Hydroxyapatite In article number 2204938, Tae Yong Kim, Jae‐Soon Choi, Jeong Woo Han, and co‐workers present a insightful summary and research perspective on the design of hydroxyapatite (HAP) ...catalysts as a green catalyst. Detailed mechanisms and the effects of structural modifications on catalytic performance are investigated, offering valuable insights into strategies for achieving highly selective HAP catalysts.
Biomimicking ceramics have been developed to induce efficient recovery of damaged hard tissues. Among them, calcium phosphate-based bioceramics have been the most widely used because of their similar ...composition with human hard tissue and excellent biocompatibilities. However, the incomplete understanding of entire inorganic phases in natural bone has limited the recreation of complete bone compositions. In this work, broad biomedical evaluation of whitlockite (WH: Ca18Mg2(HPO4)2(PO4)12), which is the secondary inorganic phase in bone, is conducted to better understand human hard tissue and to seek potential application as a biomaterial. Based on the recently developed gram-scale method for synthesizing WH nanoparticles, the properties of WH as a material for cellular scaffolding and bone implants are assessed and compared to those of hydroxyapatite (HAP: Ca10(PO4)6(OH)2) and beta-tricalcium phosphate (beta-TCP: beta-Ca3(PO4)2). WH-reinforced composite scaffolds facilitate bone-specific differentiation compared to HAP-reinforced composite scaffolds. Additionally, WH implants induce similar or better bone regeneration in calvarial defects in a rat model compared to HAP and beta-TCP implants, with intermediate resorbability. New findings of the properties of WH that distinguish it from HAP and beta-TCP are significant in understanding human hard tissue, mimicking bone tissue at the nanoscale and designing functional bioceramics.
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•Synthetic methods for obtaining hydroxyapatite are reviewed.•The structure-reactivity studies of hydroxyapatite as related to catalysis performances are discussed.•The catalytic ...applications of hydroxyapatite are introduced and discussed.
The synthesis of hydroxyapatite (HAP) and its applications in heterogeneous catalysis are abridged in view of its demonstrated prowess and utility in chemical, material and industrial industry. This overview documents the strengths and weaknesses of the synthetic routes that have been applied to the synthesis of hydroxyapatite with description of salient structural properties of hydroxyapatite responsible for its reactivity. The significant applications of hydroxyapatite both, as an inorganic support and as a catalyst are described with an emphasis on its performance, stability and reusability. Several newer findings as well as the current challenges pertaining to the use of hydoxyapetite are summarized.
Retraction of 'Synthesis of triazolidine-3-one derivatives through the nanocellulose/hydroxyapatite-catalyzed reaction of aldehydes and semicarbazide' by Vashen Moodley
et al.
,
New J. Chem.
, 2017,
...41
, 6455-6463, DOI:
10.1039/c7nj00855d
.
To improve the regenerative performance of nano-hydroxyapatite/coralline (nHA/coral) block grafting in a canine mandibular critical-size defect model, nHA/coral blocks were coated with recombinant ...human vascular endothelial growth factor(165) (rhVEGF) via physical adsorption (3 μg rhVEGF165 per nHA/coral block). After the nHA/coral blocks and VEGF/nHA/coral blocks were randomly implanted into the mandibular box-shaped defects in a split-mouth design, the healing process was evaluated by histological observation and histomorphometric and immunohistological analyses. The histological evaluations revealed the ingrowth of newly formed blood vessels and bone at the periphery and cores of the blocks in both groups at both 3 and 8 weeks postsurgery, respectively. In the histomorphometric analysis, the VEGF/nHA/coral group exhibited a larger quantity of new bone formation at 3 and 8 weeks postsurgery. The percentages of newly formed bone within the entire blocks in the VEGF/nHA/coral group were 27.3% ± 8.1% and 39.3% ± 12.8% at 3 weeks and 8 weeks, respectively, and these values were slightly greater than those of the nHA/coral group (21.7% ± 3.0% and 32.6% ± 10.3%, respectively), but the differences were not significant (P>0.05). The immunohistological evaluations revealed that the neovascular density in the VEGF/nHA/coral group (146 ± 32.9 vessel/mm(2)) was much greater than that in the nHA/coral group (105 ± 51.8 vessel/mm(2)) at the 3-week time point (P<0.05), but no significant difference was observed at the 8-week time point (341 ± 86.1 and 269 ± 50.7 vessel/mm(2), respectively, P>0.05). The present study indicated that nHA/coral blocks might be optimal scaffolds for block grafting in critical-size mandibular defects and that additional VEGF coating via physical adsorption can promote angiogenesis in the early stage of bone healing, which suggests that prevascularized nHA/coral blocks have significant potential as a bioactive material for bone regeneration in large-scale alveolar defects.
About 80% of wastewater is discarded into the environment without any treatment. In this research work, the metal hydroxyapatite nanoparticles had been synthesized by a wet chemical approach and ...applied in water treatment applications by using them as adsorbents for the removal of Red 3R dye from an aqueous solution. The obtained products had been characterized by FTIR spectroscopic technique to confirm the synthesis of respective products by ensuring the presence of phosphate and hydroxyl functional groups. Batch experiments were performed and all effective parameters were optimized and their optimized values were 21 mg/g achieved at pH 7.0, adsorbent dose 0.05 g, initial dye concentration 75 mg/L, and contact time 75 min using metal hydroxyapatite nanoparticles. Moreover, the effect of surfactants and electrolytes was also studied. The Red 3R dye adsorption process was explained by the Langmuir isotherm this type of behavior showed the formation of a monolayer of dye molecules on the adsorbent surface and pseudo-second-order kinetic model. The thermodynamic parameters indicated that Red 3R dye adsorption was exothermic and spontaneous. Given the promising adsorption efficiency of metal hydroxyapatite nanoparticles, they might be used as an alternative class of adsorbents for the adsorption of dyes from industrial effluents.
Graphical Abstract
The current study focuses on the synthesizing of novel hybrid nanosystems of bio‐hydroxyapatite (BioHAp)/synthetic‐hydroxyapatite (HAp‐Syn). Bio‐HAp was defatted, deproteinized, and then sonicated to ...obtain nanoparticles (nBioHAp). Hybrid nanosystems (HNS) were synthesized by wet chemical precipitation using nBioHAp as nucleation sites and applying four different precipitation times of 45, 90, 135, and 180 min. X‐ray diffraction (XRD) showed that the patterns of the nBioHAp and HAp‐Syn samples have broadened diffraction peaks due to simultaneous elastic and inelastic scattering. Their crystallite size is about 25 nm, while the hybrid nanosystems have a size between 35 and 40 nm. Fourier‐transform infrared spectroscopy (FT‐IR) revealed the main groups associated with hydroxyapatite (PO32−, OH−, and CO32−), and the nanometer character of the crystals was demonstrated by studying the full width at half maximum (FWHM) of the spectra. Scanning electron microscopy (SEM) revealed the differences between the morphologies of nBioHAp and HAp‐Syn. The shape of HNS resembled that of biogenic HAp, which was confirmed by transmission electron microscopy (TEM). Inductively coupled plasma spectroscopy (ICP‐OES) and energy dispersive X‐ray spectroscopy (EDS) were used to confirm the elemental composition of Mg, Na, K, and Zn as minority ions.
Novel hydroxyapatite hybrid nanosystems (HAp‐HNS) combining biogenic and synthetic HAp are important for their versatile applications and tailored properties, which optimize them for specific applications. They are biocompatible for bone regeneration due to substitutional ions. In addition, these nanosystems are adsorbent and can serve as effective carriers for drug delivery and removal of contaminants from water and soil.
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