Preparation and Structure Refinement of Monoclinic Hydroxyapatite

Ikoma, Toshiyuki; Yamazaki, Atsushi; Nakamura, Satoshi; Akao, Masaru

doi:10.1006/jssc.1998.8120

Cited by 108 publications

(83 citation statements)

References 16 publications

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“…It has specific structural features that define its basic physical properties, charge distribution and surface electric potential, which have especially important role for the living cells adhesion and proliferation [1][2][3]. 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%

“…Recent modeling and computational study of HAP structures, their specific surface properties and changes during the formation of various stoichoimetric HAP contents or possible defects [7,9], to determine the electric potential of the HAP surface charge density (polarization), is an important and necessary task for the study of these properties for HAP nanoparticles with various sizes and shapes [11]. It is also useful for creating of new HAP nanostructures having wide biomedical applications [13][14][15][16][17][18][19].…”

Section: Introductionmentioning

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%

“…Computer simulation was employed to understand the HAP NPs structural, electrical (dipole momentum and polarization -surface charges) properties by molecular mechanics (MM+, BIO CHARM, OPLS, etc.) and by quantummechanical semi-empirical (in PM3 parametrization) in restricted and unrestricted HartreeFock approximation (RHF and UHF) and by Density Functional Theory (DFT) methods using local density approximation (LDA), using local basis in AIMPRO codes [6,52,56,68] and generalized gradient approximation (GGA), using plane-wave in VASP codes [7]. Particularly, HAP optical properties based on the computed by these DFT methods data of electronic Density of States (DOS) and electronic work functions obtained, are described and analysed.…”

Section: Introductionmentioning

confidence: 99%

“…The surface charge σ = P creates the electric field Eel = σ/(2εε0) = P/(2εε0) ∼ (0.28-0.295) × 10 9 V/m, for ε = 1, where ε is the relative dielectric permittivity of the media, and ε0 = ε0 ≈ 8.85 × 10 −12 F/m. For our estimation we took the average value of ε = 10 (are several reports in HAP on ε from 5 up 15 [7,10,30,44]). In this case an electrical field exists inside the HAP NP must be: Eel ∼ (0.28 -0.30) × 10 8 V/m, appearing as a result of surface charges, which can shift all the NP energy levels, including the surface level and work function, and this shift must depended on the NP size values.…”

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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: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

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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Phenotype and gene expression pattern of osteoblast‐like cells cultured on polystyrene and hydroxyapatite with pre‐adsorbed type‐I collagen

Hanagata

Takemura

Monkawa

et al. 2007

J Biomedical Materials Res

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Hydroxyapatite and type-I collagen are major components of bone matrix. We compared phenotype and gene expression pattern of osteoblast-like cells cultured on HAp and HAp with pre-adsorbed type-I collagen from neutral solutions (HAp/NCs) with those of tissue culture grade polystyrene (TCPS) and TCPS with the collagen (TCPS/NCs). In initial cell attachment, the cells tensely spread on TCPS, while loosely spread on TCPS/NCs, HAp, and HAp/NCs. The levels of expressed integrin alpha2 and alpha5 subunits were not significantly different among any surfaces. Although the cells on HAp/NCs directly attached with the same collagen molecules as TCPS/NCs, mineralization was observed in only TCPS/NCs. The basal substrates (TCPS and HAp) greatly influenced osteoblast maturation even in the surfaces with pre-adsorbed collagen, since mineralization was induced by TCPS, but not by HAp. Gene expression pattern analyzed with DNA microarray also supported greater influence of basal substrates than pre-adsorbed collagen. In addition, comprehensive gene expression analyses revealed that HAp and HAp/NCs specifically up-regulated Ly6a and Tmem37 genes, while down-regulated Ifitm5 gene.

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Preparation and Structure Refinement of Monoclinic Hydroxyapatite

Cited by 108 publications

References 16 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

Phenotype and gene expression pattern of osteoblast‐like cells cultured on polystyrene and hydroxyapatite with pre‐adsorbed type‐I collagen

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