Formation of Hydroxyapatite Whiskers by Hydrothermal Homogeneous Precipitation Using Acetamide

Zhang, Hongquan; Darvell, B.W.

doi:10.1111/j.1551-2916.2010.04338.x

Cited by 23 publications

(12 citation statements)

References 38 publications

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“…Phase and FTIR analyses of the obtained products completely oppose the literature's [44] where produced whiskers were found to be biphasic mixtures of apatitic calcium-phosphate and octacalcium phosphate (Ca 8 H 2 (PO 4 ) 6 · 5 H 2 O). In our tests XRD patterns did not show the characteristic peak of OCP at around 2θ = 5°and no characteristic FTIR absorption bands of OCP at 865 and 910 cm -1 were observed [56,57].…”

Section: Resultscontrasting

confidence: 66%

Influence of low-temperature reaction time on morphology and phase composition of short calcium phosphate whiskers

Biernat

Jaegermann

Tymowicz-Grzyb

et al. 2019

PAC

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The present work shows the results of the synthesis of multiphasic calcium phosphate whiskers from a mixture of biphasic calcium phosphate (β-tricalcium phosphate (β-TCP) and calcium pyrophosphate (CPP)) in the hydrogen peroxide solution-mediated process carried out in different time ranges. The process was performed at considerably lower temperature than typical hydrothermal methods used for obtaining of whiskers. Test results show that using the above-mentioned procedure triphasic calcium phosphate consisting of hydroxyapatite (HA), (β-TCP) and CPP can be obtained, where the whiskers are formed mainly from hydroxyapatite. It was found that morphology, phase composition and specific surface area of the reaction product can be controlled by changing the reaction time. The obtained triphasic HA/β-TCP/CPP short whiskers may be considered as a promising biocompatible and resorbable reinforcement in composites for bone tissue engineering with a faster resorption rate than that of HA.

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Section: Resultscontrasting

confidence: 66%

Influence of low-temperature reaction time on morphology and phase composition of short calcium phosphate whiskers

Biernat

Jaegermann

Tymowicz-Grzyb

et al. 2019

PAC

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“…The two latter methods are based on the hydrolysis of an organic additive which is commonly an amide used to control the solution pH and to modify the crystal growth. The use of several amides such as carbonyl diamide (urea) [1,13,14], acetamide [14,15], formamide [13], and propanamide [16] as additive has been reported. It is believed that the use of those amides leading to a rapid rise in solution pH should be avoided due to the quick growth of HA, which promotes the formation of the aggregates [13].…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of single phase, biphasic and triphasic calcium phosphate whisker-like fibers by homogenous precipitation using urea

Mohammadi

Mesgar

Rasouli-Disfani

2016

Ceramics International

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Whisker−like calcium phosphate fibers were prepared by a homogenous precipitation method under refluxing conditions in solutions with a Ca/P molar ratio of 1.67 at 90°C and pH 3.0 using urea as additive. The precipitates were characterized by XRD, FTIR, SEM, and FE−SEM. The ICP spectroscopy and elemental analyzer were used to determine Ca/P ratio and carbonate content of products, respectively. The results indicate that the morphology and structural characteristics of the precipitates depend on the urea concentration and reaction time. Whisker−like biphasic monetite/hydroxyapatite (HA) fibers with a mean length of 60 µm and a mean width of 1.0 µm were obtained with the use of a low concentration of urea. Calcination of the biphasic calcium phosphate at 800 °C led to the formation of a triphasic mixture of HA/whitlockite (β−TCP)/calcium pyrophosphate (CPP) with a whisker−like morphology. The use of a higher concentration of urea was caused to form a mixed morphology of spherulites/whisker−like fibers consisting of octacalcium phosphate (OCP) and HA phases. When the reaction time was increased to 10 days, both the above biphasic calcium phosphates transformed to a single phase HA which its morphology and growth pattern were similar to those of a whisker, according to FE−SEM images. The HA whiskers produced by a lower amount of urea had a lower carbonate content compared to those obtained using a higher urea concentration.

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“…Medical untethered micromotors are engineered small devices which can move in biological environments by chemical reactions, external physical fields or by motile cells and/or microorganisms . They come in different shapes, one of the most prominent ones being particle micromotors, which have been used to demonstrate different motion mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Real‐Time IR Tracking of Single Reflective Micromotors through Scattering Tissues

Aziz

Medina‐Sánchez

Koukourakis

et al. 2019

Adv Funct Materials

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Medical micromotors have the potential to lead to a paradigm shift in future biomedicine, as they may perform active drug delivery, microsurgery, tissue engineering, or assisted fertilization in a minimally invasive manner. However, the translation to clinical treatment is challenging, as many applications of single or few micromotors require real-time tracking and control at high spatiotemporal resolution in deep tissue. Although optical techniques are a popular choice for this task, absorption and strong light scattering lead to a pronounced decrease of the signal-to-noise ratio with increasing penetration depth. Here, a highly reflective micromotor is introduced which reflects more than tenfold the light intensity of simple gold particles and can be precisely navigated by external magnetic fields. A customized optical IR imaging setup and an image correlation technique are implemented to track single micromotors in real-time and label-free underneath phantom and ex vivo mouse skull tissues. As a potential application, the micromotors speed is recorded when moving through different viscous fluids to determine the viscosity of diverse physiological fluids toward remote cardiovascular disease diagnosis. Moreover, the micromotors are loaded with a model drug to demonstrate their cargotransport capability. The proposed reflective micromotor is suitable as theranostic tool for sub-skin or organ-on-a-chip applications.

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Formation of Hydroxyapatite Whiskers by Hydrothermal Homogeneous Precipitation Using Acetamide

Cited by 23 publications

References 38 publications

Influence of low-temperature reaction time on morphology and phase composition of short calcium phosphate whiskers

Influence of low-temperature reaction time on morphology and phase composition of short calcium phosphate whiskers

Preparation and characterization of single phase, biphasic and triphasic calcium phosphate whisker-like fibers by homogenous precipitation using urea

Real‐Time IR Tracking of Single Reflective Micromotors through Scattering Tissues

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