Temperature Driven Morphological Changes of Chemically Precipitated Hydroxyapatite Nanoparticles

Kumar, Rajendra; Prakash, K. H.; Cheang, P.; Khor, K.A.

doi:10.1021/la049304f

Cited by 218 publications

(193 citation statements)

References 32 publications

(58 reference statements)

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“…The solubility of HAp in acid environments is known to increase with temperature. [16] However, simulations indicate that the description of the interactions at the nanoparticle/bulk interface is not enough to promote the HOli dissolution, independently of the temperature. The influence of the acidic conditions was introduced in the mechanism by considering reactions (1) and (2) in the next MD step:…”

Section: Resultsmentioning

confidence: 99%

Dissolving Hydroxyolite: A DNA Molecule into Its Hydroxyapatite Mold

Bertrán

Revilla-López

Casanovas

et al. 2016

Chemistry A European J

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Abstract:In spite of the clinical importance of hydroxyapatite (HAp), the mechanism that controls its dissolution in acidic environments remains unclear. Knowledge of such process is highly desirable to provide better understanding of different pathologies, as for example osteoporosis, and of the HAp potential as vehicle for gene delivery to replace damaged DNA. In this work, the mechanism of dissolution in acid conditions of HAp nanoparticles encapsulating double-stranded DNA has been investigated at the atomistic level using computer simulations. For this purpose, four consecutive (multi-step) molecular dynamics simulations, involving different temperatures and proton transfer processes, have been carried out. Results are consistent with a polynuclear decalcification mechanism in which proton transfer processes, from the surface to the internal regions of the particle, play a crucial role. Besides, the DNA remains protected by the mineral mold and transferred proton from both temperature and chemicals. These results, which indicate that biomineralization imparts very effective protection to DNA, also have important implications in other biomedical fields, as for example in the design of artificial bones or in the fight against osteoporosis by promoting the fixation of Ca 2+ ions.

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Section: Resultsmentioning

confidence: 99%

Dissolving Hydroxyolite: A DNA Molecule into Its Hydroxyapatite Mold

Bertrán

Revilla-López

Casanovas

et al. 2016

Chemistry A European J

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“…In most of these conventional precipitation methods, the factors those precisely govern the precipitation, i.e., pH, temperature, CO 3 2-ion concentration, Ca/P mole ratio, etc., influence the morphological changes, resulting in the formation of HA nanocrystals with varying dimensions (Uota et al 2005). According to some previous reports (Ramachandra et al 1997;Kumar et al 2004;Prakash et al 2006a, b), the size of HA particle increases with increase in temperature, which has been attributed to the change in the concentration of Ca ?2 and CO 3 -2 ions pH, etc. For example, Prakash et al (2006a, b) found that the morphology of HA nanoparticles changed from needle shape to spherical, when the reaction of the sparingly soluble salts (Ca(OH) 2 and H 3 PO 4 ) was carried out in the temperature range 30-100°C.…”

Section: Introductionmentioning

confidence: 91%

Effect of temperature on morphology of triethanolamine-assisted synthesized hydroxyapatite nanoparticles

et al. 2012

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Hydroxyapatite (HA) nanoparticles have been synthesized using ortho-phosphoric acid as the source of PO 4 3-ions, and calcium chloride, suitably complexed with triethanolamine, as the calcium source. The effect of temperature on the morphology of the product has been investigated. The chemical compositions of the samples have been established through Fourier transform infrared spectroscopy. This study reveals that A-type and B-type carbonate substitution are present in HA samples and the concentration of carbonate ions decrease with rise in temperature. Morphological analyses by TEM studies suggest that the average lengths and widths of the needle-shaped particles size increases with temperature up to 50°C, while a morphological change of the particles from needle to spherical shape is observed on raising the temperature above 50°C. This change in morphology has been assigned to the apparent solubility of HA at these temperatures, which has been studied by the determination of thermochemical properties of the reaction system by endpoint conductivity and electrophoretic mobility measurements.

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“…According to some reports, isolated particles of HA and POSS are physically distinguished by their shapes: HA are generally described as having a needle-like (generally rods or with straight-taper ends) profile [55,56] while POSS particles may be described as having globular profiles [57]. While these descriptions are not based on a detailed analysis of the particle shapes, the precise form of these particles (at least for HA particles [25]) is expected to depend on the precipitation temperature, which ranges from ambient [58,59] to 40 • C [29,50,51,60].…”

Section: Study Findingsmentioning

confidence: 99%

A Comparative Analysis of the Reinforcing Efficiency of Silsesquioxane Nanoparticles versus Apatite Nanoparticles in Chitosan Biocomposite Fibres

Wang

Pasbakhsh²,

Silva

et al. 2017

J. Compos. Sci.

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A comparative analysis of the effects of polyhedral oligomeric silsesquioxane (POSS) and hydroxyapatite (HA) for reinforcing chitosan (CS) is given here. Wet-spun CS nanocomposite fibres, blended with HA or POSS nanoparticles, at varying concentrations ranging from 1 to 9% (w/w) were stretched until rupture to determine the mechanical properties related to the elasticity (yield strength and strain, stiffness, resilience energy) and fracture (fracture strength strain and toughness) of the composite. Two-factor analysis of variance of the data concluded that only the fracture-related properties were sensitive to interaction effects between the particle type and concentration. When particle type is considered, the stiffness and yield strength of CS/POSS fibres are higher than CS/HA fibres-the converse holds for yield strain, extensibility and fracture toughness. With regards to sensitivity to particle concentration, stiffness and yield strength reveal trending increase to a peak value (the optimal particle concentration associated with the critical aggregation) and trending decrease thereafter, with increasing particle concentration. Although fracture strength, strain at fracture and fracture toughness are also sensitive to particle concentration, no apparent trending increase/decrease is sustained over the particle concentration range investigated here. This simple study provides further understanding into the mechanics of particle-reinforced composites-the insights derived here concerning the optimized mechanical properties of chitosan composite fibre may be further developed to permit us to tune the mechanical properties to suit the biomedical engineering application.

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Temperature Driven Morphological Changes of Chemically Precipitated Hydroxyapatite Nanoparticles

Cited by 218 publications

References 32 publications

Dissolving Hydroxyolite: A DNA Molecule into Its Hydroxyapatite Mold

Dissolving Hydroxyolite: A DNA Molecule into Its Hydroxyapatite Mold

Effect of temperature on morphology of triethanolamine-assisted synthesized hydroxyapatite nanoparticles

A Comparative Analysis of the Reinforcing Efficiency of Silsesquioxane Nanoparticles versus Apatite Nanoparticles in Chitosan Biocomposite Fibres

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