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Xuchao P, Yong H, Semirumi DT, Zhong F, Rezaie R. Development of cellulose/hydroxyapatite/TiO 2 scaffolds for efficient removal of lead (II) ions pollution: Characterization, kinetic analysis, and artificial neural network modeling. Int J Biol Macromol 2023; 246:125630. [PMID: 37394219 DOI: 10.1016/j.ijbiomac.2023.125630] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 06/26/2023] [Accepted: 06/28/2023] [Indexed: 07/04/2023]
Abstract
The utilization of nano-biodegradable composites for removing pollutants and heavy metals in aquatic environments has been widespread. This study focuses on synthesizing cellulose/hydroxyapatite nanocomposites with titanium dioxide (TiO2) via the freeze-drying method for the adsorption of lead ions in aquatic environments. The physical and chemical properties of the nanocomposites, including structure, morphology, and mechanical properties, were analyzed through FTIR, XRD, SEM, and EDS. In addition, parameters affecting the adsorption capacity, such as time, temperature, pH, and initial concentration, were determined. The nanocomposite exhibited a maximum adsorption capacity of 1012 mg⸱g-1, and the second-order kinetic model was found to govern the adsorption process. Additionally, an artificial neural network (ANN) was created using weight percentages (wt%) of nanoparticles included in the scaffold to predict the mechanical behavior, porosity, and desorption of the scaffolds at various weight percentages of hydroxyapatite (nHAP) and TiO2. The results of the ANN indicated that the incorporation of both single and hybrid nanoparticles into the scaffolds improved their mechanical behavior and desorption, as well as increased their porosity.
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Affiliation(s)
- Pan Xuchao
- School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - He Yong
- School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - D T Semirumi
- Ceramic Engineering Research Center, Scientific and Research Town, Isfahan, Iran
| | - Fang Zhong
- School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - R Rezaie
- Ceramic Engineering Research Center, Scientific and Research Town, Isfahan, Iran
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Boonrawd W, Awad K, Varanasi V, Meletis EI. Surface Characteristics and In-Vitro Studies of TiO 2 Coatings by Plasma Electrolytic Oxidation in Potassium-Phosphate Electrolyte. CERAMICS INTERNATIONAL 2022; 48:7071-7081. [PMID: 35177876 PMCID: PMC8846569 DOI: 10.1016/j.ceramint.2021.11.266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Plasma electrolytic oxidation (PEO) was used to produce titanium oxide (TiO2) coatings on Ti surface in potassium - phosphate electrolyte. The morphology, wettability, phase, and chemical compositions were studied as a function of processing parameters. The bioactivity of the coating was assessed by the ability to form biomimetic apatite in-vitro using cell culture medium. In-vitro studies using human mesenchymal stem cells were also conducted to evaluate cells' proliferation and viability of the treated Ti. The results revealed that the produced TiO2 coatings comprised pore features with the pore size increasing with applied current density and treatment duration due to high energy discharge channels at higher potential. The PEO treated Ti exhibited superhydrophilic characteristics with a contact angle <1°. The findings indicated that the large actual surface area produced by the PEO treatment and the presence of negatively charge P O 4 3 - are the key factors for the superhydrophilic behavior. The in-vitro studies revealed that the PEO treated groups had higher amount of biomimetic apatite formation compared to the as-polished Ti. The PEO treatment significantly enhanced the cells' adhesion and growth after 24 and 72 hrs compared to the untreated Ti. A significant difference in the bioactivity was not observed between anatase and rutile.
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Affiliation(s)
- Wisanu Boonrawd
- Department of Materials Science and Engineering, The University of Texas at Arlington, Arlington, TX 76013, USA
- Department of Industrial Engineering, Burapha University, 169 Longhard Bangsaen rd, Saensook, Muang Chonburi 20131, Thailand
| | - Kamal Awad
- Department of Materials Science and Engineering, The University of Texas at Arlington, Arlington, TX 76013, USA
- Bone Muscle Research Center, The University of Texas at Arlington, Arlington, TX 76013, USA
| | - Venu Varanasi
- Department of Materials Science and Engineering, The University of Texas at Arlington, Arlington, TX 76013, USA
- Bone Muscle Research Center, The University of Texas at Arlington, Arlington, TX 76013, USA
| | - Efstathios I Meletis
- Department of Materials Science and Engineering, The University of Texas at Arlington, Arlington, TX 76013, USA
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Jaafar A, Hecker C, Árki P, Joseph Y. Sol-Gel Derived Hydroxyapatite Coatings for Titanium Implants: A Review. Bioengineering (Basel) 2020; 7:bioengineering7040127. [PMID: 33066421 PMCID: PMC7711523 DOI: 10.3390/bioengineering7040127] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/05/2020] [Accepted: 10/10/2020] [Indexed: 01/02/2023] Open
Abstract
With the growing demands for bone implant therapy, titanium (Ti) and its alloys are considered as appropriate choices for the load-bearing bone implant substitutes. However, the interaction of bare Ti-based implants with the tissues is critical to the success of the implants for long-term stability. Thus, surface modifications of Ti implants with biocompatible hydroxyapatite (HAp) coatings before implantation is important and gained interest. Sol-gel is a potential technique for deposition the biocompatible HAp and has many advantages over other methods. Therefore, this review strives to provide widespread overview on the recent development of sol-gel HAp deposition on Ti. This study shows that sol-gel technique was able to produce uniform and homogenous HAp coatings and identified the role of surface pretreatment of Ti substrate, optimizing the sol-gel parameters, substitution, and reinforcement of HAp on improving the coating properties. Critical factors that influence on the characteristics of the deposited sol-gel HAp films as corrosion resistance, adhesion to substrate, bioactivity, morphological, and structural properties are discussed. The review also highlights the critical issues, the most significant challenges, and the areas requiring further research.
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Low-Cost Deposition of Antibacterial Ion-Substituted Hydroxyapatite Coatings onto 316L Stainless Steel for Biomedical and Dental Applications. COATINGS 2020. [DOI: 10.3390/coatings10090880] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Substitutions of ions into an apatitic lattice may result in antibacterial properties. In this study, magnesium (Mg)-, zinc (Zn)-, and silicon (Si)-substituted hydroxyapatite (HA) were synthesized using a microwave irradiation technique. Polyvinyl alcohol (PVA) was added during the synthesis of the substituted HA as a binding agent. The synthesized Mg-, Zn-, and Si-substituted HAs were then coated onto a 316L-grade stainless-steel substrate using low-cost electrophoretic deposition (EPD), thereby avoiding exposure to high temperatures. The deposited layer thickness was measured and the structural, phase and morphological analysis were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The bacterial adhesion of Staphylococcus aureus was characterized at 30 min, 2 h and 6 h. The results showed homogeneous, uniform thickness (50–70 µm) of the substrate. FTIR and XRD showed the characteristic spectral peaks of HA, where the presence of Mg, Zn and Si changed the spectral peak intensities. The Mg–HA coating showed the least bacterial adhesion at 30 min and 2 h. In contrast, the Si–HA coating showed the least adhesion at 6 h. EPD showed an effective way to get a uniform coating on bio-grade metal implants, where ionic-substituted HA appeared as alternative coating material compared to conventional HA and showed the least bacterial adhesion.
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Lu M, Chen H, Yuan B, Zhou Y, Min L, Xiao Z, Zhu X, Tu C, Zhang X. Electrochemical Deposition of Nanostructured Hydroxyapatite Coating on Titanium with Enhanced Early Stage Osteogenic Activity and Osseointegration. Int J Nanomedicine 2020; 15:6605-6618. [PMID: 32982221 PMCID: PMC7490093 DOI: 10.2147/ijn.s268372] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/26/2020] [Indexed: 02/05/2023] Open
Abstract
Purpose The aim of research is to fabricate nanostructured hydroxyapatite (HA) coatings on the titanium via electrochemical deposition (ED). Additionally, the biological properties of the ED-produced HA (EDHA) coatings with a plate-like nanostructure were evaluated in vitro and in vivo by undertaking comparisons with those prepared by acid/alkali (AA) treatment and by plasma spray-produced HA (PSHA) nanotopography-free coatings. Materials and Methods Nanoplate-like HA coatings were prepared through ED, and nanotopography-free PSHA coatings were fabricated. The surface morphology, phase composition, roughness, and wettability of these samples were investigated. Furthermore, the growth, proliferation, and osteogenic differentiation of MC3T3-E1 cells cultured on each sample were evaluated via in vitro experiments. Histological assessment and push-out tests for the bone–implant interface were performed to explore the effect of the EDHA coatings on the interfacial osseointegration in vivo. Results XRD analysis showed that the strongest intensity for the EDHA coatings was at the (002) plane rather than at the regular (211) plane. Relatively higher surface roughness and greater wettability were observed for the EDHA coatings. Cellular experiments revealed that the plate-like nanostructured EDHA coatings not only possessed an ability, similar to that of PSHA coatings, to promote the adhesion and proliferation of MC3T3-E1 cells but also demonstrated significantly enhanced early or intermediate markers of osteogenic differentiation. Significant osseointegration enhancement in the early stage of implantation period and great bonding strength were observed at the interface of bone and EDHA samples. In comparison, relatively weak osseointegration and bonding strength of the bone–implant interface were observed for the AA treatment. Conclusion The biological performance of the plate-like nanostructured EDHA coating, which was comparable with that of the PSHA, improves early-stage osteogenic differentiation and osseointegration abilities and has great potential for enhancing the initial stability and long-term survival of uncemented or 3D porous titanium implants.
