Novel multifunctional of magnesium ions (Mgþþ) incorporated calcium phosphate nanostructures (original) (raw)
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MULTIFUNCTIONAL BEHAVIOUR OF MAGNESIUM/CALCIUM PHOSPHATE
Pure and magnesium/nano hydroxyapatite (HAp) prepared by microwave route. The sample was analyzed by X-Ray Diffraction (XRD), photoluminescence (PL) and bioactivity. The XRD analysis was revealed that pure phase of HAp. As the concentration of magnesium ion increases, the average crystallite was reduced. The PL and in vitro bioactivity of the doped sample were enhanced. Hence, magnesium based calcium phosphate could be a suitable candidate for multifunctional applications.
Development of Magnesium-Doped Biphasic Calcium Phosphatethrough Sol-Gel Method
IFMBE Proceedings, 2008
Calcium phosphate is an interesting material for bone implant applications, as it shows biocompatibility and bioactivity to tissue bone. Among calcium phosphate-based materials, biphasic calcium phosphate (BCP), a mixture of non-resorbable hydroxyapatite (HA) and resorbable tricalcium phosphate (TCP), has shown to possess unique characteristics appropriate for bone replacement. Doping of magnesium ions into BCP will bring biological improvement. Magnesium ion was found to cause the acceleration of nucleation kinetics of bone minerals. Magnesium depletion adversely affects all stages of skeletal metabolism, leading to decrease in osteoblastic activities and bone fragility. Therefore, the incorporation of magnesium ions into the calcium phosphate structure is of great interest for the development of artificial bone implants. Here we present magnesium-doped biphasic calcium phosphate (Mg-BCP) using chemical doping process through a solgel method. Mg-BCP was produced using calcium nitrate tetrahydrate and di-ammonium hydrogen phosphate as the precursors for calcium and phosphorus, respectively. Magnesium nitrate was used as the source of the dopant. An ammoniacal solution of the monomers was heated until a white gel was obtained. The obtained gel was then dried and subsequently subjected to calcinations. The change in physicochemical properties has been evaluated by using XRD, FTIR, TG/DTA, and FESEM. Individual particles are of less than 100 nm in size, spherical shapes and tightly agglomerated. XRD measurement shown that the powder is Mg-doped BCP with 100% purity, and crystallinity increased with increased of Mg content. FTIR spectroscopy measurement also showed that the increment of crystallinity is directly proportional to the amount of dopant leading to the conclusion that magnesium acts as a sintering additive. This result is in good agreement with the analysis of FESEM where the particles of the Mgdoped BCP are larger as the amount of dopant increased as a result of more progressive fusion of particles.
Materials Science and Engineering: C, 2009
Tricalcium phosphate (TCP, Ca 3 (PO 4 ) 2 ) in its pure form cannot be synthesized under physiological conditions in normal aqueous solutions due to phase instability, resulting in its transformation to hydroxyapatite (HA, Ca 10 (PO 4 ) 6 (OH) 2 ) in the presence of water. However, substituting magnesium in lieu of calcium is known to stabilize TCP, preventing its conversion to hydroxyapatite. There are several methods known for synthesizing magnesium substituted tricalcium phosphate (TCMP). In the present study, a novel in-situ method has been developed to synthesize β-TCMP using magnesium substituted brushite as a precursor. Substitution of 50% of calcium by magnesium results in the formation of semi-spherical nanocrystalline particles (∼ 100 nm) of brushite. Boiling the nanocrystalline brushite powder in aqueous condition for only 30 min results in the generation of rosette shaped nanocrystals (∼ 80 nm) of β-TCMP that emerge from the original brushite spheres. The β-TCMP particles exhibit a specific surface area of ∼ 200 m 2 /g. Details about the synthesis procedure and the possible mechanisms involved in the formation of β-TCMP from Mg-substituted brushite is further discussed.
