Dataset Information

Calcium-deficient Hydroxyapatite as a Potential Sorbent for Strontium.

ABSTRACT: A calcium (Ca)-deficient hydroxyapatite was investigated for its potential to remove Sr2+ from environmentally relevant water. We conducted sorption tests on solutions containing magnesium ion (Mg2+) and calcium ion (Ca2+) as competing cations at a strontium ion (Sr2+) concentration of 0.05?mmol/L. The Ca-deficient hydroxyapatite maintained a high Sr2+ sorption ratio of above 80% in the presence of Mg2+ and Ca2+ at the concentrations between 0.1 and 1.0?mmol/L, whereas the stoichiometric hydroxyapatite showed a lower ratio even in the presence of small amounts of Mg2+ and Ca2+ (72% for Mg2+ and 51% for Ca2+ at 0.1?mmol/L). For solutions with various Sr2+ concentrations between 0.01 and 10?mmol/L, Ca-deficient hydroxyapatite exhibited a higher Sr2+ sorption ratio than stoichiometric hydroxyapatite. The bonding states of Sr2+ on the Ca-deficient hydroxyapatite were evaluated by extended X-ray absorption fine structure measurements. The results indicated that there are specific sorption sites in Ca-deficient hydroxyapatite where Sr2+ is stably and preferentially immobilized.

SUBMITTER: Sekine Y

PROVIDER: S-EPMC5437100 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature

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Calcium-deficient Hydroxyapatite as a Potential Sorbent for Strontium.

Sekine Yurina Y Motokawa Ryuhei R Kozai Naofumi N Ohnuki Toshihiko T Matsumura Daiju D Tsuji Takuya T Kawasaki Riku R Akiyoshi Kazunari K

Scientific reports 20170518 1

A calcium (Ca)-deficient hydroxyapatite was investigated for its potential to remove Sr2+ from environmentally relevant water. We conducted sorption tests on solutions containing magnesium ion (Mg2+) and calcium ion (Ca2+) as competing cations at a strontium ion (Sr2+) concentration of 0.05 mmol/L. The Ca-deficient hydroxyapatite maintained a high Sr2+ sorption ratio of above 80% in the presence of Mg2+ and Ca2+ at the ...[more]

PMID: 28522874

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Project description:Osseointegration of implants depends on several intertwined factors: osteogenesis, angiogenesis, and immunomodulation. Lately, novel reinforcements allowing faster bonding with osseous tissue have been explored intensively. In this study, we hypothesized the use of boron as a major multifunctional ion to confer versatility to calcium-deficient hydroxyapatite (cHA) synthesized by a wet precipitation/microwave reflux method. By synthesis of boron-doped calcium-deficient hydroxyapatite (BcHA), we expected to obtain an osteoimmunomodulatory and regenerative nanoreinforcement. BcHA was found to possess a pure HA phase, a greater surface area (66.41 m2/g, p = 0.028), and cumulative concentrations of Ca (207.87 ± 6.90 mg/mL, p < 0.001) and B (112.70 ± 11.79 mg/mL, p < 0.001) released in comparison to cHA. Osteogenic potential of BcHA was analyzed using human fetal osteoblasts. BcHA resulted in a drastic increase in the ALP activity (1.11 ± 0.11 mmol/gDNA·min, p < 0.001), biomineralization rate, and osteogenic gene expressions compared to cHA. BcHA angiogenic potential was investigated using human umbilical cord vein endothelial cells. Significantly, the highest VEGF-A release (1111.14 ± 87.82 in 4 h, p = 0.009) and angiogenic gene expressions were obtained for BcHA-treated samples. These samples were also observed to induce a more prominent and highly branched tube network. Finally, inflammatory and inflammasome responses toward BcHA were elucidated using human monocyte-derived macrophages differentiated from THP-1s. BcHA exhibited lower CAS-1 release (50.18 ± 5.52 μg/gDNA μg/gDNA) and higher IL-10 release (126.97 ± 15.05 μg/gDNA) than cHA. In addition, BcHA treatment led to increased expression of regenerative genes such as VEGF-A, RANKL, and BMP-2. In vitro results demonstrated that BcHA has tremendous osteogenic, angiogenic, and immunomodulatory potential to be employed as a "versatile-in-all-trades" modality in various bone tissue engineering applications.

Project description:PurposeThis study developed light cured dental composites with added monocalcium phosphate monohydrate (MCPM), tristrontium phosphate (TSrP) and antimicrobial polylysine (PLS). The aim was to produce composites that have enhanced water sorption induced expansion, can promote apatite precipitation and release polylysine.Materials and methodsExperimental composite formulations consisted of light activated dimethacrylate monomers combined with 80 wt% powder. The powder phase contained a dental glass with and without PLS (2.5 wt%) and/or reactive phosphate fillers (15 wt% TSrP and 10 wt% MCPM). The commercial composite, Z250, was used as a control. Monomer conversion and calculated polymerization shrinkage were assessed using FTIR. Subsequent mass or volume changes in water versus simulated body fluid (SBF) were quantified using gravimetric studies. These were used, along with Raman and SEM, to assess apatite precipitation on the composite surface. PLS release was determined using UV spectroscopy. Furthermore, biaxial flexural strengths after 24 hours of SBF immersion were obtained.ResultsMonomer conversion of the composites decreased upon the addition of phosphate fillers (from 76 to 64%) but was always higher than that of Z250 (54%). Phosphate addition increased water sorption induced expansion from 2 to 4% helping to balance the calculated polymerization shrinkage of ~ 3.4%. Phosphate addition promoted apatite precipitation from SBF. Polylysine increased the apatite layer thickness from ~ 10 to 20 μm after 4 weeks. The novel composites showed a burst release of PLS (3.7%) followed by diffusion-controlled release irrespective of phosphate addition. PLS and phosphates decreased strength from 154 MPa on average by 17% and 18%, respectively. All formulations, however, had greater strength than the ISO 4049 requirement of > 80 MPa.ConclusionThe addition of MCPM with TSrP promoted hygroscopic expansion, and apatite formation. These properties are expected to help compensate polymerization shrinkage and help remineralize demineralized dentin. Polylysine can be released from the composites at early time. This may kill residual bacteria.

Dataset Information

Calcium-deficient Hydroxyapatite as a Potential Sorbent for Strontium.

Publications

Calcium-deficient Hydroxyapatite as a Potential Sorbent for Strontium.

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