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Affiliation(s)
- Minxun Lu
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, People's Republic of China.,National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, People's Republic of China
| | - Hongjie Chen
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, People's Republic of China
| | - Bo Yuan
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, People's Republic of China
| | - Yong Zhou
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Li Min
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Zhanwen Xiao
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, People's Republic of China
| | - Xiangdong Zhu
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, People's Republic of China
| | - Chongqi Tu
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Xingdong Zhang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, People's Republic of China
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Ho YH, Man K, Joshi SS, Pantawane MV, Wu TC, Yang Y, Dahotre NB. In-vitro biomineralization and biocompatibility of friction stir additively manufactured AZ31B magnesium alloy-hydroxyapatite composites. Bioact Mater 2020; 5:891-901. [PMID: 32637752 PMCID: PMC7332469 DOI: 10.1016/j.bioactmat.2020.06.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/08/2020] [Accepted: 06/12/2020] [Indexed: 01/08/2023] Open
Abstract
The present study aims to evaluate effect of hydroxyapatite (HA, Ca10(PO4)6OH2), a ceramic similar to natural bone, into AZ31B Mg alloy matrix on biomineralization and biocompatibility. The novel friction stir processing additive manufacturing route was employed to fabricate Mg-HA composites. Various HA contents (5, 10, 20 wt%) were incorporated into Mg matrix. Microstructural observation and chemical composition analysis revealed that refined Mg grains and dispersion of HA particles at micro/nanoscales were achieved in Mg-HA composites after the friction stir processing. The biomineralization evaluation were carried out using immersion experiments in simulated body fluid followed by mineral morphology observation and chemical composition analysis. The wettability measurements were conducted to correlate the biomineralization behavior. The results showed improvement in wettability and bone-like Ca/P ratio in apatite deposit on the composites compared to as-received Mg. In addition, the increase of blood compatibility, cell viability and spreading were found in the higher HA content composites, indicating the improved biocompatibility. Therefore, friction stir processed Mg-20 wt%HA composite exhibited the highest wettability and better cell adhesion among other composites due to the effect of increased HA content within Mg matrix. Friction stir additive manufacturing technique was employed to fabricate AZ31B magnesium-hydroxyapatite composite. Hydroxyapatite incorporated in Mg matrix varied from micro-to nano-length scales. Refined microstructure and increase in hydroxyapatite content enhanced wettability, biomineralization, and biocompatibility.
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Affiliation(s)
- Yee-Hsien Ho
- Laboratory for Laser Aided Additive and Subtractive Manufacturing, Department of Materials Science and Engineering, University of North Texas, 1150 Union Circle 305310, Denton, TX, 76203-5017, USA
| | - Kun Man
- Department of Biomedical Engineering, University of North Texas, 1150 Union Circle 305310, Denton, TX, 76203-5017, USA
| | - Sameehan S Joshi
- Laboratory for Laser Aided Additive and Subtractive Manufacturing, Department of Materials Science and Engineering, University of North Texas, 1150 Union Circle 305310, Denton, TX, 76203-5017, USA
| | - Mangesh V Pantawane
- Laboratory for Laser Aided Additive and Subtractive Manufacturing, Department of Materials Science and Engineering, University of North Texas, 1150 Union Circle 305310, Denton, TX, 76203-5017, USA
| | - Tso-Chang Wu
- Laboratory for Laser Aided Additive and Subtractive Manufacturing, Department of Materials Science and Engineering, University of North Texas, 1150 Union Circle 305310, Denton, TX, 76203-5017, USA
| | - Yong Yang
- Department of Biomedical Engineering, University of North Texas, 1150 Union Circle 305310, Denton, TX, 76203-5017, USA
| | - Narendra B Dahotre
- Laboratory for Laser Aided Additive and Subtractive Manufacturing, Department of Materials Science and Engineering, University of North Texas, 1150 Union Circle 305310, Denton, TX, 76203-5017, USA
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Kołbuk D, Urbanek O, Denis P, Choińska E. Sonochemical coating as an effective method of polymeric nonwovens functionalization. J Biomed Mater Res A 2019; 107:2447-2457. [DOI: 10.1002/jbm.a.36751] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 06/17/2019] [Accepted: 06/20/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Dorota Kołbuk
- Institute of Fundamental Technological Research, Polish Academy of Sciences Warsaw Poland
| | - Olga Urbanek
- Institute of Fundamental Technological Research, Polish Academy of Sciences Warsaw Poland
| | - Piotr Denis
- Institute of Fundamental Technological Research, Polish Academy of Sciences Warsaw Poland
| | - Emilia Choińska
- Faculty of Materials Science and EngineeringWarsaw University of Technology Warsaw Poland
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Taborda JAP, López EO. Research Perspectives on Functional Micro and Nano Scale Coatings. RESEARCH PERSPECTIVES ON FUNCTIONAL MICRO- AND NANOSCALE COATINGS 2016. [DOI: 10.4018/978-1-5225-0066-7.ch006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Research topics related to the production of nanocomposites are the most important directions of development of new semiconductor engineering, ensuring high nanocomposites obtaining useful properties in the scope of biophysical characteristics, biomedical and piezoelectric applications. We present two case studies as Hydroxyapatite are in medical applications and aluminum nitride as acoustic wave sensor. Hydroxyapatite, is the main inorganic structure of the tooth enamel and bone and is a biomaterial that is commonly used in biomedical applications that involve bone substitution, drug delivery and bone regeneration because of its excellent biocompatibility, high bioactivity and good osseoconductivity. Since the past decade. Aluminum nitride (AlN), an electrical insulating ceramic with a wide band gap of 6.3 eV, is a potentially useful dielectric material very important in fields such as optoelectronic and micro electronics.
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Demnati I, Grossin D, Marsan O, Bertrand G, Collonges G, Combes C, Parco M, Braceras I, Alexis J, Balcaen Y, Rey C. Comparison of Physical-chemical and Mechanical Properties of Chlorapatite and Hydroxyapatite Plasma Sprayed Coatings. Open Biomed Eng J 2015; 9:42-55. [PMID: 25893015 PMCID: PMC4391221 DOI: 10.2174/1874120701509010042] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Revised: 08/02/2014] [Accepted: 08/20/2014] [Indexed: 11/22/2022] Open
Abstract
Chlorapatite can be considered a potential biomaterial for orthopaedic applications. Its use as plasma-sprayed coating could be of interest considering its thermal properties and particularly its ability to melt without decomposition unlike hydroxyapatite. Chlorapatite (ClA) was synthesized by a high-temperature ion exchange reaction starting from commercial stoichiometric hydroxyapatites (HA). The ClA powder showed similar characteristics as the original industrial HA powder, and was obtained in the monoclinic form. The HA and ClA powders were plasma-sprayed using a low-energy plasma spraying system with identical processing parameters. The coatings were characterized by physical-chemical methods, i.e. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy, including distribution mapping of the main phases detected such as amorphous calcium phosphate (ACP), oxyapatite (OA), and HA or ClA. The unexpected formation of oxyapatite in ClA coatings was assigned to a side reaction with contaminating oxygenated species (O2, H2O). ClA coatings exhibited characteristics different from HA, showing a lower content of oxyapatite and amorphous phase. Although their adhesion strength was found to be lower than that of HA coatings, their application could be an interesting alternative, offering, in particular, a larger range of spraying conditions without formation of massive impurities.
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Affiliation(s)
- Imane Demnati
- Université de Toulouse, CIRIMAT, INPT-CNRS-UPS, ENSIACET, Toulouse, France
| | - David Grossin
- Université de Toulouse, CIRIMAT, INPT-CNRS-UPS, ENSIACET, Toulouse, France
| | - Olivier Marsan
- Université de Toulouse, CIRIMAT, INPT-CNRS-UPS, ENSIACET, Toulouse, France
| | - Ghislaine Bertrand
- Université de Toulouse, CIRIMAT, INPT-CNRS-UPS, ENSIACET, Toulouse, France
| | | | - Christèle Combes
- Université de Toulouse, CIRIMAT, INPT-CNRS-UPS, ENSIACET, Toulouse, France
| | - Maria Parco
- Tecnalia, Mikeletegi Pasealekua 2, Donostia-San Sebastian, Spain
| | - Inigo Braceras
- Tecnalia, Mikeletegi Pasealekua 2, Donostia-San Sebastian, Spain
| | - Joel Alexis
- Université de Toulouse, INPT-ENIT, Laboratoire Génie de Production, Tarbes, France
| | - Yannick Balcaen
- Université de Toulouse, INPT-ENIT, Laboratoire Génie de Production, Tarbes, France
| | - Christian Rey
- Université de Toulouse, CIRIMAT, INPT-CNRS-UPS, ENSIACET, Toulouse, France
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Loszach M, Gitzhofer F. Induction suspension plasma sprayed biological-like hydroxyapatite coatings. J Biomater Appl 2015; 29:1256-71. [DOI: 10.1177/0885328214562435] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Substituted hydroxyapatite coatings with different ions (Mg, Na, K, Cl, F) have been developed by the induction suspension plasma spray process. Suspensions were prepared with sol–gel. The main objective of this study was to demonstrate that induction suspension plasma spray technology possesses high material composition flexibility that allows as-sprayed coatings to closely mimic natural bone composition. Long-term in vitro behaviour of as-sprayed substituted coatings was evaluated with simulated body fluid. Data on the suspensions showed the formation of a pure hydroxyapatite phase. Transmission electron microscopy characterized various preparation stages of the suspensions. As-sprayed samples were distinguished by X-ray diffraction and scanning electron microscopy. Substituted elements were quantified by neutron activation. A well-crystallized hydroxyapatite phase was produced with concentration in various substitutions very close to natural bone composition. Ca/P and (Ca + Mg + Na + K)/P ratios provided evidence of the introduction of different cations into apatite structures. The immersion of samples into simulated body fluid led to the nucleation and growth of a flake-like octacalcium phosphate crystal layer at the surface of as-sprayed coatings after one week. Proof of octacalcium phosphate transformation and its partial dissolution and direct re-precipitation into apatite was disclosed by local energy dispersive spectroscopy and microstructure observation. Formation of a Ca/P ratio gradient from the precipitated layer surface to the as-sprayed coatings interface was observed after four weeks once the octacalcium phosphate crystals reached a critical size, resulting in the formation of a rich apatite layer at the interface after six weeks. A set of mechanisms has been proposed to explain these findings.
