Acceleration and Deceleration of Bone-Like Crystal Growth on Ceramic Hydroxyapatite by Electric Poling

Yamashita, Kimihiro; Oikawa, and Noriyuki; Umegaki, Takao

doi:10.1021/cm9602858

Cited by 334 publications

(267 citation statements)

References 13 publications

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“…In contrast, the P-surface was surrounded with anions such as HPO [2][3][4] , HCO 3-, and Cl -, and decelerated the rate of crystal nucleation. 13) Figure 6 shows SEM images of a pore 0.5 mm from the 0-surface, N-surface, and P-surface of HA disks after immersion in SBF for 5 d. It was found that bone-like apatite crystals were observed only on the polarized disks and not observed on the non-polarized disks. Figure 7 shows SEM images of inside center pores' cross-sectional surface of non-polarized and polarized disks after immersion in SBF for 7 d. Bone-like apatite crystals were not observed on the non-polarized disks, while the inside pores of the polarized disks were covered with deposited crystals of bone-like apatite.…”

Section: Jcs Japanmentioning

confidence: 98%

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Electrovector effect on bone-like apatite crystal growth on Inside pores of polarized porous hydroxyapatite ceramics in simulated body fluid

Iwasaki

Tanaka

Nakamura

et al. 2008

J. Ceram. Soc. Japan

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Porous hydroxyapatite (HA) disks and blocks with interconnecting pores (pore size150 mm, interconnecting window size 30 mm, and porosity75) were polarized and bone-like apatite formations on the pore surfaces were investigated by immersion test using simulated body fluid (SBF) to estimate the electrovector effect in porous bodies. Thermally stimulated depolarization current (TSDC) measurements were used to estimate the stored charges of polarized porous HA disks and blocks as 11 and 7 mC cm -2 , respectively, demonstrating that both the porous disks and blocks were successfully polarized. After immersion in SBF for 14 d, bone-like apatite formations within the pores were observed in the polarized and non-polarized HA disks and blocks. Based on scanning electron microscopic (SEM) images of the pores located around the center of the disks and the blocks (inside-pores), formation of bone-like apatite was accelerated in the polarized HA compared with that in the non-polarized HA. Although the weight of the polarized and non-polarized porous HA increased linearly with immersion time regardless of shape, the rate of weight change of the polarized HA was greater than that of the non-polarized HA. It was demonstrated that the electric charges on the inside-pore surface of porous HA have a positive effect on the formation of bone-like apatite crystals.

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Section: Jcs Japanmentioning

confidence: 98%

“…13) Polarization of HA ceramics occurs due to proton migration, causing an inducement of a surface electric charge. 14)- 16) In the case of dense HA ceramics, we have confirmed that the polarized surface influences biomedical phenomena 17), 18) and promotes the formation of new bone tissue.…”

Section: Introductionmentioning

confidence: 99%

Electrovector effect on bone-like apatite crystal growth on Inside pores of polarized porous hydroxyapatite ceramics in simulated body fluid

Iwasaki

Tanaka

Nakamura

et al. 2008

J. Ceram. Soc. Japan

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“…The presence of surface charges on HA bioceramics was shown to have a significant effect on both in vitro and in vivo crystallization of biological apatite [336][337][338][339][340]. Furthermore, a growth of both biomimetic calcium orthophosphates and bones was found to be accelerated on negatively charged surfaces and decelerated at positively charged surfaces [340][341][342][343][344][345][346][347][348][349]. In addition, the electrical polarization of HA bioceramics was found to accelerate a cytoskeleton reorganization of osteoblastlike cells [350][351][352], extend bioactivity [353] and enhance bone ingrowth through the pores of porous HA implants [354].…”

Section: Electrical Propertiesmentioning

confidence: 99%

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2011

BIO

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In the late 1960's, a strong interest was raised in biomedical applications of ceramic materials (named bioceramics a little bit later). Bioceramics was initially used as reasonable alternatives to metals in order to increase their biocompatibility. However, within a short period, it has grown into a diverse class of biomaterials, presently including three essential types: relatively bioinert, bioactive (or surface reactive) and bioresorbable bioceramics. This review is limited to bioceramics prepared from calcium orthophosphates only, which belong to the categories of bioactive and bioresorbable compounds. There have been a number of important advances in this field during the past 30 -40 years. The research was shifted from an initial study on the develop-ment of bioinert bioceramics towards bioactive and bioresorbable bioceramics, and these different types of calcium orthophosphate bioceramics can be tuned through the structural and compositional control. At the turn of the millennium, a new concept of calcium orthophosphate bioceramics has been developed to promote a regeneration of bones. Current biomedical applications of calcium orthophosphate bioceramics include artificial replacements for hips, knees, teeth, tendons and ligaments, as well as repair for periodontal disease, maxillofacial reconstruction, augmenttation and stabilization of the jawbone, spinal fusion and bone fillers after tumor surgery. Potential future applications of calcium orthophosphate bioceramics are demonstrated in drug delivery systems, effective carriers of growth factors, bioactive peptides and/or various types of cells for tissue engineering purposes.

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“…This way the surface becomes increasingly negatively charged due to the -3e charge of PO4 groups. Experimentally, surfaces with net ionic charges are found to drive the HAP platelets growth kinetics [70] but are typically neglected in surface studies of HAP. Then the authors applied periodic boundary conditions and fully relaxed atomic positions.…”

Section: Computational Studies Of the Hydroxyapatite Nanostructures mentioning

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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Acceleration and Deceleration of Bone-Like Crystal Growth on Ceramic Hydroxyapatite by Electric Poling

Cited by 334 publications

References 13 publications

Electrovector effect on bone-like apatite crystal growth on Inside pores of polarized porous hydroxyapatite ceramics in simulated body fluid

Electrovector effect on bone-like apatite crystal growth on Inside pores of polarized porous hydroxyapatite ceramics in simulated body fluid

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Компьютерные Исследования Наноструктур Гидроксиапатита, Их Особенности И Свойства

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