Surface modification of hydroxyapatite. Part II. Silica

Borum, L; Wilson, Otto C.

doi:10.1016/s0142-9612(03)00240-0

Cited by 153 publications

(101 citation statements)

References 36 publications

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“…There are detailed reports on the infrared spectra, including assignment of the major bands for HAP [1][2][3]15], ACP [13,15] and DCPD [18]. Overall, the infrared spectra obtained in the present study were comparable with the literature reports for these compounds.…”

Section: Ftir Analysis Of Mdcp Hapsupporting

confidence: 86%

“…2-4). HAP nanoparticles have been reported to aggregate or agglomerate in aqueous suspensions to form microscale clusters, and this has created problems in the processing and the use of nanophase HAP-based materials [1,3]. In fact, there have been extensive studies on the modification of the surface properties of HAP to improve its suspension stability [1-3, 11, 12].…”

Section: Particle Size Changes Of Mdcp Suspensions In Water and Milk mentioning

confidence: 99%

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Stability of milk-derived calcium phosphate suspensions

Anema

2009

Dairy Sci. Technol.

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-Milk-derived calcium phosphate (MDCP) can be isolated from whey derived from acid casein or cottage cheese manufacture as a precipitated calcium phosphate material. However, the composition and suspension properties of this MDCP material are poorly understood. This study was aimed at examining the properties of MDCP when in suspension, and the factors affecting the stability of this calcium phosphate suspension. When suspended in water, MDCP aggregated, with the aggregation rate increasing with increasing temperature. Aggregation was more rapid in milk permeate than in water. The aggregation of MDCP increased with increasing ionic strength, and, as this was accompanied by a decrease in the magnitude of the ζ-potential, this could be explained by the effects of the electrolyte concentrations on the electrical double layers of the particles. Soluble calcium markedly increased the rate of aggregation of the MDCP, whereas soluble phosphate slightly retarded the aggregation. Soluble calcium changed the ζ-potential from negative to positive, with the particles becoming progressively more positive at higher soluble calcium levels. In contrast, increasing soluble phosphate levels made the ζ-potential of MDCP particles markedly more negative. These results indicate that the addition of soluble calcium or soluble phosphate had more specific effects, probably binding to the surface of the MDCP particles. The increased rate of aggregation in soluble calcium solutions could not be solely explained by the changes to the ζ-potentials of the particles. Article published by EDP Sciences Résumé -Stabilité de suspensions de phosphate de calcium dérivé de lait. Du phosphate de calcium d'origine laitière (PCL) peut être isolé à partir de lactosérum provenant de la fabrication de caséine acide ou de fromage Cottage sous forme de phosphate de calcium précipité. Cependant, la composition et les propriétés de suspension de ce PCL sont peu connues. Le but de cette étude était d'examiner les propriétés du PCL en suspension et les facteurs affectant la stabilité de cette suspension de phosphate de calcium. En suspension dans l'eau, le PCL s'agrégeait, et ce, d'autant plus que la température augmentait. L'agrégation était plus rapide dans le perméat de lait que dans l'eau. L'agrégation de PCL augmentait quand la force ionique augmentait, et, comme ceci s'accompagnait d'une diminution de magnitude du potentiel zeta, ce phénomène pourrait s'expliquer par les effets des concentrations en électrolyte sur les doubles couches électriques des particules. Le calcium soluble augmentait nettement le taux d'agrégation du PCL alors que le phosphate soluble retardait légèrement l'agrégation. Le calcium soluble faisait passer le potentiel zeta de négatif en positif, les particules devenant progressivement plus positives aux taux de calcium soluble plus élevés. Au contraire, l'augmentation des taux de phosphate soluble rendait le potentiel zeta des particules de PCL nettement plus négatif. Ces résultats indiquent que l'addition de calcium solubl...

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Section: Ftir Analysis Of Mdcp Hapsupporting

confidence: 86%

Section: Particle Size Changes Of Mdcp Suspensions In Water and Milk mentioning

confidence: 99%

Stability of milk-derived calcium phosphate suspensions

Anema

2009

Dairy Sci. Technol.

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“…During all the evaluated periods it was possible to observe a higher number of fibroblasts, osteobalsts, osteocytes and osteoclasts around and inside the implant when compared to the other groups. Silica plays a fundamental role in certain bioactive glasses, it is capable of osteoprogenitor cells induction in the lesion area 10,19 . The success of the castor polymer containing 10% silica may be attributed to the fact that silica, beyond the inductive properties, can promote great roughness, observed through the SEM.…”

Section: Resultsmentioning

confidence: 99%

Castor oil polyurethane containing silica nanoparticles as filling material of bone defect in rats

Nacer¹,

Poppi²,

Carvalho³

et al. 2012

Acta Cir. Bras.