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Affiliation(s)
- Max Loszach
- Department of Chemical and Biotechnological Engineering, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - François Gitzhofer
- Department of Chemical and Biotechnological Engineering, Université de Sherbrooke, Sherbrooke, Québec, Canada
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Sörensen JH, Lilja M, Sörensen TC, Åstrand M, Procter P, Fuchs S, Strømme M, Steckel H. Biomechanical and antibacterial properties of Tobramycin loaded hydroxyapatite coated fixation pins. J Biomed Mater Res B Appl Biomater 2014; 102:1381-92. [PMID: 24677812 DOI: 10.1002/jbm.b.33117] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 01/06/2014] [Accepted: 01/11/2014] [Indexed: 11/09/2022]
Abstract
The present study investigates the use of nanoporous, biomimetic hydroxyapatite (HA) coatings deposited on TiO₂ coated fixation pins as functional implant surfaces for the local release of Tobramycin in order to prevent bacterial colonization. The impact of HA-coating thickness, coating morphology and biomechanical forces during insertion into synthetic bone on the drug loading and release properties are analyzed. The coatings are shown to exhibit bactericidal effects against Staphylococcus aureus in agar medium for a duration of 6 days after loading by adsorption with Tobramycin for only 5 min at elevated temperature and pressure. Furthermore, high performance liquid chromatography analysis shows a drug release in phosphate buffered saline for 8 days with antibiotic concentration remaining above the minimal inhibitory concentration for S. aureus during the entire release period. Biomechanical insertion tests into synthetic bone and conventional scratch testing demonstrate adhesive strength at the HA/TiO₂ interface. Biocompatibility is verified by cell viability tests. Outgrowth endothelial cells, as well as primary osteoblasts, are viable and firmly attached to both HA and TiO₂ surfaces. The results presented are encouraging and support the concept of functional HA coatings as local drug delivery vehicles for biomedical applications to treat as well as to prevent post-surgical infections.
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Affiliation(s)
- Jan Henrik Sörensen
- Department of Pharmaceutics and Biopharmaceutics, Christian Albrecht University Kiel, 24118, Kiel, Germany
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Zhao SF, Dong WJ, Jiang QH, He FM, Wang XX, Yang GL. Effects of zinc-substituted nano-hydroxyapatite coatings on bone integration with implant surfaces. J Zhejiang Univ Sci B 2014; 14:518-25. [PMID: 23733429 DOI: 10.1631/jzus.b1200327] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The purpose of this study was to investigate the effects of a zinc-substituted nano-hydroxyapatite (Zn-HA) coating, applied by an electrochemical process, on implant osseointegraton in a rabbit model. METHODS A Zn-HA coating or an HA coating was deposited using an electrochemical process. Surface morphology was examined using field-emission scanning electron microscopy. The crystal structure and chemical composition of the coatings were examined using an X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR). A total of 78 implants were inserted into femurs and tibias of rabbits. After two, four, and eight weeks, femurs and tibias were retrieved and prepared for histomorphometric evaluation and removal torque (RTQ) tests. RESULTS Rod-like HA crystals appeared on both implant surfaces. The dimensions of the Zn-HA crystals seemed to be smaller than those of HA. XRD patterns showed that the peaks of both coatings matched well with standard HA patterns. FTIR spectra showed that both coatings consisted of HA crystals. The Zn-HA coating significantly improved the bone area within all threads after four and eight weeks (P<0.05), the bone to implant contact (BIC) at four weeks (P<0.05), and RTQ values after four and eight weeks (P<0.05). CONCLUSIONS The study showed that an electrochemically deposited Zn-HA coating has potential for improving bone integration with an implant surface.
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Affiliation(s)
- Shi-fang Zhao
- Department of Oral Implantology, Affiliated Stomatology Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, China
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Saber-Samandari S, Alamara K, Saber-Samandari S, Gross KA. Micro-Raman spectroscopy shows how the coating process affects the characteristics of hydroxylapatite. Acta Biomater 2013; 9:9538-46. [PMID: 23973389 DOI: 10.1016/j.actbio.2013.08.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 07/29/2013] [Accepted: 08/12/2013] [Indexed: 10/26/2022]
Abstract
The diversity in the structural and chemical state of apatites allows implant manufacturers to fine-tune implant properties. This requires suitable manufacturing processes and characterization tools to adjust the amorphous phase and hydroxyl content from the source hydroxylapatite. Hydroxylapatite was processed by high-velocity oxy-fuel spraying, plasma spraying and flame spraying, and primarily analyzed by Raman spectroscopy. Investigation of rounded splats, the building blocks of thermal spray coatings, allowed correlation between the visual identity of the splat surface and the Raman spectra. Splats were heat-treated to crystallize any remaining amorphous phase. The ν1 PO4 stretching peak at 950-970 cm(-1) displayed the crystalline order, but the hydroxyl peak at 3572 cm(-1) followed the degree of dehydroxylation. Hydroxyl loss was greatest for flame-sprayed particles, which create the longest residence time for the melted particle. Higher-frequency hydroxyl peaks in flame- and plasma-sprayed splats indicated a lower structural order for the recrystallized hydroxylapatite within the splats. Crystallization at 700 °C has shown potential for revealing hydroxyl ions previously trapped in amorphous calcium phosphate. This work compares Fourier transform infrared and Raman spectroscopy to measure the hydroxyl content in rapidly solidified apatites and shows that Raman spectroscopy is more suitable.
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López EO, Mello A, Sendão H, Costa LT, Rossi AL, Ospina RO, Borghi FF, Silva Filho JG, Rossi AM. Growth of crystalline hydroxyapatite thin films at room temperature by tuning the energy of the RF-magnetron sputtering plasma. ACS APPLIED MATERIALS & INTERFACES 2013; 5:9435-9445. [PMID: 24059686 DOI: 10.1021/am4020007] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Right angle radio frequency magnetron sputtering technique (RAMS) was redesigned to favor the production of high-quality hydroxyapatite (HA) thin coatings for biomedical applications. Stoichiometric HA films with controlled crystallinity, thickness varying from 254 to 540 nm, crystallite mean size of 73 nm, and RMS roughness of 1.7 ± 0.9 nm, were obtained at room temperature by tuning the thermodynamic properties of the plasma sheath energy. The plasma energies were adjusted by using a suitable high magnetic field confinement of 143 mT (1430 G) and a substrate floating potential of 2 V at the substrate-to-magnetron distance of Z = 10 mm and by varying the sputtering geometry, substrate-to-magnetron distance from Z = 5 mm to Z = 18 mm, forwarded RF power and reactive gas pressure. Measurements that were taken with a Langmuir probe showed that the adjusted RAMS geometry generated a plasma with an adequate effective temperature of Teff ≈ 11.8 eV and electron density of 2.0 × 10(15) m(-3) to nucleate nanoclusters and to further crystallize the nanodomains of stoichiometric HA. The deposition mechanism in the RAMS geometry was described by the formation of building units of amorphous calcium phosphate clusters (ACP), the conversion into HA nanodomains and the crystallization of the grain domains with a preferential orientation along the HA [002] direction.
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Affiliation(s)
- Elvis O López
- Department of Applied Physics, Brazilian Center for Physics Research , Urca, Rio de Janeiro 22290-180, Brazil
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SAITO A, SAITO E, KUBOKI Y, KIMURA M, NAKAJIMA T, YUGE F, KATO T, HONMA Y, TAKAHASHI T, OHATA N. Periodontal regeneration following application of basic fibroblast growth factor-2 in combination with beta tricalcium phosphate in class III furcation defects in dogs. Dent Mater J 2013; 32:256-62. [DOI: 10.4012/dmj.2012-171] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Qiu D, Zhang M, Grøndahl L. A novel composite porous coating approach for bioactive titanium-based orthopedic implants. J Biomed Mater Res A 2012; 101:862-72. [PMID: 22968836 DOI: 10.1002/jbm.a.34372] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 06/26/2012] [Indexed: 11/11/2022]
Abstract
Surface modification of titanium-based implants is considered a highly effective solution to enhance osseointegration. This study describes a novel Ti/hydroxyapatite (HA) composite porous coating produced using a cold spraying technique. Experimental results indicate desirable open-cell structure with 50-150 μm pore size and 60-65% macroporosity. In particular, the reinforced HA particles are exposed to the surface of the coating resulting in enhanced mineralization ability in simulated body fluid. None of the coatings displayed a cytotoxic response in SaOS-2 cells cultured in vitro for up to 48 h. The bond strength between the porous coating and the Ti substrate was found to be 20 MPa. These properties are comparative to or better than products currently on the market and thus this novel coating has potential use in orthopedics.
