Crystallization behavior of nanodisperse phases

Мелихов, И. В.

doi:10.1007/bf02757933

Cited by 8 publications

(3 citation statements)

References 9 publications

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“…Hence, the process of the formation of HAP in a precipitation reaction from a pure solution can be divided to following stages 178 : (i) homogeneous nucleation; (ii) aggregation of primary amorphous CAP particles into typically spherical units; (iii) aggregation of spheres into chain-like structures; (iv) growth of these structures; (v) secondary precipitation and phase transformation. The initially precipitated particles of the amorphous phase were observed to be round-shaped with 20-30 nm in size (although they can reach 120 nm in size), 179 but composed of smaller particles of 4 nm in size on average. It was also observed that an increase in the ripening time implied aggregation of spherical singlets and formation of needle-shaped CAP particles of about 20 nm in length.…”

Section: Mechanism Of Formation Of Hap By Precipitationmentioning

confidence: 97%

Nanosized hydroxyapatite and other calcium phosphates: Chemistry of formation and application as drug and gene delivery agents

2010

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The first part of this review looks at the fundamental properties of hydroxyapatite (HAP), the basic mineral constituent of mammalian hard tissues, including the physicochemical features that govern its formation by precipitation. A special emphasis is placed on the analysis of qualities of different methods of synthesis and of the phase transformations intrinsic to the formation of HAP following precipitation from aqueous solutions. This serves as an introduction to the second part and the main subject of this review, which relates to the discourse regarding the prospects of fabrication of ultrafine, nanosized particles based on calcium phosphate carriers with various therapeutic and/or diagnostic agents coated on and/or encapsulated within the particles. It is said that the particles could be either surface-functionalized with amphiphiles, peptides, proteins, or nucleic acids or injected with therapeutic agents, magnetic ions, or fluorescent molecules. Depending on the additive, they could be subsequently used for a variety of applications, including the controlled delivery and release of therapeutic agents (extracellularly or intracellularly), magnetic resonance imaging and hyperthermia therapy, cell separation, blood detoxification, peptide or oligonucleotide chromatography and ultrasensitive detection of biomolecules, and in vivo and in vitro gene transfection. Calcium phosphate nanoparticles as carriers of therapeutic agents that would enable a controlled drug release to treat a given bone infection and at the same be resorbed in the body so as to regenerate hard tissue lost to disease are emphasized hereby as one of the potentially attractive smart materials for the modern medicine.

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Section: Mechanism Of Formation Of Hap By Precipitationmentioning

confidence: 97%

Nanosized hydroxyapatite and other calcium phosphates: Chemistry of formation and application as drug and gene delivery agents

2010

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“…After these pioneering works several researchers found evidences that strongly support an aggregation mechanism to explain HA formation. The mechanism proposed by Melikhov [145] can be divided into the following steps: (i) homogeneous nucleation of ACP; (ii) aggregation of primary ACP particles into typically spherical units; (iii) aggregation of spheres into chain-like structures; (iv) growth of these structures; (v) secondary precipitation and phase transformation. The initially precipitated particles of the amorphous phase were observed to be round-shaped with 20-30 nm in size (although they can reach 120 nm in size) [145], but composed of smaller particles of 4 nm in size on average.…”

Section: Crystallization Mechanisms Of Nanocrystalline Apatitesmentioning

confidence: 99%

“…The mechanism proposed by Melikhov [145] can be divided into the following steps: (i) homogeneous nucleation of ACP; (ii) aggregation of primary ACP particles into typically spherical units; (iii) aggregation of spheres into chain-like structures; (iv) growth of these structures; (v) secondary precipitation and phase transformation. The initially precipitated particles of the amorphous phase were observed to be round-shaped with 20-30 nm in size (although they can reach 120 nm in size) [145], but composed of smaller particles of 4 nm in size on average. It was also observed that an increase in the ripening time implied aggregation of spherical singlets and formation of needle-shaped calcium phosphates particles of about 20 nm in length [146].…”

Section: Crystallization Mechanisms Of Nanocrystalline Apatitesmentioning

confidence: 99%

Progress on the preparation of nanocrystalline apatites and surface characterization: Overview of fundamental and applied aspects

Gómez‐Morales¹,

Iafisco

Delgado-López³

et al. 2013

Progress in Crystal Growth and Characterization of Materials

237

268

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International audienceNanocrystalline calcium phosphate apatites constitute the main inorganic part of hard tissues, and a growing focus is devoted to prepare synthetic analogs, so-called "biomimetic", able to precisely mimic the morphological and physico-chemical features of biological apatite compounds. Both from fundamental and applied viewpoints, an accurate characterization of nanocrystalline apatites, including their peculiar surface features, and a deep knowledge of crystallization aspects are prerequisites to attempt understanding mineralization phenomena in vivo as well as for designing innovative bioactive materials that may then find applications in bone tissue engineering, either as self-supported scaffolds and fillers or in the form of coatings, but also in other domains such as drug delivery or else medical imaging. Also,interfacial phenomena are of prime importance for getting a better insight of biomineralization and for following the behavior of biomaterials in or close to their final conditions of use. In this view,both adsorption and ion exchange represent essential processes involving the surface of apatite nanocrystals, possibly doped with foreign elements or functionalized with organic molecules of interest. In this review paper, we will address these various points in details based on a large literature survey. We will also underline the fundamental physico-chemical and behavioral differences that exist between nanocrystalline apatites (whether of biological origin or their synthetic biomimetic analogs) and stoichiometric hydroxyapatite

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Survey of the Problem and Certain Definitions

Sergeev

2013

Nanochemistry

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Crystallization behavior of nanodisperse phases

Cited by 8 publications

References 9 publications

Nanosized hydroxyapatite and other calcium phosphates: Chemistry of formation and application as drug and gene delivery agents

Nanosized hydroxyapatite and other calcium phosphates: Chemistry of formation and application as drug and gene delivery agents

Progress on the preparation of nanocrystalline apatites and surface characterization: Overview of fundamental and applied aspects

Survey of the Problem and Certain Definitions

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