Apatite formation on organic monolayers in simulated body environment

Sato, Kimiyasu; Kumagai, Yuri; Tanaka, Junzo

doi:10.1002/(sici)1097-4636(200004)50:1<16::aid-jbm3>3.0.co;2-g

Cited by 117 publications

(68 citation statements)

References 7 publications

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“…However, the XRD pattern recorded in this study matches findings from others using biomimetic solution chemistry techniques. 13,32,33 The calcium silicate glass used in the nucleating phase played an important role in initiating HAp deposition on the collagen substrate because, with no glass in the nucleating solution, HAp deposition failed to occur even after soaking in the growth solution for 11 days. These findings support the work of Kokubo,4 who suggested that the process initiating HAp deposition is via a silanol mechanism.…”

Section: Discussionmentioning

confidence: 99%

Collagen–hydroxyapatite composite prepared by biomimetic process

Lickorish¹,

Ramshaw²,

Werkmeister³

et al. 2003

J Biomedical Materials Res

172

105

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Abstract:A novel bone graft substitute comprising a porous, collagenous scaffold was biomimetically coated with hydroxyapatite using a simulated body fluid solution chemistry method. The scaffold had a porosity of approximately 85%, with pore sizes between 30 m and 100 m. Glutaraldehyde vapor was used to stabilize the collagenous scaffold, giving a significantly increased thermal stability over an unstabilized scaffold, as shown by differential scanning calorimetry. A thin layer (Ͻ10 m) of crystalline hydroxyapatite was deposited onto the stabilized collagenous scaffold by soaking the collagenous construct in simulated body fluid in the presence of calcium silicate glass. The presence of crystalline hydroxyapatite was confirmed by X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. In vitro cytotoxicity testing of the composite construct using L-929 fibroblasts (ISO 10993-5) and rabbit periosteal cells revealed a cytocompatible material that supported cellular attachment and proliferation.

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Section: Discussionmentioning

confidence: 99%

Collagen–hydroxyapatite composite prepared by biomimetic process

Lickorish¹,

Ramshaw²,

Werkmeister³

et al. 2003

J Biomedical Materials Res

172

105

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“…In our previous works, organic monolayer lms prepared by the Langmuir Blodgett (LB) method were used to investigate the nucleation mechanism of HAp crystals in a body environment. 7), 8) The LB lms with the same functional groups as collagen (i.e., carboxyl groups and amino groups) were placed in a simulat ed body environment. It was shown that crystallization of HAp was induced by the chemical interaction between carbox yl groups and inorganic ions in a body uid.…”

Section: )4)mentioning

confidence: 99%

“…The procedure used in the experiment is the same as described previously. 7), 8) The surface topography of the formed crystals was investigated using an SEM (S4500, Hitachi) operated at 5 kV.…”

Section: )4)mentioning

confidence: 99%

In-Situ IR Spectral Measurement in Organic Matrix-Mediated Hydroxyapatite Formation

Sato

Kumagai

Ikoma

et al. 2005

J. Ceram. Soc. Japan

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L@}gbNXU±ÉaeénChLVAp^Cg`¬ßöÉ¨¯éÔOªõ»Ìêªè ²¡ö×EFJF¢Þ E ¶îrVÞ Þ EnLiEcOÞ Þ YAEZp¤C4638560 ¤m §¼Ã®sçRaeºui¡´226698 Þ ÈwZpU»@\ CRESTC3320012 éÊ §ìûs{¬ 418 Þ Þ¿EÞ¿¤@\C3050044 ïé §ÂÎsÀØ 11Organic templatedirected crystallization of hydroxyapatite (HAp) was studied insitu via Fourier transform IR external reection spectroscopy. Langmuir monolayer of arachidic acid was formed on a surface of simulated body uid, which possesses inorganic ion concentrations and a pH value almost equal to those of human blood plasma. Owing to the chemical interactions between inorganic ions and carboxyl groups, heterogeneous nuclea tion of HAp occurred below the monolayer. The absorbances of the antisymmetric and symmetric methylene stretching bands in the IR spectra varied during the nucleation process, which means that conformational change of hydrocarbon chain occurred. Interfacial interactions between organic templates and induced crystals are often discussed only through static experimental models. However, the organic matrices should also be treated as elas tic template and their structural changes due to the formation of HAp crystals should be recognized, when the biomineralization mechanism is discussed.

