A Computational Study of the Properties and Surface Interactions of Hydroxyapatite

Bystrov, Vladimir; Paramonova, Ekaterina; Costa, Maria Elisabete V.; Santos, Catarina; Almeida, Margarida; Kopyl, Svitlana; Dekhtyar, Yu.; Bystrova, Anna; Maevsky, E.I.; Pullar, Robert C.; Kholkin, A. L.

doi:10.1080/00150193.2013.822774

Cited by 22 publications

(30 citation statements)

References 5 publications

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“…As it was shown in [32,35] for these calculations, necessary precision is attained for the valence configuration of the Ca atom model with 2 electrons -(4s 2 ) shell. The calculated equilibrium HAP unit cell parameters were a = b = 9.4732 Å and c = 6.9989 Å for pure hexagonal P63/m phase, and a = 18.950 Å, b = 6.997 Å, c = 9.474 Å for pure monoclinic P21/b phase.…”

Section: Infinite Periodical Lattice and Electrical Potentialmentioning

confidence: 99%

“…It is important to note that for such ideal crystallographic structures the relation of atoms Ca and P must correspond strictly to the correct stoichiometry, with a ratio of Ca/P of 1.67 [1,5,35]. In a real mineral there could be many deviations from such ideal structures, including such defects as various vacancies, interstitials and replacements of several atoms [32,35]. Computational study allows us to construct similar ideal and defective HAP structures, though depending on the computational methods used.…”

Section: Formation Of Hap Crystal From Hap Nps In Various Conditionsmentioning

confidence: 99%

“…Naturally, HAP is a mineral form of calcium apatite with the formula Ca5(PO4)3(OH), but it is often written as Ca10(PO4)6(OH)2 to denote that the crystal unit cell comprises two molecular units. The specific feature of HAP is that the OH − ions form inner channels along the c axis with various random OH-dipoles orientations under different external conditions, which allow the transfer of protons along this axis under special conditions (such as temperature heating and applied electric field with necessary critical values) [28][29][30][31][32]35]. Usually HAP has 2 main different forms of nano-crystalline structures (in hexagonal P63/m and monoclinic P21/b space group structures) and amorphous structure.…”

Section: Formation Of Hap Crystal From Hap Nps In Various Conditionsmentioning

confidence: 99%

“…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%

“…Beyond HAP crystal bulk model, a special HAP model of the layered slab supercells units, which includes vacuum spaces between the layered slabs forming HAP surface, are considered and analysed too [5]. More computational details are described in [22,24,26,27,[30][31][32][33][34][35]67] and in sections below.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Infinite Periodical Lattice and Electrical Potentialmentioning

confidence: 99%

Section: Formation Of Hap Crystal From Hap Nps In Various Conditionsmentioning

confidence: 99%

Section: Formation Of Hap Crystal From Hap Nps In Various Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Компьютерные Исследования Наноструктур Гидроксиапатита, Их Особенности И Свойства

Bystrov¹

2017

Math.Biol.Bioinf.

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Electrical Functionalization and Fabrication of Nanostructured Hydroxyapatite Coatings

Bystrov

Bystrova

Dekhtyar

et al. 2019

Bioceramics and Biocomposites

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Water at hydroxyapatite surfaces: the effect of coverage and surface termination as investigated by all-electron B3LYP-D* simulations

et al. 2016

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A Computational Study of the Properties and Surface Interactions of Hydroxyapatite

Cited by 22 publications

References 5 publications

Компьютерные Исследования Наноструктур Гидроксиапатита, Их Особенности И Свойства

Компьютерные Исследования Наноструктур Гидроксиапатита, Их Особенности И Свойства

Electrical Functionalization and Fabrication of Nanostructured Hydroxyapatite Coatings

Water at hydroxyapatite surfaces: the effect of coverage and surface termination as investigated by all-electron B3LYP-D* simulations

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