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Affiliation(s)
- Dong Qiu
- School of Mechanical and Mining Engineering, University of Queensland, St. Lucia, Queensland, Australia
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17
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Bioactive ceramic coating of cancellous screws improves the osseointegration in the cancellous bone. J Orthop Sci 2011; 16:291-7. [PMID: 21442188 DOI: 10.1007/s00776-011-0047-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2010] [Accepted: 01/14/2011] [Indexed: 02/09/2023]
Abstract
BACKGROUND A number of methods for coating implants with bioactive ceramics have been reported to improve osseointegration in bone, but the effects of bioactive ceramic coatings on the osseointegration of cancellous screws are not known. Accordingly, biomechanical and histomorphometric analyses of the bone-screw interface of uncoated cancellous screws and cancellous screws coated with four different bioactive ceramics were performed. METHODS After coating titanium alloy cancellous screws with calcium pyrophosphate (CPP), CaO-SiO(2)-B(2)O(3) glass-ceramics (CSG), apatite-wollastonite 1:3 glass-ceramics (W3G), and CaO-SiO(2)-P(2)O(5)-B(2)O(3) glass-ceramics (BGS-7) using an enameling method, the coated and the uncoated screws were inserted into the proximal tibia and distal femur metaphysis of seven male mongrel dogs. The torque values of the screws were measured at the time of insertion and at removal after 8 weeks. The bone-screw contact ratio was analyzed by histomorphometry. RESULTS There was no significant difference in the insertion torque between the uncoated and coated screws. The torque values of the CPP and BGS-7 groups measured at removal after 8 weeks were significantly higher than those of the uncoated group. Moreover, the values of the CPP and BGS-7 groups were significantly higher than the insertion torques. The fraction of bone-screw interface measured from the undecalcified histological slide showed that the CPP, W3G, and BGS-7 groups had significantly higher torque values in the cortical bone area than the uncoated group, and the CPP and BGS-7 groups had significantly higher torque values in the cancellous bone area than the uncoated group. CONCLUSIONS In conclusion, a cancellous screw coated with CPP and BGS-7 ceramic bonds directly to cancellous bone to improve the bone-implant osseointegration. This may broaden the indications for cancellous screws by clarifying their contribution to improving osseointegration, even in the cancellous bone area.
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Zhou P, Asanami S, Kawana H, Hosonuma M, Mitsui H, Zhou H. Double Layered HA Coating, its Characterization and Preparation. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-550-255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractHydroxyapatite (HA) has been universally used because of good biocompatibility. There are varieties of coating methods, however, they still have problems. The most significant problem is layer thickness. We introduced a new coating procedure to eliminate this difficulty.The characterization of the coating was studied by X-ray diffractometry, infrared spectroscopy, SEM and chemical analysis. Said examination indicated that the double layer consisted of carbonate HA and CaTiO3 and the thickness of the layer was 2-4 μm. The coating was performed on the inner surfaces of 50-200 μm sized pores and was also consistent in the smallest of the pores even those of 50 μm. Our results indicated that the coating layer was homogeneous and thin. In addition, both layers consisted of Ca ions. The consistency of coating into even the smallest pore size suggested that our method promises to have widespread clinical applications in artificial implants because of increased surface contact area.
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Nancollas GH, Wu W, Tang R. The Control of Mineralization on Natural and Implant Surfaces. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-599-99] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractThe generation of minerals such as calcium phosphates on the surfaces of dental and joint replacement implants is beneficial since the facilitation of bone formation permits their fixation. In contrast, the prevention of crystallization is desired on other surfaces such as kidney and cardiac valve prostheses. A key to the development of successful biomaterials is therefore an understanding of the factors that control crystal nucleation, growth and dissolution in aqueous solution. The Constant Composition method was used to investigate the influence of factors such as solution composition, ionic strength, pH and temperature on the crystallization and dissolution of the calcium phosphates, brushite (DCPD), octacalcium phosphate (OCP), hydroxyapatite (HAP) and fluorapatite (FAP). In parallel with these studies, a contact angle method along with surface tension component theory was employed to investigate the roles of interfacial free energy in mineralization and demineralization. Values of the interfacial tensions, -4.2, 4.3, 10.4 and 18.5 mJm-2 obtained from contact angle measurements for DCPD, OCP, HAP and FAP, respectively, compare well with those calculated from dissolution kinetics experiments and provide information concerning the growth and dissolution mechanisms. The exploitation of these approaches is illustrated in studies of the coating of specific calcium phosphate phases on titanium metal and alloy surfaces and nucleation and growth of OCP on polymer surfaces modified by silanization to produce amine- and carboxylterminated end groups. In all these reactions involving the calcium phosphates, concomitant dissolution reactions are often involved. Constant Composition kinetic studies have shown that the rate of these reactions decrease markedly with time despite a sustained driving force, and eventually, the rates approach zero even though crystals remain in the undersaturated solutions. Dissolution can be reinitiated by exposing the crystals to the solutions of different undersaturations. These results suggest that dislocation sizes play a significant role in the dissolution kinetic processes.
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Moseke C, Gbureck U. Tetracalcium phosphate: Synthesis, properties and biomedical applications. Acta Biomater 2010; 6:3815-23. [PMID: 20438869 DOI: 10.1016/j.actbio.2010.04.020] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 04/21/2010] [Accepted: 04/23/2010] [Indexed: 10/19/2022]
Abstract
Monoclinic tetracalcium phosphate (TTCP, Ca(4)(PO(4))(2)O), also known by the mineral name hilgenstockite, is formed in the (CaO-P(2)O(5)) system at temperatures>1300 degrees C. TTCP is the only calcium phosphate with a Ca/P ratio greater than hydroxyapatite (HA). It appears as a by-product in plasma-sprayed HA coatings and shows moderate reactivity and concurrent solubility when combined with acidic calcium phosphates such as dicalcium phosphate anhydrous (DCPA, monetite) or dicalcium phosphate dihydrate (DCPD, brushite). Therefore it is widely used in self-setting calcium phosphate bone cements, which form HA under physiological conditions. This paper aims to review the synthesis and properties of TTCP in biomaterials applications such as cements, sintered ceramics and coatings on implant metals.
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Nandakumar A, Yang L, Habibovic P, van Blitterswijk C. Calcium phosphate coated electrospun fiber matrices as scaffolds for bone tissue engineering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:7380-7. [PMID: 20039599 DOI: 10.1021/la904406b] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Electrospun polymeric scaffolds are used for various tissue engineering applications. In this study, we applied a biomimetic coating method to provide electrospun scaffolds from a block copolymer-poly(ethylene oxide terephthalate)-poly(buthylene terephthalate), with a calcium phosphate layer to improve their bioactivity in bone tissue engineering. The in vitro studies with human mesenchymal stem cells demonstrated cell proliferation on both uncoated and coated samples. No significant effect of calcium phosphate coating was observed on the expression of alkaline phosphatase in vitro. Implantation of scaffold-goat mesenchymal stem cells constructs subcutaneously in nude mice resulted in bone formation in the calcium phosphate coated samples, in contrast to the uncoated ones, where no new bone formation was observed. The results of this study showed that the biomimetic method can successfully be used to coat electrospun scaffolds with a calcium phosphate layer, which improved the in vivo bioactivity of the polymer.
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Affiliation(s)
- Anandkumar Nandakumar
- Department of Tissue Regeneration, MIRA-Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, PO Box 217, 7500 AE, The Netherlands
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Inoue M, Rodriguez AP, Takagi T, Katase N, Kubota M, Nagai N, Nagatsuka H, Inoue M, Nagaoka N, Takagi S, Suzuki K. Effect of a New Titanium Coating Material (CaTiO3-aC) Prepared by Thermal Decomposition Method on Osteoblastic Cell Response. J Biomater Appl 2009; 24:657-72. [DOI: 10.1177/0885328209340334] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Titanium and hydroxyapatite (HA) are widely used as biomaterials for dental and medical applications. HA-coated titanium implants have excellent biocompatibility and mechanical properties. However, the adherence of HA film formed on titanium substrate is weak because of the lack of chemical interaction between HA and titanium. A solution to this problem is to form an intermediate film on titanium substrate, which provide excellent adherence to both titanium substrate and HA. We developed a novel biomaterial called calcium titanate-amorphous carbon (CaTiO3-aC) coating prepared by modified thermal decomposition method. The purpose of this study was to evaluate the effect of CaTiO 3-aC and HA coating (positive control), and Ti (negative control) on osteoblastic (MT3T3-E1) cell responses. An increased cellular proliferation was observed in CaTiO3-aC coating compared to HA coating. The maximum expressions of ALP activity, Col I and ALP mRNA were higher and achieved in shorter period of time in CaTiO3-aC coating compared to others. These results demonstrated that CaTiO3-aC promoted better cell attachment, cellular proliferation, and osteoblastic differentiation compared with HA. In conclusion, we suggested that CaTiO3-aC could be considered as an important candidate as a coating material.
