Structure and stability of hydroxyapatite: Density functional calculation and Rietveld analysis

Haverty, D.; Tofail, Syed A. M.; Stanton, Kenneth T.; McMonagle, J.B.

doi:10.1103/physrevb.71.094103

Cited by 137 publications

(106 citation statements)

References 25 publications

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“…Hydroxyapatite (HA) is also known for its electret properties [1], piezoelectricity [2][3][4] and pyroelectricity [3,5]. While electret properties mean that space charge can be introduced and/or dipoles can be aligned by means of an external electric field [4], piezo and pyroelectric properties indicate that hydroxyapatite is naturally polar, confirming a prediction made from quantum mechanical simulation [6]. Piezo-and pyroelectric nature of HA in its thick film form were also confirmed [2].…”

Section: Introductionsupporting

confidence: 56%

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Biomedical Sensing with Hydroxyapatite Ceramics in GHz Frequency Range

Korostynska

Gandhi

Mason

et al. 2013

KEM

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A.Al-Shamma'a@ljmu.ac.uk, e Tofail.Syed@ul.ie Keywords: Hydroxyapatite, GHz frequency range, biocompatible sensor, real-time pressure sensing in medical applications, piezoelectic and pyroelectric properties, powder and films.Abstract. Hydroxyapatite (HA) is a leading biocompatible material extensively used for bone implants as a porous ceramic graft and as a bioactive coating. Electrical characteristics of HA can be employed in implantable devices for real-time in vivo pressure sensor applications such as in knee or hip prosthesis. In particular, high piezo and pyroelectricity of HA, its polarisation by electron beam and selective adsorption of proteins on polarised domains indicate the potential for real-time biosensing applications of HA. For this purpose, a comprehensive understanding of the dielectric behaviour of different forms of HA over a frequency range relevant for biomedical sensing is critical. Such information for HA, especially its frequency dependent dielectric behaviour over the GHz range, is rare. To this end, we report on novel investigations of properties of HA in powder and film forms in the GHz frequency range.

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Section: Introductionsupporting

confidence: 56%

“…Hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ) is a leading biocompatible material that is extensively used for bone implants as a porous ceramic graft and as a bioactive coating. Hydroxyapatite (HA) is also known for its electret properties [1], piezoelectricity [2][3][4] and pyroelectricity [3,5].…”

Section: Introductionmentioning

confidence: 99%

Biomedical Sensing with Hydroxyapatite Ceramics in GHz Frequency Range

Korostynska

Gandhi

Mason

et al. 2013

KEM

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“…It has been theoretically shown that the monoclinic polymorph is energetically favored at low temperature [15,[32][33][34][35], with respect to the hexagonal one, the reversible transition between them occurring at 480.5 K in heating and at 477.5 K in the cooling process.…”

Section: The Monoclinic Settingmentioning

confidence: 99%

About the Genetic Mechanisms of Apatites: A Survey on the Methodological Approaches

2017

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Apatites are properly considered as a strategic material owing to the broad range of their practical uses, primarily biomedical but chemical, pharmaceutical, environmental and geological as well. The apatite group of minerals has been the subject of a huge number of papers, mainly devoted to the mass crystallization of nanosized hydroxyapatite (or carboapatite) as a scaffold for osteoinduction purposes. Many wet and dry methods of synthesis have been proposed. The products have been characterized using various techniques, from the transmission electron microscopy to many spectroscopic methods like IR and Raman. The experimental approach usually found in literature allows getting tailor made micro-and nano-crystals ready to be used in a wide variety of fields. Despite the wide interest in synthesis and characterization, little attention has been paid to the relationships between bulk structure and corresponding surfaces and to the role plaid by surfaces on the mechanisms involved during the early stages of growth of apatites. In order to improve the understanding of their structure and chemical variability, close attention will be focused on the structural complexity of hydroxyapatite (HAp), on the richness of its surfaces and their role in the interaction with the precursor phases, and in growth kinetics and morphology.

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“…It is also useful for creating of new HAP nanostructures having wide biomedical applications [13][14][15][16][17][18][19]. The results of these studies [7,9,11,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] allow us to clarify possible mechanisms of structural changes and electrical properties of HAP in the bulk crystal and on the crystal surface (electrical potential, charges and polarization). And this, in turn, will allow one to improve the efficiency of HAP interactions with the living bone cells (osteoblasts, osteoclasts, etc.)…”

Section: Introductionmentioning

confidence: 99%

“…The specific feature of HAP is that it has a selected direction of the formation of hydroxyl OH groups (inner OH-channels) along the c axis, which allows the transfer of protons along this axis under special conditions [4][5][6][7][8][9][10][11][12][13][14][15]. Special interest here is connected with the physical properties of the nanosized HAP clusters [12][13][14][15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Компьютерные Исследования Наноструктур Гидроксиапатита, Их Особенности И Свойства

Bystrov¹

2017

Math.Biol.Bioinf.

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Abstract. In this review paper the main approaches to modeling the hydroxyapatite (HAP) structures and first-principle calculations of their properties, pure and with various defects, are considered. First, the HAP nano-particles (NPs) and clusters peculiarities are described using different methods: molecular mechanical and quantum mechanical, especially semi-empirical such as PM3. Both approximations used here, namely, restricted Hartee-Fock (RHF) and unrestricted Hartee-Fock (UHF), are considered. The influence of the protons (hydrogens), contained in the surrounding medium (pH), on the formation of HAP nanoparticles of various sizes and shapes is considered and discussed. Second, the HAP crystal unit cells studies are considered on the basis of a density functional theory (DFT) modelling. The main peculiarities of both phases (hexagonal and monoclinic) are considered too, including their ordered and disordered substructures. One of the important aspects of the computer modeling of HAP is to build the models and consider various structural modifications of HAP (such as, vacancies of oxygen atoms and hydroxyl OH group, hydrogen interstitials and different substitutions of atoms in HAP unit cell), which allow explicitly creating and exploring the changes in the charges of HAP and the electrical potential on the HAP surface. HAP modifications are most close to biological HAP and therefore are necessary for implant medical applications and can create and functionalize HAP surface with most adhesive properties for living cells (osteoblasts, osteoclatst). This improves the HAP implant quality. Besides, it has recently been established that oxygen vacancy in HAP influences their photo-catalytic properties. It is important for HAP usage as in environmental remediation and for bacteria inactivation. Therefore it is very important to create and investigate the oxygen vacancy models in HAP, and others defects models. In this work we review a DFT modelling and studies of HAP, both pure perfect bulk and imperfect bulk cases. Special HAP modelling approaches are used for layered slab super-cells units, which include vacuum spaces between the layered slabs forming HAP surface. To all these computer studies the first principle calculations were applied. In this review various DFT approximations are analysed for bulk and surface modified HAP. These approximations are carried out using both the local basis (local density approximation -LDA, in AIMPRO codes) and the plane-waves (generalized gradient approximation -GGA, in VASP codes). Data of all structures and models of HAP defects investigated are widely analyzed.

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Structure and stability of hydroxyapatite: Density functional calculation and Rietveld analysis

Cited by 137 publications

References 25 publications

Biomedical Sensing with Hydroxyapatite Ceramics in GHz Frequency Range

Biomedical Sensing with Hydroxyapatite Ceramics in GHz Frequency Range

About the Genetic Mechanisms of Apatites: A Survey on the Methodological Approaches

Компьютерные Исследования Наноструктур Гидроксиапатита, Их Особенности И Свойства

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