Incorporation of metal as sintering additive is a simple way to improve physical and mechanical properties of biphasic calcium phosphate (BCP) materials as well as its performance in biomedical applications. In this work, magnesium (Mg) was incorporated into the BCP as sintering additive to improve the properties of BCP. The aim of this work was to study the effect of Mg doping to the BCP on its phase behavior. Mg-doped BCP powders have been synthesized via sol-gel method. The as prepared powders at different Mg concentration were calcined at different temperatures ranged from 500°C to 900°C. FT-IR technique was used to study the phase behavior and thermal stability of as prepared powders. FT-IR study revealed that the intensity of the OH band of HA phase was increased with the powder crystallinity and calcination temperature. FT-IR analysis confirmed the formation of biphasic mixtures of HA and Mg stabilized ȕ-TCP in the synthesized powders when calcined at high temperatures as bands of HPO 4 -2 and P 2 O 7 -4 decreased. Moreover, FT-IR study also showed that the intensity of peak resolution of OH and PO 4 bands are viewed less intensity with the increased in Mg percent concentration. FT-IR also revealed the presence of stable phase of P 2 O 5 band at 400-450 cm -1 which promotes the crystal growth Mg-doped BCP powder.
Materials
Calcium phosphate (CaP) with several chemical compositions and morphologies was prepared by precipitation using aqueous solutions of L-Glutamic acid (H2G) and calcium hydroxide, both mixed together with an aqueous solution (0.15 M) of phosphoric acid. Plate-shaped dicalcium phosphate dihydrate (brushite) particles were obtained and identified at a lower concentration of the solution of the reactants. The Ca/P ratio deduced by EDS was ~1, as expected. The nanoscale dimension of carbonate apatite and amorphous calcium phosphate, with variable Ca/P ratios, were revealed by X-ray diffraction (XRD) and scanning electron microscopy and energy dispersive X-ray spectroscopy analysis (SEM-EDS). They were characterized in medium and high concentrations of calcium hydroxide (0.15 M and 0.20 M). The equilibria involved in all the reactions in aqueous solution were determined. The thermodynamic calculations showed a decrease in the amount of chelate complexes with an increase in pH, being the op...
Nanostructured calcium phosphates for biomedical applications: novel synthesis and characterization
Acta Biomaterialia, 2005
Materials play a key role in several biomedical applications, and it is imperative that both the materials and biological aspects are clearly understood for attaining a successful biological outcome. This paper illustrates our approach to implement calcium phosphates as gene delivery agents. Calcium phosphates (CaP) belong to the family of biocompatible apatites and there are several CaP phases, the most ubiquitous being hydroxyapatite (HAp, Ca 10 (PO 4 ) 6 (OH) 2 . Other CaP structures include brushite (B, CaHPO 4 AE 2H 2 O) and tricalcium phosphate (TCP, Ca 3 (PO 4 ) 2 ). Several low and high temperature approaches have been reported for synthesizing HAp and brushite, while TCP is primarily synthesized using high temperature methods. Novel low temperature chemical methods have been developed by us to synthesize nanostructured HAp, brushite and TCP phases. The new low temperature approach results in the formation of stoichiometric and nanosized HAp under physiological conditions. Moreover, the synthesis methods were designed to be biocompatible with biological systems such as cells, DNA and proteins so that the CaP structures can be studied for gene delivery. The use of HAp type CaP phases for gene delivery is well known but to our knowledge, other forms of CaP have not been studied for gene delivery due to the lack of a biocompatible synthesis method. In addition to the biocompatible synthesis of CaP structures, we have also performed ion substitution that would provide us the appropriate tools to study the DNA-to-particle interactions and assess how these ionic substitutions would affect the level of DNA uptake by the cell and then its release to the cell nucleus.