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Affiliation(s)
- Miho Inoue
- Department of Oral Pathology and Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-Cho, Okayama 700-8525, Japan,
| | - Andrea P. Rodriguez
- Department of Oral Pathology and Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-Cho, Okayama 700-8525, Japan
| | - Tohru Takagi
- Department of Oral Pathology and Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-Cho, Okayama 700-8525, Japan
| | - Naoki Katase
- Department of Oral Pathology and Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-Cho, Okayama 700-8525, Japan
| | - Midori Kubota
- Department of Oral Pathology and Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-Cho, Okayama 700-8525, Japan
| | - Noriyuki Nagai
- Department of Oral Pathology and Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-Cho, Okayama 700-8525, Japan, Center of Oral Health Science, International Dental Hygienist College in Okayama, Motoyama Gakuin, 3-2-18 Daiku, Okayama 700-0913, Japan
| | - Hitoshi Nagatsuka
- Department of Oral Pathology and Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-Cho, Okayama 700-8525, Japan
| | - Masahisa Inoue
- Laboratory for Structure and Function, Faculty of Pharmaceutical Sciences, Tokushima Bunri University 180 Yamashiro-Cho Nishihamabouji, Tokushima 770-8514, Japan
| | - Noriyuki Nagaoka
- Laboratory for Electron Microscopy, Graduate School of Medicine Dentistry and Pharmaceutical Sciences, Okayama University 2-5-1 Shikata-Cho, Okayama 700-8525, Japan
| | - Shin Takagi
- Department of Oral and Maxillofacial Reconstructive Surgery Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Okayama University, 2-5-1 Shikata-Cho, Okayama 700-8525, Japan
| | - Kazuomi Suzuki
- Department of Biomaterials, Graduate School of Medicine Dentistry and Pharmaceutical Sciences, Okayama University 2-5-1 Shikata-Cho, Okayama 700-8525, Japan
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Yamaguchi S, Yabutsuka T, Hibino M, Yao T. Development of novel bioactive composites by electrophoretic deposition. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2009. [DOI: 10.1016/j.msec.2008.12.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Effects of biomimetically and electrochemically deposited nano-hydroxyapatite coatings on osseointegration of porous titanium implants. ACTA ACUST UNITED AC 2009; 107:782-9. [DOI: 10.1016/j.tripleo.2008.12.023] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2008] [Revised: 11/16/2008] [Accepted: 12/08/2008] [Indexed: 11/22/2022]
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25
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HUANG N, LENG Y, YANG P, WANG J, CHEN J, WAN G. Biomedical Applications of Plasma and Ion Beam Processing. ACTA ACUST UNITED AC 2008. [DOI: 10.3131/jvsj2.51.81] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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26
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Nagai N, Okauchi M, Rodriguez A, Gunduz M, Hu H, Kubota M, Nagaoka N, Inoue M, Nagatsuka H, Takagi T, Akao M. Development of New Titanium Coating Material (CaTiO3-aC) with Modified Thermal Decomposition Method. J HARD TISSUE BIOL 2008. [DOI: 10.2485/jhtb.17.47] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Kim KH, Kwon TY, Kim SY, Kang IK, Kim S, Yang Y, Ong JL. Preparation and Characterization of Anodized Titanium Surfaces and Their Effect on Osteoblast Responses. J ORAL IMPLANTOL 2006; 32:8-13. [PMID: 16526576 DOI: 10.1563/741.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
AbstractIn this study, titanium (Ti) surface was modified by anodizing with a mixture of β-glycerophosphate sodium and calcium (Ca) acetate, and the anodized surfaces were characterized by scanning electron microscopy, X-ray diffraction, and electron probe microanalysis. In vitro osteoblast response to anodized oxide was also evaluated. The anodic oxide produced was observed to have interconnected pores (0.5–2 μm in diameter) and intermediate roughness (0.60–1.00 μm). In addition, anodic oxide was observed to have amorphous and anatase oxide. Calcium and phosphorus ions were deposited on the Ti oxide during anodization. Osteoblast differentiation, as indicated by alkaline phosphatase production, was enhanced on anodized surfaces. It was thus concluded from this study that Ca phosphate can be deposited on Ti surfaces by anodization. It was also concluded that the phenotypic expression of osteoblast was enhanced by the presence of Ca phosphate and higher roughness on anodized Ti surfaces.
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Affiliation(s)
- Kyo-Han Kim
- Department of Dental Biomaterials, College of Dentistry, Institute of Biomaterials Research and Development, Kyungpook National University, Daegu, Korea
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Goyenvalle E, Aguado E, Nguyen JM, Passuti N, Le Guehennec L, Layrolle P, Daculsi G. Osteointegration of femoral stem prostheses with a bilayered calcium phosphate coating. Biomaterials 2005; 27:1119-28. [PMID: 16139882 DOI: 10.1016/j.biomaterials.2005.07.039] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2005] [Accepted: 07/21/2005] [Indexed: 11/16/2022]
Abstract
Our purpose was to evaluate the osteointegration of bilayered calcium phosphate (CaP)-coated femoral hip stems in a canine model. A first layer of hydroxyapatite (HA) 20 microm thick and a superficial layer of Biphasic Calcium Phosphate (BCP) 30 microm thick were plasma-sprayed on to the proximal region of sandblasted Ti6Al4V prostheses. Bilayered CaP-coated and non-coated canine femoral stems were implanted bilaterally under general anesthesia in 6 adult female Beagle dogs. After 6 and 12 months, a significant degradation of the bilayered coating occurred with a remainder of 33.1+/-12.4 and 23.6+/-9.2 microm in thickness, respectively. Lamellar bone apposition was observed on bilayered coated implants while fibrous tissue encapsulation was observed on non-coated femoral stems. The bone-implant contacts (BIC) were 91+/-3% and 81+/-8% for coated and 7+/-8% and 8+/-12% for non-coated implants, at 6 and 12 months, respectively. Our study supports the concept of a direct relationship between the biodegradation of CaP coating and the enhanced osteointegration of titanium prostheses. A bilayered CaP coating might therefore enhance bone apposition in the early stages because of the superior bioactivity of the BCP layer while the more stable HA layer might sustain bone bonding over long periods.
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Affiliation(s)
- Eric Goyenvalle
- INSERM EM 9903, Materials of Biological Interest, Faculty of Dental Surgery, BP 84215, 44042 Nantes Cedex 1, France
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An Investigation of Residual Stress of Porous Titania Layer by Micro-Arc Oxidation under Different Voltages. ACTA ACUST UNITED AC 2005. [DOI: 10.4028/www.scientific.net/msf.490-491.552] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The surface modification of titanium by micro-arc oxidation under different voltages was processed to achieve good direct oseointegration. The new technique of two-dimensional X-ray diffraction was used to measure the residual stress of the layer. The results show that a porous titania layer containing Ca and P is obtained by micro-arc oxidation. The pore size and Ca/P of the layer are affected by the voltage. The high voltage can induce forming CaTiO3. The residual stress under different voltage is compressive stress and increases with the improvement of the voltage.
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Vasudev DV, Ricci JL, Sabatino C, Li P, Parsons JR. In vivo evaluation of a biomimetic apatite coating grown on titanium surfaces. ACTA ACUST UNITED AC 2004; 69:629-36. [PMID: 15162404 DOI: 10.1002/jbm.a.30028] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Osteoconductive mineral coatings represent an established technology for enhancing the integration of orthopedic implants with living bone. However, current coatings have limitations related to fabrication methods, attachment strength to metal substrates, and in vivo performance. Low temperature biomimetic growth is a coating technique wherein the device to be coated is immersed in a meta-stable saturated solution of the coating constituents and growth of the coating is then allowed to proceed on the surface of the device. This study focused on the in vivo evaluation of a biomimetic apatite coating fabricated under these conditions. The experiment was designed to specifically test the amount of bone ingrowth into the coated channels versus the uncoated channels of an established bone chamber system, with emphasis placed on the amount of bone present on the coupon surface. Three types of measurements were taken on each channel: linear ingrowth %, area ingrowth %, and continuous bone apposition %. The experiments demonstrated that under controlled conditions, the apatite coating appears to resorb in 8 weeks and did stimulate early osseointegration with the metal surface with a reduction in fibrous tissue encapsulation. This coating may, therefore, be useful in facilitating early bone ingrowth into porous surfaces without the potential for coating debris, macrophage infiltration, fibrous tissue encapsulation, and eventual coating failure as may occur with current plasma-sprayed hydroxapatite coating techniques.
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Affiliation(s)
- Deepta Vani Vasudev
- Department of Orthopaedics, UMDNJ-New Jersey Medical School, 185 South Orange Avenue, MSB G-574, Newark, NJ 07103, USA
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Satsangi A, Satsangi N, Glover R, Satsangi RK, Ong JL. Osteoblast response to phospholipid modified titanium surface. Biomaterials 2003; 24:4585-9. [PMID: 12951001 DOI: 10.1016/s0142-9612(03)00330-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The objective of this study was to evaluate the effect of different phospholipid coatings on osteoblast responses in vitro. Commercially available phospholipids [phosphatidylcholine (PC), phosphatidyl-serine (PS) and phosphatidylinositol (PI)] were converted to their Ca-PL-PO(4) and were coated on commercially pure titanium (Ti) grade 2 disks. Using uncoated Ti surfaces as controls, cell responses to phospholipid-coated surfaces were evaluated using the American Type Culture Collection (Manassas, VA, USA) CRL-1486 human embryonic palatal mesenchyme cells (HEPM), an osteoblast precursor cell line, over a 14-day period. Total protein synthesis and alkaline phosphatase specific activity at 0, 7, and 14 days were measured. It was observed that Ti surfaces coated with PS exhibited enhanced protein synthesis and alkaline phosphatase specific activity compared to other phospholipids and uncoated surfaces. These results indicate the possible usefulness of PS-coated Ti surfaces for inducing enhanced bone formation and are very encouraging for bone and dental implantology.
