Calcium hydroxyapatite (Ca10(PO4)6(OH)2) has been synthesized in short duration by rapid solution combustion by employing different fuels. Calcium nitrate was taken as source of calcium and diammonium hydrogen phosphate served as the source of phosphate ions. Citric acid, tartaric acid, sucrose, glycine and urea were used as the fuels and nitrate ions and nitric acid were used as oxidizers. The influence of fuels on the morphology of the phase formed was studied. Results of the studies by powder X-ray diffraction and Fourier-transform infrared spectroscopy showed the formation of hydroxyapatite as a major phase for all the fuels. The thermal analysis of the decomposed precursor showed variation in heat content for different fuels. Scanning electron microscopy showed different morphologies of the products obtained by different fuels. Chemical analyses to determine the Ca:P atomic ratio in synthesized ceramics showed that the ratio was 1:1.66. © 2010 The Chinese Society for Metals.

Sasikumar S

Department of Chemistry

School of Advanced Sciences

Vellore Campus

Vijayaraghavan R

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

&nbsp;

&nbsp;

VIT University

Synthesis and Characterization of Bioceramic Calcium Phosphates by Rapid Combustion Synthesis

Journal of Materials Science & Technology

Bioceramics used in hard tissue engineering applications should primarily meet the criteria of mechanical strength and apatite mineralisation of natural bone. In such a scenario, designing of bioceramic composites is inevitable as calcium silicates possess good apatite deposition ability and magnesium silicates show excellent mechanical stability. The present study investigates the influence of calcium (Ca) and magnesium (Mg) ions of the bioceramics on bioactivity and mechanical strength. Binary silicates such as wollastonite (CaSiO3), enstatite (MgSiO3) and forsterite (Mg2SiO4) were prepared by sol-gel combustion technique. Functional group identification and phase formation of the silicate materials were analysed by FT-IR and X-ray diffraction studies respectively. Furthermore, apatite mineralisation ability and mechanical strength of wollastonite were evaluated. Influence of wollastonite on the bioactivity of both enstatite and forsterite was also investigated. The obtained results conferred that the wollastonite possesses good apatite formation ability, moderate resorbability and low mechanical strength. The composites of wollastonite show improvement in the enstatite with respect to bioactivity and in forsterite with respect to superior mechanical properties. © 2019 Wiley-VCH Verlag GmbH &amp; Co. KGaA, Weinheim

ChemistrySelect

Synthesis, Bioactivity and Mechanical Stability of Mg/Ca Silicate Biocomposites Developed for Tissue Engineering Applications

This work reports on the preparation and characterization of mesoporous nano diopside (CaMgSi2O6) using a simple and cost-effective sol-gel combustion route. Stoichiometric oxidant/fuel ratio was adopted for the combustion reaction. Eggshell was used as a calcium source, glycine (fuel) as reductant, magnesium nitrate and nitric acid as oxidant were used in the preparation. The thermal behavior of the precursor was studied by thermo-gravimetric analysis (TGA) and heating microscopy. The temperature required for the transformation of the precursor into pure diopside was optimized at 1100 °C. Rietveld refinement method was utilized to confirm the phase purity of diopside. The resultant powder contains 36 nm particle with a specific surface area of 51 m2/g. The appearance of Ca, Mg, Si, and O peaks in EDX pattern confirmed the existence of essential elements. The rapid consumption of calcium and phosphorus ions from the simulated body fluid during dissolution indicated their involvement in apatite deposition on the surface of the nano diopside. FT-IR spectra showed that the Si[sbnd]O and Si[sbnd]O[sbnd]Si groups were replaced by phosphate bands due to hydroxyapatite deposition. The mechanical stability of the diopside after bioactivity studies was found to be superior to the cancellous bone. The release of alkaline earth ions (Ca2+ and Mg2+) from the diopside sample into the bacterial culture medium increases the pH (7.4), which inhibits the bacterial growth. The surface properties, concentration, and type of bacteria are the other factors responsible for the antibacterial activity of the nano diopside. © 2019 The Society of Powder Technology Japan

Advanced Powder Technology

Biomineralization, antibacterial activity and mechanical properties of biowaste derived diopside nanopowders

AbstractSodium calcium silicate (Na2CaSiO4) is a bioactive silicate with Na2O, CaO and SiO2 as its basic components, which is similar to that of the composition of bioactive glasses. In the present study, pure sodium calcium silicate was synthesized by rapid combustion technique, and the synthesized sample was characterized by powder X-ray diffraction to check the phase purity. The scaffolds were prepared by varying the ratio of sodium calcium silicate and polyvinyl alcohol, and the apatite-formation ability of the scaffolds was examined by soaking them in a simulated body fluid. The results revealed the formation of hydroxyapatite on the surface of the scaffold after 5 days, which is found to be rapid when compared with the bioactivity of the calcium silicates and calcium magnesium silicates. The scaffolds were also loaded with ciprofloxacin as a model drug and analyzed for its drug release profile using UV spectrophotometer. The release profile did not vary with the change in bioceramic-to-biopolymer ratio, and 60% of the drug was released in 10 days, which is within the appreciable range for a targeted drug delivery system. Moreover, the experimental and simulated values of the release kinetics were compared by applying the existing mathematical model.

