluid, the sodium titanate nanolayer induced the nucleation and growth of nanodimensioned calcium phosphate. It was possible to observe the formation of TiO2 nanotubes on the surface of Ti-7.5Mo. Calcium phosphate coating was greater in the samples with larger nanotube diameter. These findings represent a simple surface treatment for Ti-7.5Mo alloy that has high potential for biomedical applications.

scholarly journals Mechanical and Biocompatibility Properties of Calcium Phosphate Bioceramics Derived from Salmon Fish Bone Wastes

2020 ◽  
Vol 21 (21) ◽  
pp. 8082
Author(s):  
Merve Bas ◽  
Sibel Daglilar ◽  
Nilgun Kuskonmaz ◽  
Cevriye Kalkandelen ◽  
Gokce Erdemir ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Sintering Temperature ◽  
Biomedical Application ◽  
Calcium Phosphates ◽  
Biological Properties ◽  
Fish Bone ◽  
Calcination Process ◽  
In Vitro Biocompatibility ◽  
Different Temperatures

Natural calcium phosphates derived from fish wastes are a promising material for biomedical application. However, their sintered ceramics are not fully characterized in terms of mechanical and biological properties. In this study, natural calcium phosphate was synthesized through a thermal calcination process from salmon fish bone wastes. The salmon-derived calcium phosphates (sCaP) were sintered at different temperatures to obtain natural calcium phosphate bioceramics and then were investigated in terms of their microstructure, mechanical properties and biocompatibility. In particular, this work is concerned with the effects of grain size on the relative density and microhardness of the sCaP bioceramics. Ca/P ratio of the sintered sCaP ranged from 1.73 to 1.52 when the sintering temperature was raised from 1000 to 1300 °C. The crystal phase of all the sCaP bioceramics obtained was biphasic and composed of hydroxyapatite (HA) and tricalcium phosphate (TCP). The density and microhardness of the sCaP bioceramics increased in the temperature interval 1000–1100 °C, while at temperatures higher than 1100 °C, these properties were not significantly altered. The highest compressive strength of 116 MPa was recorded for the samples sintered at 1100 °C. In vitro biocompatibility was also examined in the behavior of osteosarcoma (Saos-2) cells, indicating that the sCaP bioceramics had no cytotoxicity effect. Salmon-derived biphasic calcium phosphates (BCP) have the potential to contribute to the development of bone substituted materials.

scholarly journals Mineralization of Titanium Surfaces: Biomimetic Implants

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2879
Author(s):  
Javier Gil ◽  
Jose Maria Manero ◽  
Elisa Ruperez ◽  
Eugenio Velasco-Ortega ◽  
Alvaro Jiménez-Guerra ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Dental Implants ◽  
Early Stage ◽  
Calcium Phosphates ◽  
Biological Fixation ◽  
Biomimetic Surfaces ◽  
Titanium Surfaces ◽  
Deposition Processes ◽  
Fast Dissolution ◽  
Plasma Sprayed

The surface modification by the formation of apatitic compounds, such as hydroxyapatite, improves biological fixation implants at an early stage after implantation. The structure, which is identical to mineral content of human bone, has the potential to be osteoinductive and/or osteoconductive materials. These calcium phosphates provoke the action of the cell signals that interact with the surface after implantation in order to quickly regenerate bone in contact with dental implants with mineral coating. A new generation of calcium phosphate coatings applied on the titanium surfaces of dental implants using laser, plasma-sprayed, laser-ablation, or electrochemical deposition processes produces that response. However, these modifications produce failures and bad responses in long-term behavior. Calcium phosphates films result in heterogeneous degradation due to the lack of crystallinity of the phosphates with a fast dissolution; conversely, the film presents cracks, which produce fractures in the coating. New thermochemical treatments have been developed to obtain biomimetic surfaces with calcium phosphate compounds that overcome the aforementioned problems. Among them, the chemical modification using biomineralization treatments has been extended to other materials, including composites, bioceramics, biopolymers, peptides, organic molecules, and other metallic materials, showing the potential for growing a calcium phosphate layer under biomimetic conditions.

scholarly journals Amorphous–Crystalline Calcium Phosphate Coating Promotes In Vitro Growth of Tumor-Derived Jurkat T Cells Activated by Anti-CD2/CD3/CD28 Antibodies

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3693
Author(s):  
Yurii P. Sharkeev ◽  
Ekaterina G. Komarova ◽  
Valentina V. Chebodaeva ◽  
Mariya B. Sedelnikova ◽  
Aleksandr M. Zakharenko ◽  
...  
Keyword(s):  
T Cells ◽  
Calcium Phosphate ◽  
Biological Effects ◽  
Electrical Potential ◽  
Biological Properties ◽  
Modern Trend ◽  
Calcium Phosphate Coating ◽  
Jurkat T Cells ◽  
Micro Arc Oxidation

A modern trend in traumatology, orthopedics, and implantology is the development of materials and coatings with an amorphous–crystalline structure that exhibits excellent biocopatibility. The structure and physico–chemical and biological properties of calcium phosphate (CaP) coatings deposited on Ti plates using the micro-arc oxidation (MAO) method under different voltages (200, 250, and 300 V) were studied. Amorphous, nanocrystalline, and microcrystalline statesof CaHPO4 and β-Ca2P2O7were observed in the coatings using TEM and XRD. The increase in MAO voltage resulted in augmentation of the surface roughness Ra from 2.5 to 6.5 µm, mass from 10 to 25 mg, thickness from 50 to 105 µm, and Ca/P ratio from 0.3 to 0.6. The electrical potential (EP) of the CaP coatings changed from −456 to −535 mV, while the zeta potential (ZP) decreased from −53 to −40 mV following an increase in the values of the MAO voltage. Numerous correlations of physical and chemical indices of CaP coatings were estimated. A decrease in the ZP magnitudes of CaP coatings deposited at 200–250 V was strongly associated with elevated hTERT expression in tumor-derived Jurkat T cells preliminarily activated with anti-CD2/CD3/CD28 antibodies and then contacted in vitro with CaP-coated samples for 14 days. In turn, in vitro survival of CD4+ subsets was enhanced, with proinflammatory cytokine secretion of activated Jurkat T cells. Thus, the applied MAO voltage allowed the regulation of the physicochemical properties of amorphous–crystalline CaP-coatings on Ti substrates to a certain extent. This method may be used as a technological mechanism to trigger the behavior of cells through contact with micro-arc CaP coatings. The possible role of negative ZP and Ca2+ as effectors of the biological effects of amorphous–crystalline CaP coatings is discussed. Micro-arc CaP coatings should be carefully tested to determine their suitability for use in patients with chronic lymphoid malignancies.

Enhancing the corrosion resistance and surface bioactivity of a calcium-phosphate coating on a biodegradable AZ60 magnesium alloy via a simple fluorine post-treatment method

RSC Advances ◽  
2015 ◽  
Vol 5 (69) ◽  
pp. 56001-56010 ◽  
Author(s):  
Yingchao Su ◽  
Yanbo Lu ◽  
Yichang Su ◽  
Jiangjiang Hu ◽  
Jianshe Lian ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Calcium Phosphate ◽  
Treatment Method ◽  
Post Treatment ◽  
Calcium Phosphate Coating ◽  
Phosphate Coating

A simple fluorine post-treatment was attempted on a calcium-phosphate coating on an AZ60 alloy. Optimum fluorine post-treatment parameters were obtained. The fluorine post-treated coating showed improved corrosion protectiveness and surface bioactivity.

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