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Affiliation(s)
- Arpan Satsangi
- Department of Restorative Dentistry, Division of Biomaterials, University of Texas Health Science Center, San Antonio, TX 78229, USA.
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Rodriguez R, Kim K, Ong JL. In vitro osteoblast response to anodized titanium and anodized titanium followed by hydrothermal treatment. J Biomed Mater Res A 2003; 65:352-8. [PMID: 12746882 DOI: 10.1002/jbm.a.10490] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In this study, Titanium (Ti) surfaces were modified using anodization. The electrolyte used for anodization was a mixture of calcium glycerophosphate and calcium acetate. The anodized surfaces were divided into three groups. Hydrothermal treatments were performed on two of the anodized groups for either 2 or 4 h. In vitro osteoblast response to anodized oxide and the hydrothermal treated oxide after anodization was evaluated in this study. Calcium and phosphorus ions were deposited on the Ti oxide during anodization. Anodized surfaces following a 4-h hydrothermal treatment were observed to promote the growth apatite-like crystals as compared with anodized surfaces after a 2-h hydrothermal treatment. Cellular function and onset of mineralization, as indicated by protein production and osteocalcin production, respectively, also were observed as enhanced on hydrothermal-treated surfaces. It was thus concluded from this study that calcium phosphate and apatite-like crystals could be deposited on Ti surfaces using anodization and a combination of anodization and hydrothermal treatment. It was also concluded that the phenotypic expression of osteoblast was enhanced by the presence of calcium phosphate or apatite-like crystals on anodized or hydrothermally treated Ti surfaces.
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Affiliation(s)
- R Rodriguez
- Department of Prosthodontics, Wilford Hall Medical Center, 2250 Pepperell Street, Lackland AFB, Texas 78236, USA
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MacDonald DE, Betts F, Stranick M, Doty S, Boskey AL. Physicochemical study of plasma-sprayed hydroxyapatite-coated implants in humans. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2001; 54:480-90. [PMID: 11426592 DOI: 10.1002/1097-4636(20010315)54:4<480::aid-jbm30>3.0.co;2-t] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This study represents the first report of the physical and chemical changes occurring in coatings of failed hydroxyapatite (HA)-coated titanium implants obtained from a comprehensive, multicenter human dental implant study. A total of 53 retrieved samples were obtained and compared with unimplanted controls with the same manufacturer and similar manufacture dates. Forty-five retrieved implants were examined for surface characteristics and bulk composition. Implants were staged based on implantation history: stage 1 (implants retrieved between surgical placement and surgical uncovering), stage 2 (implants retrieved at surgical uncovering and evaluation), stage 3 (implants retrieved between surgical uncovering evaluation and occlusal loading), and stage 4 (implants retrieved after occlusal loading). Scanning electron microscopy showed progressive coating thinning with implantation time. At later stages, bare Ti metal was detected by energy-dispersive X-ray analysis and electron spectroscopy for chemical analysis. Increases in Ti and Al (2-7.5 atm % each) were detected at the apical ends of all stage 4 samples. In unimplanted coatings, X-ray diffraction analysis demonstrated the presence of amorphous calcium phosphate, beta-tricalcium phosphate, tetracalcium phosphate, and calcium oxide in addition to large hydroxyapatite crystals (c axis size, D002 = 429 +/- 13 A; a axis size, D300 = 402 +/- 11 A, a/c aspect ratio 0.92). The nonapatitic phases disappeared with increased implantation time, although there was a persistence of amorphous calcium phosphate. Bulk coating chemical analysis showed that Ca/P ratios for implant controls (1.81 +/- 0.01) were greater than stoichiometric HA (1.67) and decreased for implant stages 3 and 4 (1.69 +/- 0.09 and 1.67 +/- 0.09, respectively), explained by the dissolution of the non apatitic phases. Crystal sizes also changed with implantation times, being smaller than the control at all but stage 4. Fourier transform infrared analyses agreed with these results, and also indicated the accumulation of bone (protein and carbonate-apatite) in the retrieved coatings. The accumulation of bone was not stage dependent. These findings indicate that there was some biointegration with the surrounding bone, but the greatest changes occurred with the HA coating materials, their loss, and chemical change.
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Affiliation(s)
- D E MacDonald
- Langmuir Center for Colloids and Interfaces, Columbia University, New York, New York 10027, USA.
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Lin FH, Liao CJ, Chen KS, Sun JS, Lin CY. Preparation of betaTCP/HAP biphasic ceramics with natural bone structure by heating bovine cancellous bone with the addition of (NH(4))(2)HPO(4). JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2000; 51:157-63. [PMID: 10825214 DOI: 10.1002/(sici)1097-4636(200008)51:2<157::aid-jbm3>3.0.co;2-r] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this study, the calcined bovine bone (CBB)-removing the organic substance by a burning process-with addition of different quantities of ammonium phosphate [(NH(4))(2)HPO(4)] (AP) was heated to a high temperature to transform its crystalline phase constitution from hydroxyapatite (HAP) into a tricalcium phosphate (TCP)/HAP biphasic structure. Results revealed that the CBB without AP appeared to be mainly composed of an HAP type pattern when heated to 1300 degrees C. After adding doped AP to CBB, the HPO(4)(2-) ions of AP condensed into P(2)O(7)(4-) ions at temperatures of 400-600 degrees C. P(2)O(7)(4-) ions reacted with the OH(-) ions of HAP to form betaTCP at temperatures up to 600 degrees C. The conversion reaction of HAP to betaTCP finished at around 900 degrees C. With increasing AP in the CBB, HAP gradually converted into different phase compositions of TCP/HAP or TCP at high temperature. Mechanical testing results showed that there was no significant difference in sintered CBB with different quantities of AP. By heating calcined bovine cancellous bone with different quantities of AP, we obtained different crystalline phase compositions of bioceramics with a natural porous structure.
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Affiliation(s)
- F H Lin
- Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
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35
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Abstract
In this work calcium phosphate (CaP) compounds with different PO(3-)(4)/HPO(2-)(4) R molar ratios in the 0.65-149 range were synthesized. In fact, all these CaPs contain different amounts of HPO(2-)(4) and PO(3-)(4) ions as well as the amorphous precursors (tricalcium phosphate and octacalcium phosphate) of hydroxyapatite deposition, which was shown by in vitro and in vivo measurements. Spectroscopical IR and Raman results showed the presence of bands whose intensity ratio can be related to the molar ratio R; in particular, the Raman I(962)/I(987) and the IR I(1035)/I(1125) intensity ratios were characterized as markers of the molar ratio. For these CaP compounds a nucleation model, which was based on the ability of HPO(2-)(4) ions to form strong H bonds with PO(3-)(4) ions, was proposed.
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Affiliation(s)
- P Taddei
- Dipartimento di Biochimica "G. Moruzzi," Sezione di Chimica e Propedeutica Biochimica, via Belmeloro 8/2, Università di Bologna, 40126 Bologna, Italy
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36
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Yamashita K, Yonehara E, Ding X, Nagai M, Umegaki T, Matsuda M. Electrophoretic coating of multilayered apatite composite on alumina ceramics. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2000; 43:46-53. [PMID: 9509343 DOI: 10.1002/(sici)1097-4636(199821)43:1<46::aid-jbm5>3.0.co;2-m] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
By means of an electrophoretic deposition technique followed by sintering, alumina and zirconia ceramics were coated with apatitic composites composed of porous surface and intermediate layers of hydroxyapatite and an adhesive calcium phosphate layer. The electrophoretic deposition of these layers was attained by the use of a mixed solvent of acetylacetone and alcohol as well as the mixed powders of the calcium phosphates and alumina. The adhesive layer was formed by the codeposition of calcium phosphate glass powders (Ca/P = 1/2) with hydroxyapatite, while the open porosity of the surface layer was increased with the addition of alumina to the hydroxyapatite layers. The resultant phases of sintered composite layers were tricalcium phosphate and alumina with a small amount of hydroxyapatite.
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Affiliation(s)
- K Yamashita
- Department of Industrial Chemistry, Tokyo Metropolitan University, Japan
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37
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Kim HM, Kim Y, Park SJ, Rey C, Lee HM, Glimcher MJ, Ko JS. Thin film of low-crystalline calcium phosphate apatite formed at low temperature. Biomaterials 2000; 21:1129-34. [PMID: 10817265 DOI: 10.1016/s0142-9612(99)00265-3] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Surface modification of biomaterials to improve biocompatibility without changing their bulk properties is desired for many clinical applications and has become an emerging technology in biomaterial research and industry. In the present study, a simple method of coating the solid surfaces of metals, organic tissue matrices, glasses, inorganic ceramics as well as organic polymers with a thin film of low-crystalline apatite crystals (LCA) was developed. Acidic solution containing calcium and phosphate ions was neutralized with alkaline solution to form calcium phosphate precipitates at low temperature. Precipitates of solid calcium phosphate particles were, then, removed by filtration. Concentration of free ions in the filtered ion solution which were not involved in the formation of calcium phosphate precipitate was high enough to induce the heterogeneous nucleation on the solid surfaces at low temperature. Thin layers of calcium phosphate crystals were formed on the surfaces of metals, glasses, inorganic ceramics, organic polymers including hydrophobic ones, and biological tissue matrices with this solution. The thin layer of crystals consisted of poorly crystalline calcium phosphate apatite crystals which contain high amount of labile ions like bone crystals and did not dissolve in the physiologic solutions. Various cells attached to this crystal layer and proliferated well.