Elaboration biphasic calcium phosphate nanostructured powders
Boletín de la Sociedad Española de Cerámica y Vidrio, 2015
Nanostructured calcium phosphate and biphasic calcium phosphates have been studied and stand out as biomaterials for bone regeneration. This is due to the fact that thesebiomaterials present bioactivity and morphological, chemical and crystallographic similarities to the bone apatite. The aim of the present work has been the synthesis and characterization of two calcium phosphates with Ca/P=1.5 e 1.67 as molar ratio. These were synthesized through the chemical wet process. After synthesis, the hydrated calcium phosphate powders were subsequently calcined at temperatures of 900 ºC/2 h providing b-calcium phosphate (b-TCP) and hydroxyapatite (HA) powders. These powders were used to elaborate the biphasic powders in the wt.% ratios HA/b-TCP as follows: 80/20, 20/80, 70/30 and 30/70. The method used for the elaboration of the b-tricalcium phosphate nanostructured powder, hydroxyapatite and biphasic compositions was the attrition milling. The nanostructured powders obtained were characterized by the scanning electron microscopy technique, X-ray diffractometry. Infrared spectroscopy and Specific surface using BET model.
2020
The incorporation of magnesium (Mg) in tricalcium phosphate (TCP) was prepared through a precipitation method followed by calcination at 850 °C in air. Calcium hydroxide, (Ca(OH)2), phosphoric acid, (H3PO4), and magnesium chloride (MgCl2.6H2O) with a Ca/P ratio of 1.5, were mixed as the precursor materials. The concentration of added Mg was varied with respect to calcium (Ca) precursor molarity as such Mg/(Ca +Mg) molar ratio was 0.05, 0.10, and 0.15, while the (Ca+Mg)/P ratio was maintained at 1.50 throughout the experiment. The influence of Mg-doped TCP on phase composition, chemical structure, and a functional group at different weight percentages were accomplished through X-ray diffraction (XRD), inductively coupled plasma optical emission spectroscopy (ICP-OES) and Fourier Transform Infrared Spectroscopy (FTIR) analyses. Based in the results of this research, the presence of magnesium led to the formation of Mg-doped calcium-deficient apatite (MgCDA) at 80°C and Mg-doped β-TCP ...
Mg2+ substituted calcium phosphate nano particles synthesis for non viral gene delivery application
Journal of Materials Science: Materials in Medicine, 2010
Gene therapy provides a unique approach to medicine as it can be adapted towards the treatment of both inherited and acquired diseases. Recently, calcium phosphate vectors as a new generation of the non viral gene delivery nano carriers have been studied because of their biocompatibility and DNA condensation and gene transfer ability. Substituting cations, like magnesium, affects physical and chemical properties of calcium phosphate nano particles. In this study, Mg 2? substituted calcium phosphate nano particles have been prepared using the simple sol gel method. X-ray diffraction analysis, Fourier transform infra red spectroscopy, transmission electron microscopy, specific surface area analysis, zeta potential measurement and ion release evaluation were used for characterization of the samples. It was concluded that presence of Mg ions decrease particle size and crystallinity of the samples and increase positive surface charge as well as beta tricalcium phosphate fraction in chemical composition of calcium phosphate. These properties result in increasing the DNA condensation ability, specific surface area and dissolution rate of the samples which make them suitable particles for gene delivery application.
Materials science & engineering. C, Materials for biological applications, 2015
As biocompatible materials, magnesium phosphates have received a lot of attention for orthopedic applications. During the last decade multiple studies have shown advantages for magnesium phosphate such as lack of cytotoxicity, biocompatibility, strong mechanical properties, and high biodegradability. The present study investigates the role of Mg(+2) and Ca(+2) ions in the structure of magnesium phosphate and calcium phosphate nanoparticles. To directly compare the effect of Mg(+2) and Ca(+2) ions on structure of nanoparticles and their biological behavior, three groups of nanoparticles including amorphous magnesium phosphates (AMPs) which release Mg(+2), calcium magnesium phosphates (CMPs) which release Mg(+2) and Ca(+2), and hydroxyapatites (HAs) which release Ca(+2) were studied. SEM, TEM, XRD, and FTIR were used to evaluate the morphology, crystallinity, and chemical properties of the particles. AMP particles were homogeneous nanospheres, whereas CMPs were combinations of heterog...