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PURPOSE: To evaluate the biologic behavior of the castor polymer containing silica nanoparticles as a bone substitute in diafisary defect. METHODS: Twenty seven male rattus norvegicus albinus wistar lineage were submitted to bone defect filled with castor oil polymer. Three experimental groups had been formed with nine animals each: (1) castor oil polymer containing only calcium carbonate; (2) castor oil polymer with calcium carbonate and doped with 5% of silica nanoparticles; (3) castor polymer with calcium carbonate doped with 10% of silica nanoparticles; 3 animals of each group were submitted to euthanasia 15, 30 and 60 days after experimental procedure, and their femurs were removed to histological evaluation. RESULTS: there was bone growth in all the studied groups, with a greater tendency of growth in the group 1. After 30 days all the groups presented similar results. After 60 days a greater amount of fibroblasts, osteoblasts, osteocytes and osteoclasts in group 3 was observed, with integrated activity of 3 kinds of cells involved in the bone activation-reabsorption-formation. CONCLUSIONS: The castor polymer associated to the silica nanoparticles is biocompatible and allows osteoconduction. The presence of osteoprogenitors cells suggests silica osteoinduction capacity.

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“…Já o papel da sílica é inquestionável. A sílica desempenha um papel importante na biomineralização de muitos organismos, inclusive dos corais 72 . Hench et al 73 avaliaram a inflluência da sílica na bioatividade do Bioglass ® .…”

Section: Fatores Que Afetam a Bioatividade Do Materialsunclassified

Cerâmicas bioativas: estado da arte

Andrade

Domingues

2006

Quím. Nova

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Recebido em 13/10/04; aceito em 27/4/05; publicado na web em 24/8/05 BIOACTIVE CERAMICS: STATE OF THE ART. Bioactive glasses undergo corrosion with leaching of alkaline ions when exposed to body fluids. This results in the spontaneous formation of a layer of hydroxyapatite (HA) , the mineral component of natural bone, which in turn can induce bone growth in vivo. This paper describes the different types of bioactive glasses, the characterization methods currently used, and the main factors that influence their bioactivity. Nucleation and crystallization, the main mechanisms involved in the formation of hydroxyapatite, Ca 10 (PO 4 ) 6 (OH) 2, are discussed as a function of the chemical composition and the reactivity of the surface of the material. Finally, promising applications are considered.Keywords: sol-gel; bioactive glass; in vitro tests. INTRODUÇÃOO aprimoramento técnico-científico na área médica faz-se necessário devido à busca incansável do ser humano pela longevidade e por padrões de vida superiores, o que gera a necessidade de alternativas para reparo e substituição de tecidos vivos vitimados por traumas, patologias e fraturas, dentre outros 1 . Devido a problemas como disponibilidade limitada, dificuldade de armazenamento e um tempo cirúrgico maior dos enxertos autógenos e alógenos, os pesquisadores buscam materiais sintéticos que facilitem a reparação óssea visando o restabelecimento rápido das funções fisiológicas 2 . Dentre os materiais sintéticos usados para biorreparação do tecido ósseo, as cerâmicas, também conhecidas como biocerâmicas, são as mais empregadas. As biocerâmicas apresentam-se na forma de pós, revestimentos ou próteses usados para reparo, aumento ou substituição de tecidos doentes ou danificados, como ossos, juntas e dentes 3,4 . Embora muitas composições de cerâmicas tenham sido testadas para uso médico, poucas são usadas clinicamente. Destas, pode-se citar a Al 2 O 3 e ZrO 2, usadas, inicialmente, na substituição total de juntas dos quadris e fêmur; os fosfatos de cálcio usados como revestimento de ligas metálicas e em formato de granulados ou de pequenas peças porosas para reparo ósseo; os vidros e vitrocerâmicas bioativos usados para substituição e reparo de ossículos do ouvido interno, dentes e vértebras 3,5 . CERÂMICAS BIOATIVAS (CBAs)Atualmente, o uso de cerâmicas bioativas como implantes ósse-os tem sido muito estudado. O termo bioatividade foi usado primeiro para descrever a habilidade que certas composições de vidros, desenvolvidos no fim da década de 60 e início da de 70 6 , têm de se ligarem ao tecido ósseo circundante ao implante, induzindo a formação de uma camada de hidroxiapatita (HA) em sua superfície. Hoje, sabe-se que outros materiais cerâmicos como a HA sintética, o fosfato tri-cálcio sinterizado e algumas vitro-cerâmicas 7-11 também podem ser bioativos sob certas condições de síntese.Sabe-se que a superfície de uma cerâmica bioativa (CBA) induz a biomineralização do fosfato de cálcio (HA) através da interação com o plasma sanguíneo, que é a primeira fase que int...

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Surface modification of hydroxyapatite. Part II. Silica

Cited by 153 publications

References 36 publications

Stability of milk-derived calcium phosphate suspensions

Stability of milk-derived calcium phosphate suspensions

Castor oil polyurethane containing silica nanoparticles as filling material of bone defect in rats

Cerâmicas bioativas: estado da arte

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