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Affiliation(s)
- H M Kim
- Department of Oral Anatomy and Dental Research Institute, College of Dentistry, Seoul National University, South Korea
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38
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Haman JD, Chittur KK, Crawmer DE, Lucas LC. Analytical and mechanical testing of high velocity oxy-fuel thermal sprayed and plasma sprayed calcium phosphate coatings. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2000; 48:856-60. [PMID: 10556851 DOI: 10.1002/(sici)1097-4636(1999)48:6<856::aid-jbm14>3.0.co;2-i] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Plasma spraying (PS) is the most frequently used coating technique for implants; however, in other industries a cheaper, more efficient process, high-velocity oxy-fuel thermal spraying (HVOF), is in use. This process provides higher purity, denser, more adherent coatings than plasma spraying. The primary objective of this work was to determine if the use of HVOF could improve the mechanical properties of calcium phosphate coatings. Previous studies have shown that HVOF calcium phosphate coatings are more crystalline than plasma sprayed coatings. In addition, because the coatings are exposed to more complex loading profiles in vivo than standard ASTM tensile tests provide, a secondary objective of this study was to determine the applicability of four-point bend testing for these coatings. Coatings produced by HVOF and PS were analyzed by profilometry, diffuse reflectance Fourier transform infrared spectroscopy, X-ray diffraction, four-point bend, and ASTM C633 tensile testing. HVOF coatings were found to have lower amorphous calcium phosphate content, higher roughness values, and lower ASTM C633 bond strengths than PS coatings; however, both coatings had similar crystal unit cell sizes, phases present (including hydroxyapatite, beta-tricalcium phosphate, and tetracalcium phosphate), and four-point bend bond strengths. Thus, the chemical, structural, and mechanical results of this study, in general, indicate that the use of HVOF to produce calcium phosphate coatings is equivalent to those produced by plasma spraying.
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Affiliation(s)
- J D Haman
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama, USA.
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Liao CJ, Lin FH, Chen KS, Sun JS. Thermal decomposition and reconstitution of hydroxyapatite in air atmosphere. Biomaterials 1999; 20:1807-13. [PMID: 10509191 DOI: 10.1016/s0142-9612(99)00076-9] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In this paper, the decomposition and reconstruction behavior of hydroxyapatite (HAP) during heating and cooling in air atmosphere were studied. The commercial HAP were chosen and gradually heated to 1500 degrees C and cooled to room temperature by a program controlled SiC heated furnace. X-ray diffraction (XRD) and Fourier-transformed infrared (FTIR) analysis were used to investigate the change of crystalline phases and functional groups of HAP at different temperatures. Weight change of samples was recorded by thermogravimetric analysis (TGA) during heating and cooling. The results revealed that HAP gradually releases its OH- ions and transforms into OHAP in the temperature of 1000-1360 degrees C. Above 1360 degrees C, the OHAP would decompose into TTCP and alpha TCP phase. The OH- stretching bands of HAP could be traced by FTIR even at the temperature of 1350 degrees C which indicates HAP decomposition. HAP does not dehydrate completely before decomposition. We speculated that some oxyapatite (OAP) might be formed during dehydration with a great amount of OHAP still left in the system even up to the temperature of decomposition. In the temperature range of 1400-1500 degrees C, there was no significant difference in XRD patterns, only TTCP and alpha TCP crystalline phases were observed. When the HAP gradually cools from 1500 degrees C, a part of TTCP and alpha TCP would directly reconstruct into OAP around 1350 degrees C. OAP existed in the temperature range of 1350-1300 degrees C during cooling. When the temperature decreased to 1290 degrees C, a part of TTCP and alpha TCP reconstructed into OHAP by rehydration reaction and OAP were rehydrated into OHAP as well. At 1100 degrees C, the rest of TTCP and alpha TCP reconstitutes into HAP. As the temperature decreases, the OHAP is gradually rehydrated and reconstituted into HAP.
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Affiliation(s)
- C J Liao
- Institute of Biomedical Engineering, College of Medicine, National Taiwan University, Taipei, ROC
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40
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Ogiso M, Yamashita Y, Matsumoto T. Differences in microstructural characteristics of dense HA and HA coating. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1998; 41:296-303. [PMID: 9638535 DOI: 10.1002/(sici)1097-4636(199808)41:2<296::aid-jbm15>3.0.co;2-j] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Two implant types of hydroxyapatite (HA) currently are available for dental implants: dense HA-cemented titanium (Ti) and HA-coated. It has been shown in previous reports that there are differences in the chemical and mechanical stabilities between the dense HA and HA coated. The differences are thought to be due to structural differences between the two ceramic types. The aim of this study was to investigate the differences in microstructural characteristics of currently available dense HA and HA coated implants before implantation and at periods of 3 weeks and 10 months after implantation in canine bone. X-ray diffractometry, infrared analysis, transmission electron microscopy, and energy dispersive X-ray analysis were used. The dense HA is composed of crystal grains, with a well crystallized structure of HA, closely bound to each other and approximately 0.4-0.6 micron in size. Implantation did not change the original sintered structure of the dense HA. The HA coating was composed of an amorphous phase with a Ca/P ratio of 1.46 and a crystal phase consisting of oxyhydroxyapatite, tricalcium phosphate, tetracalcium phosphate, and CaO, with a Ca/P ratio of 1.57. In the amorphous phase, compared to other portions in the amorphous phase, there were some layers with lower atomic density and with no significant difference in Ca/P ratio. After implantation, the crystallization of super fine crystals of approximately 4-5 nm in thickness occurred in the amorphous phase, and with time it progressed and spread from the surface to the deeper portion of the HA coating. A Ca/P ratio of 1.58 in the crystallized portion was close to the ratio (1.60) in the dense HA, suggesting that the super fine crystals were HA. This crystallization cannot significantly decrease the solubility of the amorphous phase portion and poses risks of stress accumulation within the coating and a decrease of binding strength between the HA coating and the substrate.
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Affiliation(s)
- M Ogiso
- Department of Fixed Prosthodontics, Faculty of Dentistry, Tokyo Medical and Dental University, Japan
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41
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Abstract
Thermally processed hydroxyapatite coatings used on dental implants and hip prostheses for enhanced fixation may typically consist of a number of chemical and structural phases. These phases affect coating performance and tissue attachment. Hydroxyapatite was plasma sprayed to examine the phase evolution during processing. Coatings were examined with X-ray diffraction and elemental analysis. Results indicate that phase transformations are produced by (a) preferential removal of hydroxyl and phosphate leading to a change in melt composition, and (b) the high cooling rate due to the thermal spray process. Hydroxyl group removal promotes the amorphous phase and oxyapatite. Further heating produces a less viscous melt facilitating decomposition of hydroxyapatite to tricalcium and tetracalcium phosphate. Phosphate removal during flight produces a more calcium-rich melt preferring tetracalcium phosphate and calcium oxide formation. A proposed model shows the phase location within the lamellae of these coatings. Coating processes must thus prevent removal of hydroxide and phosphate during processing to maximize the hydroxyapatite content.
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Affiliation(s)
- K A Gross
- Department of Materials Science and Engineering, State University of New York at Stony Brook, 11794-2275, USA
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42
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Abstract
Thermally processed hydroxyapatite coatings used on dental implants and hip prostheses for enhanced fixation may typically consist of a number of chemical and structural phases. These phases affect coating performance and tissue attachment. Hydroxyapatite was plasma sprayed to examine the phase evolution during processing. Coatings were examined with X-ray diffraction and elemental analysis. Results indicate that phase transformations are produced by (a) preferential removal of hydroxyl and phosphate leading to a change in melt composition, and (b) the high cooling rate due to the thermal spray process. Hydroxyl group removal promotes the amorphous phase and oxyapatite. Further heating produces a less viscous melt facilitating decomposition of hydroxyapatite to tricalcium and tetracalcium phosphate. Phosphate removal during flight produces a more calcium-rich melt preferring tetracalcium phosphate and calcium oxide formation. A proposed model shows the phase location within the lamellae of these coatings. Coating processes must thus prevent removal of hydroxide and phosphate during processing to maximize the hydroxyapatite content.
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Affiliation(s)
- K A Gross
- Department of Materials Science and Engineering, State University of New York at Stony Brook, 11794-2275, USA
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43
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Hemmerl� J, �n�ag A, Ert�rk S. Ultrastructural features of the bone response to a plasma-sprayed hydroxyapatite coating in sheep. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/(sici)1097-4636(19970905)36:3<418::aid-jbm17>3.0.co;2-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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44
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Antonov EN, Bagratashvili VN, Popov VK, Sobol EN, Davies MC, Tendler SJ, Roberts CJ, Howdle SM. Atomic force microscopic study of the surface morphology of apatite films deposited by pulsed laser ablation. Biomaterials 1997; 18:1043-9. [PMID: 9239466 DOI: 10.1016/s0142-9612(97)00030-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Atomic force microscopy (AFM) has been used to study the surface morphology of apatite films deposited on metallic and polyethylene substrates by laser ablation using KrF and transversely excited atmospheric CO2 lasers. The films are found to consist of a smooth apatite coating with macroparticles scattered on the surface. A wide variety of macroparticles, differing in size, shape and roughness, were found and analysed employing the high spatial resolution of AFM (< 1 nm). We have investigated the correlation between the apatite film morphology and the deposition conditions. Of particular importance are laser fluence, gas pressure, the nature of the target and the substrate temperature. We have explained these dependencies on the basis of a theoretical model which includes evaporation and a cluster-type laser ablation mechanism.