Fulltext

Science and Engineering of Composite Materials

Synthesis, characterization and formulation of sodium calcium silicate bioceramic for drug delivery applications

Diopside was synthesized from biowaste (Eggshell) by sol-gel combustion method at low calcination temperature and the influence of two different fuels (urea, l-alanine) on the phase formation temperature, physical and biological properties of the resultant diopside was studied. The synthesized materials were characterized by heating microscopy, FTIR, XRD, BET, SEM and EDAX techniques. BET analysis reveals particles were of submicron size with porosity in the nanometer range. Bone-like apatite deposition ability of diopside scaffolds was examined under static and circulation mode of SBF (Simulated Body Fluid). It was noticed that diopside has the capability to deposit HAP (hydroxyapatite) within the early stages of immersion. ICP-OES analysis indicates release of Ca, Mg, Si ions and removal of P ions from the SBF, but in different quantities from diopside scaffolds. Cytocompatability studies on human bone marrow stromal cells (hBMSCs) revealed good cellular attachment on the surface of diopside scaffolds and formation of extracellular matrix (ECM). This study suggests that the usage of eggshell biowaste as calcium source provides an effective substitute for synthetic starting materials to fabricate bioproducts for biomedical applications. © 2016 Elsevier B.V. All rights reserved.

Materials Science and Engineering: C

In-vitro bioactivity, biocompatibility and dissolution studies of diopside prepared from biowaste by using sol–gel combustion method

The present study focused on the synthesis of calcium magnesium silicate (akermanite, Ca 2 MgSi 2 O 7 ) using eggshell biowaste (as calcium source), magnesium nitrate and tetraethyl orthosilicate (TEOS) as starting materials. Sol-gel combustion method was adopted to obtain calcium magnesium silicate. Citric acid was used as a fuel (reducing agent) and nitrate ions present in the metal nitrates acts as an oxidizing agent during combustion process. The characterization of synthesized calcium magnesium silicate was carried out by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) techniques. Calcium magnesium silicate crystallite size was observed in nano regime which can effectively mimic natural bone apatite composition. In-vitro bioactivity was investigated by immersing calcium magnesium silicate pellet in simulated body fluid (SBF) for three weeks. Results show effective deposition of crystallized hydroxyapatite (HAP) layer on its surface and predicting its possibilities for applications in hard tissue regeneration. © 2015 The Ceramic Society of Japan and the Korean Ceramic Society.

Journal of Asian Ceramic Societies

Bioactivity studies of calcium magnesium silicate prepared from eggshell waste by sol–gel combustion synthesis

Synthetic calcium hydroxyapatite (HAP, Ca10 (PO 4)6 (OH)2) is a well-known bioceramic material used in orthopedic and dental applications because of its excellent biocompatibility and bone-bonding ability due to its structural and compositional similarity to human bone. Here we report, for the first time, the synthesis of HAP by combustion employing tartaric acid as a fuel. Calcium nitrate is used as the source of calcium and diammonium hydrogen phosphate serves as the source of phosphate ions. Reaction processing parameters such as the pH, fuel-oxidant ratio and autoignition temperature are controlled and monitored. The products were characterized by powder x-ray diffraction, which revealed the formation of a hexagonal hydroxyapatite phase. Fourier transform infrared spectroscopy (FT-IR) spectra showed that the substitution of a carbonate ion occurs at the phosphate site. The morphology of the particles was imaged by scanning electron microscopy, which also revealed that the particles are of submicron size. Thermal analysis showed that the phase formation takes place at the time of combustion. Surface area and porosity analysis showed that the surface area is high and that the pores are of nanometer size. The mean grain size of the HAP powder, determined by the Debye-Scherrer formula, is in the range 20-30 nm. Chemical analyses to determine the Ca : P atomic ratio in synthesized ceramics were performed, and it was found to be 1 : 1.66. © 2008 National Institute for Materials Science.

Science and Technology of Advanced Materials

Effect of metal-ion-to-fuel ratio on the phase formation of bioceramic phosphates synthesized by self-propagating combustion

Calcium phosphate based bioceramics have been synthesized by a modified combustion synthetic route using both citric acid and succinic acid separately and in mixture as fuels and nitrate and nitric acid as oxidants. Calcium nitrate and diammonium hydrogen phosphate were used as calcium and phosphate sources. The effects of citric acid to succinic acid ratio on the phase formation have been investigated. The precursors and the calcined products have been characterized by powder X-ray diffraction, Fourier-transform infrared spectroscopy and scanning electron microscopy. Succinic acid has been used as a fuel for the first time to synthesize hydroxyapatite. Hydroxyapatite phase is formed when either citric acid or succinic acid is used as a fuel and β-tricalcium phosphate phase is formed when a mixture of citric acid and succinic acid is used as a fuel as revealed by powder X-ray diffraction. The average crystallite size of the synthesized powder determined by Debye-Scherrer formula is found to be in the range of 55-65 nm. Surface morphology of the samples was imaged using scanning electron microscope. Chemical analysis shows that the Ca:P ratio in synthesized ceramics is 1.67. Results are discussed in terms of the phases present in the precursors formed during single and mixed fuel approaches and also its carbonate content present in hydroxyapatite products. © 2007 Elsevier Ltd and Techna Group S.r.l.

Journal	Data powered by TypesetJournal of Materials Science & Technology
Publisher	Data powered by TypesetElsevier BV
ISSN	1005-0302
Open Access	No