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“…About 80 wt % of the total citrate in the body is accumulated in bone. Carboxylate groups are key for regulating the formation of apatite, 5,25 and citrate in bone provides more carboxylate groups than all the proteins other than collagen taken together. In vitro studies have shown that citrate at higher concentrations results in smaller HAp nanocrystals.…”

Section: ' Introductionmentioning

confidence: 99%

Biomimetic Self-Assembling Copolymer−Hydroxyapatite Nanocomposites with the Nanocrystal Size Controlled by Citrate

Liu

et al. 2011

Chem. Mater.

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Citrate binds strongly to the surface of calcium phosphate (apatite) nanocrystals in bone and is thought to prevent crystal thickening. In this work, citrate added as a regulatory element enabled molecular control of the size and stability of hydroxyapatite (HAp) nanocrystals in synthetic nanocomposites, fabricated with selfassembling block copolymer templates. The decrease of the HAp crystal size within the polymer matrix with increasing citrate concentration was documented by solid-state nuclear magnetic resonance (NMR) techniques and wide-angle X-ray diffraction (XRD), while the shapes of HAp nanocrystals were determined by transmission electron microscopy (TEM). Advanced NMR techniques were used to characterize the interfacial species and reveal enhanced interactions between mineral and organic matrix, concomitant with the size effects. The surface-to-volume ratios determined by NMR spectroscopy and long-range 31P{1H} dipolar dephasing show that 2, 10, and 40 mM citrate changes the thicknesses of the HAp crystals from 4 nm without citrate to 2.9, 2.8, and 2.3 nm, respectively. With citrate concentrations comparable to those in body fluids, HAp nanocrystals of sizes and morphologies similar to those in avian and bovine bones have been produced. KeywordsBiocompatibility, bioinspired materials, bone, crystal control, hybrid materials, nuclear magnetic resonance ' INTRODUCTIONBone, the primary supporting and protective organ of the mammalian body, is a nanocomposite of nanosized carbonated apatite crystals and the fibrous protein collagen (ca. 40 vol % each), with smaller contributions from other proteins and water. 1À5 The integration of the stiff apatite nanocrystals within the tough collagen fibers renders bone lightweight yet strong and tough. Human bone undergoes constant dynamic remodeling to repair fatigue damage, such as microcracks induced by stress. 6 However, when the damage is beyond the self-restoring ability of bone and severely compromises the quality of life especially in the elderly, therapeutic approaches to regenerate the mineralized tissues are desired. Ideal materials employed in tissue repair therapies should exhibit structural features similar to those in bone, be biocompatible, biodegradable, and bioactive.Various strategies of tissue engineering have been developed in recent years.7 Cell-or protein-based methods simulate the mineralization process in bone, 8À11 but the limited availability of materials, immunogenic responses, potential disease transmission, or interference with the therapeutic process curtails their application.7 Nonproteinaceous biopolymers, including cellulose, chitosan, and gelatin, have been also employed, but these have fewer apatite-nucleating functional groups such as carboxylate or phosphate moieties, and their properties are not readily tunable. Therefore, the use of synthetic polymers has been an attractive option to provide a scaffold for apatite formation and introduce apatite nucleating reagents. Polymers or polypeptides with acidic groups are favo...

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Apatite formation on organic monolayers in simulated body environment

Cited by 117 publications

References 7 publications

Collagen–hydroxyapatite composite prepared by biomimetic process

Collagen–hydroxyapatite composite prepared by biomimetic process

In-Situ IR Spectral Measurement in Organic Matrix-Mediated Hydroxyapatite Formation

Biomimetic Self-Assembling Copolymer−Hydroxyapatite Nanocomposites with the Nanocrystal Size Controlled by Citrate

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