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Affiliation(s)
- E N Antonov
- Research Center for Technological Lasers, Russian Academy of Sciences, Troitsk
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45
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Paschalis EP, Zhao Q, Tucker BE, Mukhopadhayay S, Bearcroft JA, Beals NB, Spector M, Nancollas GH. Degradation potential of plasma-sprayed hydroxyapatite-coated titanium implants. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1995; 29:1499-505. [PMID: 8600140 DOI: 10.1002/jbm.820291206] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The purpose of this study was to develop an analytical method for evaluating the dissolution behavior of plasma-sprayed hydroxyapatite (HAP) coatings. Six commercially available and clinically used coatings applied to nonporous titanium coupons according to their respective specifications for orthopedic devices were used in this study. Dissolution behavior was monitored by first preconditioning the implant in 0.15 mol L-1 sodium chloride solution at 37 degrees C until either equilibrium or the desired change in solution hydrogen and calcium ion concentrations had been reached. In the second step, the implants were subjected to dual constant composition (DCC) dissolution under conditions of controlled undersaturation. Results indicate that the dissolution rates of the HAP coatings may differ by as much as a factor of 5 despite the fact that analytical techniques, including X-ray diffraction and FTIR, indicate no change in crystallinity or composition of the coatings before and after the solution treatment. These results indicate that HAP coatings from different sources react very differently when placed in the same local aqueous environment. However, more work will be necessary before these in vitro results can be used to predict in vivo behavior.
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Affiliation(s)
- E P Paschalis
- Department of Chemistry, State University of New York at Buffalo 14214, USA
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46
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Ishizawa H, Fujino M, Ogino M. Mechanical and histological investigation of hydrothermally treated and untreated anodic titanium oxide films containing Ca and P. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1995; 29:1459-68. [PMID: 8582915 DOI: 10.1002/jbm.820291118] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In a previous study a new method for forming thin hydroxyapatite (HA) layers on titanium was described. Titanium was anodized at 350 V in an electrolyte solution containing sodium beta-glycerophosphate and calcium acetate, and an anodic titanium oxide film containing Ca and P (AOFCP) was formed on the surface. Then numerous HA crystals were precipitated on the AOFCP during hydrothermal treatment in high-pressure steam at 300 degrees C. In this study three types of hydrothermally treated films differing in amounts of precipitated HA crystals and tensile adhesive strength, and untreated films were histologically and mechanically investigated in a transcortical rabbit femoral model for 8 weeks of implantation using light microscopy, scanning electron microscopy (SEM), and push-out tests. Machined titanium and HA ceramics served as control materials. The push-out shear strength and bone apposition of the AOFCP significantly increased after hydrothermal treatment, and were equivalent to those of HA ceramics, although the HA layer on the AOFCP was thin at 1-2 microns. From SEM observation of the pushed-out specimen, it was found that the thin HA layer had directly bonded to bone but the AOFCP had not. The push-out strength of the hydrothermally treated film resulted from the chemical bonding of the bone-HA layer interface, while that of the untreated film resulted from mechanical interlocking force between bone and the microprojections. There was a small difference in bone apposition but no significant difference in push-out strength with the amount of precipitated HA crystals on the treated films. Among the treated films, the film formed at the lowest electrolyte concentration showed the lowest bone apposition because of incomplete covering by the HA crystals, and showed the highest stability against mechanical failure because the adhesive strength was very high at about 38 mPa. Also, the hydrothermally untreated anodic oxide films, whose surfaces were rough as a result of the large microprojections, showed much higher push-out strength and bone apposition than titanium. The good hard-tissue compatibility may be attributed to the surface roughness and the possible inhibition of titanium ion release from the specimen.
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Affiliation(s)
- H Ishizawa
- Department of Technological Development, Nikon Corporation, Kanagawa, Japan
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47
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Ishizawa H, Ogino M. Characterization of thin hydroxyapatite layers formed on anodic titanium oxide films containing Ca and P by hydrothermal treatment. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1995; 29:1071-9. [PMID: 8567705 DOI: 10.1002/jbm.820290907] [Citation(s) in RCA: 187] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
An anodic titanium oxide film containing Ca and P (AOFCP) was formed on commercially pure titanium which was anodized in an electrolytic solution of dissolved beta-glycerophosphate (beta-GP) and calcium acetate (CA). Hydroxyapatite (HA) crystals were precipitated by hydrothermally heating the AOFCP at 300 degrees C. After hydrothermal treatment, the film was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray microanalysis (EDX), and tensile tests. The morphology, composition, and amount of HA crystals precipitated were significantly affected by the composition of the electrolytes. Near-stoichiometric HA crystals with high crystallinity were precipitated completely covering the AOFCP surface at specific electrolyte concentrations. The HA layers were thin at 1-2 microns in thickness. The adhesive strength of the film increased with decreasing electrolyte concentration and the maximum value was about 40 MPa. In vitro tests for 300 days suggested that the stability of the film was high. The high adhesive strength may result from the AOFCP existing as an intermediate layer between the HA layer and a titanium substrate. The intervention of the AOFCP may have prevented abrupt changes in Ca and P content at an HA coating-titanium interface as seen in a plasma-sprayed one. The porous TiO2 matrix of the AOFCP may be suitable for nucleation sites of HA crystals, as well as SiO2 matrix of silicate bioactive glasses or glass ceramics.
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Affiliation(s)
- H Ishizawa
- Department of Technological Development, Nikon Corporation, Kanagawa, Japan
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48
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Roome CM, Adam CD. Crystallite orientation and anisotropic strains in thermally sprayed hydroxyapatite coatings. Biomaterials 1995; 16:691-6. [PMID: 7578772 DOI: 10.1016/0142-9612(95)99696-j] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Thermally sprayed hydroxyapatite powders and coatings have been studied using X-ray powder diffraction and scanning electron microscopy. Preferred orientation of the crystallites has been found on a number of coated plates using X-ray powder diffraction, and full profile fitting of the patterns from the extracted powders indicates anisotropically thermally strained crystallites. This is a result of rapid crystal regrowth and associated thermal gradients on deposition. Electron micrographs of some coatings show a consistent picture of columnar crystallites orientated perpendicular to the substrate surface.
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Affiliation(s)
- C M Roome
- Physics Division, School of Sciences, Staffordshire University, Stoke on Trent, UK
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49
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Weng J, Liu XG, Li XD, Zhang XD. Intrinsic factors of apatite influencing its amorphization during plasma-spray coating. Biomaterials 1995; 16:39-44. [PMID: 7718691 DOI: 10.1016/0142-9612(95)91094-f] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Hydroxyapatite coatings were prepared from differently treated starting powders to investigate the intrinsic factors of apatite influencing its amorphization during plasma-spray coating. The joint analyses of X-ray diffraction and infrared spectra show that the vacancies located on missing hydroxyl sites retard the amorphous/crystalline conversion and enforce retention of the amorphous component; the absorbed water molecules that pre-exist in the starting powder can be incorporated into the vacancies in the hydroxyapatite lattice during plasma-spray coating and compensate for the missing hydroxyls so as to promote the transformation of amorphous into crystalline apatite in the coating process. The more vacancies there are in the apatite structure due to missing hydroxyl sites, the more amorphous the component in the resultant coatings. Moreover, the amorphous phase formed in this way is stable in room conditions.
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Affiliation(s)
- J Weng
- Institute of Materials Science & Technology, Sichuan University, Chengdu, People's Republic of China
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50
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Knowles JC, Bonfield W. Development of a glass reinforced hydroxyapatite with enhanced mechanical properties. The effect of glass composition on mechanical properties and its relationship to phase changes. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1993; 27:1591-8. [PMID: 8113248 DOI: 10.1002/jbm.820271217] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Utilizing glasses of the types xNa2O-(1-x)P2O5 and xCaO-(1-x)P2O5 (where x = 0.2, 0.3, and 0.5), a systematic study of the effect of increasing network modifying oxides in glasses was made on the mechanical properties of a glass reinforced hydroxyapatite, at glass additions of 2.5 and 5 wt%. For the soda type glass, phase changes were promoted much more readily compared to the lime type glass. This was true for both 2.5 and 5 wt% additions of glass. For the lime type glass, considerable differences between the effects of 2.5 and 5 wt% additions were seen. At 5 wt%, the increased amount of liquid phase present promotes an increased level of phase inversion to alpha and beta tricalcium phosphate. At 2.5 wt%, a larger percentage of the HA remains stable at higher temperatures. Furthermore, the effect of the composition may be seen. As the mol% of network forming oxide increases, (i.e., the Ca/P ratio moves towards 1.67, (the ratio for HA) the HA remains more stable. This is seen in the maintenance of both the HA phase and also the enhanced mechanical properties.
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Affiliation(s)
- J C Knowles
- IRC in Biomedical Materials, Queen Mary and Westfield College, London, U.K
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