High Specific Surface Area in Nanometric Carbonated Hydroxyapatite

Padilla, S.; Izquierdo‐Barba, Isabel; Vallet‐Regí, María

doi:10.1021/cm801626k

Cited by 67 publications

(50 citation statements)

References 17 publications

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“…In particular, the broad peak at 3317 cm −1 in the gellan, related to the hydroxyl groups of the glucopyranose ring with various degrees of hydrogen bonding [65], is shifted to 3351 cm −1 in the GL80-F scaffold. The bands at 1605 and 1412 cm −1 in the gellan, due to asymmetric and symmetric stretching vibrations of the carboxylate group, appear at 1621 and 1421 cm −1 , respectively, in the scaffold; the latter peak interferes with the contribution of the CO 2− 3 groups of the ceramic, which has signals at 1474, 1419 and 873 cm −1 [61]. The shift of the hydroxyl band was also observed in agarose-containing scaffolds.…”

Section: Resultsmentioning

confidence: 80%

Control of the pore architecture in three-dimensional hydroxyapatite-reinforced hydrogel scaffolds

Román

Cabañas

Peña

et al. 2011

Science and Technology of Advanced Materials

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Hydrogels (gellan or agarose) reinforced with nanocrystalline carbonated hydroxyapatite (nCHA) were prepared by the GELPOR3D technique. This simple method is characterized by compositional flexibility; it does not require expensive equipment, thermal treatment, or aggressive or toxic solvents, and yields a three-dimensional (3D) network of interconnected pores 300-900 µm in size. In addition, an interconnected porosity is generated, yielding a hierarchical porous architecture from the macro to the molecular scale. This porosity depends on both the drying/preservation technology (freeze drying or oven drying at 37• C) and on the content and microstructure of the reinforcing ceramic. For freeze-dried samples, the porosities were approximately 30, 66 and below 3% for pore sizes of 600-900 µm, 100-200 µm and 50-100 nm, respectively. The pore structure depends much on the ceramic content, so that higher contents lead to the disappearance of the characteristic honeycomb structure observed in low-ceramic scaffolds and to a lower fraction of the 100-200-µm-sized pores. The nature of the hydrogel did not affect the pore size distribution but was crucial for the behavior of the scaffolds in a hydrated medium: gellan-containing scaffolds showed a higher swelling degree owing to the presence of more hydrophilic groups.

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Section: Resultsmentioning

confidence: 80%

Control of the pore architecture in three-dimensional hydroxyapatite-reinforced hydrogel scaffolds

Román

Cabañas

Peña

et al. 2011

Science and Technology of Advanced Materials

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“…Such results can be explained by the drying step which was performed under vacuum. Indeed, Padilla et al [32] have shown that the hydroxyapatite surface area was very sensitive to the presence of CO 2 during the synthesis, which yields substitutions of CO 3 2-ions in the Hap structure, and to the drying and calcination treatments. Impregnation of Co species on the hydroxyapatite supports results in a decrease in specific surface area.…”

Section: Resultsmentioning

confidence: 99%

Calcium-Deficient and Stoichiometric Hydroxyapatites Promoted by Cobalt for the Catalytic Removal of Oxygenated Volatile Organic Compounds

et al. 2010

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Three series of hydroxyapatites (Hap) promoted by cobalt, have been synthesized using co-precipitation or impregnation methods, characterized by various techniques (XRD, UV-visible, Raman, and H 2 -TPR), and their catalytic properties were tested in the total oxidation of methanol. Characterization of the Co-promoted Hap solids showed that some Co 2? ions could incorporate the apatite structure and that bulk Co 3 O 4 entities could be formed outside the apatite grains. The activity for methanol oxidation of the cobalt-coprecipitated samples was low because structural cobalt ions are difficult to reduce, whereas the activity of the Co-impregnated samples was found to be very high since the methanol was totally converted at low temperature. This was related to the presence of Co 3 O 4 entities that are more easily reducible than structural Co ions and are found in higher quantity in the impregnated solids. This catalytic effect was highlighted using an Ca-deficient Hap as a support: cooperation of redox properties of Co 3 O 4 and acid properties of the apatite support led to a very efficient catalyst since the corresponding light-off temperature was lowered by 50°C with a catalyst containing 5 wt% of cobalt.

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“…The micron-sized calcium orthophosphate-based bioceramic powders suffer from poor sinterability, mainly due to a low surface area (typically 2 -5 m2/g), while the specific surface area of nanodimensional calcium orthophosphates exceeds 100 m2/g [146]. In addition, the resorption process of synthetic micron-sized calcium orthophosphates was found to be quite different from that of bone mineral [147].…”

Section: Micron-and Submicron-sized Calcium Orthophosphates Versus Thmentioning

confidence: 99%

Nanodimensional and Nanocrystalline Calcium Orthophosphates

Dorozhkin¹

2012

AJBE

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Nano-sized particles and crystals play an important role in the formation of calcified tissues of various animals. For example, nano-sized and nanocrystalline calcium orthophosphates in the form of apatites of biological origin represent the basic inorganic building blocks of bones and teeth of mammals. Namely, according the recent developments in biomineralization, tens to hundreds nanodimensional crystals of a biological apatite are self-assembled into these complex structures. This process occurs under a strict control by bioorganic matrixes. Furthermore, both a greater viability and a better proliferation of various types of cells have been detected on smaller crystals of calcium orthophosphates. Thus, the nano-sized and nanocrystalline forms of calcium orthophosphates have a great potential to revolutionize the hard tissue-engineering field, starting from bone repair and augmentation to controlled drug delivery systems. This review reports on current state of the art and recent developments on the subject, starting from synthesis and characterization to biomedical and clinical applications. Furthermore, the review also discusses possible directions for future research and development.

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High Specific Surface Area in Nanometric Carbonated Hydroxyapatite

Cited by 67 publications

References 17 publications

Control of the pore architecture in three-dimensional hydroxyapatite-reinforced hydrogel scaffolds

Control of the pore architecture in three-dimensional hydroxyapatite-reinforced hydrogel scaffolds

Calcium-Deficient and Stoichiometric Hydroxyapatites Promoted by Cobalt for the Catalytic Removal of Oxygenated Volatile Organic Compounds

Nanodimensional and Nanocrystalline Calcium Orthophosphates

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