Investigation into the role of NaOH and calcium ions in the synthesis of calcium phosphate nanoshells (original) (raw)
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Preparation and Characterization of Calcium Phosphate Nanoparticles
Key Engineering Materials, 2003
INEB – Instituto de Engenharia Biomédica, Lab. de Biomateriais, Universidade do Porto, Rua do Campo Alegre, 823, 4150 -180 Porto, Portugal, cmmanuel@fe.up.pt Rensselaer Poly. Institute, Materials Science and Engineering Dep., Troy, NY, 12180-3590 USA, fosterm5@rpi.edu, doremr@rpi.edu Universidade do Porto, Faculdade de Engenharia, Dep. de Engenharia Metalúrgica e Materiais, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal E-mail: fjmont@fe.up.pt Universidade Fernando Pessoa, Faculdade de Ciências da Saúde, Rua Carlos da Maia, 296, 4200-150 Porto, Portugal, mpferraz@ufp.up.pt Rensselaer Poly. Institute, Department of Biomedical Engineering, Troy, NY, USA, bizios@rpi.edu
Calcium phosphate formation on TiO2 nanomaterials of different dimensionality
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2020
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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.
Anisotropic calcium phosphate nanoparticles coated with 2-carboxyethylphosphonic acid
The principles of nanoparticle synthesis established for semiconductors were used for preparation of anisotropic calcium phosphate dispersions, which could be essential for a number of bone-related biomedical applications. Calcium phosphate nanoparticles (CP NPs) with relatively high monodispersity were synthesized from aqueous calcium nitrate and phosphoric acid in the presence of 2-carboxyethylphosphonic acid (CEPA). They form stable colloidal solutions displaying minimal agglomeration. CP NPs are produced in a discoid shape with a diameter of 30–80 nm and a height of less than 5 nm. The predominant phase of the particles is brushite with some amount of apatite and amorphous calcium phosphate. Both structural and colloidal properties of the prepared nanocrystalline form of calcium phosphate make the particles suitable for further exploration for bone regeneration.
Ingeniería y Competitividad, 2017
Calcium phosphates are ceramics materials used in the manufacture of bone substitutes, due to their composition which is similar to the bones, they are bioactive, osteoconductivity and works in favor of forming porous structures, allowing vascularization and cell adhesion; furthermore they stand out for their biocompatibility. They are currently employed in the replacement of bone tissue in several clinical applications such as bone cements and fillers. Within this paper, nanoparticles of different calcium phosphates were obtained and characterized by two methods reported in the literature, centrifugation and hydrothermal treatment from precipitation reaction. The powders were characterized by XRD and FE-SEM. The results prove that both methods are suitable for the obtaining of nanoparticles of calcium phosphates, which is verified in the micrographs obtained where different morphologies are observed. Particles in nanoscale for most powders obtained have average diameter between 44.98 and 82.21 nm and average length between 123.91 and 151.48 nm. Diffractograms by both methods show the presence of calcium phosphates with different potential applications in bone tissue engineering, for the hydrothermal method was found that the temperature and time are major factors during stabilizing of phases. From this study it was concluded that both synthesis methods are suitable for obtaining nanoparticles and stabilization of different phases of calcium phosphate, being protocols 1, 3 and 4 the most suitable for biomedical applications
Mediterranean Journal of Chemistry, 2020
Apatitic calcium phosphates have a mineral phase close to that of bone and are commonly used as substitutes or fillers in bone surgery. Also, they are used for their excellent biocompatibility and bioactivity. The purpose of this study is to produce directly biphasic calcium phosphate (BCP) from calcium-deficient apatite (CDHA), by the hydrothermal process. The precursors used were calcium acetate (CH3COO)2 Ca, phosphoric acid (H3PO4) and triethylamine N (CH2CH3)3, the product was calcined at 900°C. The composition phase, morphology, particle size and the molecular structure of the product were studied using these techniques: X-Ray Diffraction techniques, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy, Fourier Transforms Infrared spectroscopy (FT-IR ) to reveal its phase content, Inductively Coupled Plasma-Atomic Emission Spectrometers (ICP-AES), Thermogravimetric analysis, Thermo-Differentials (ATG / ATD). The results showed that the synthesized product is CD...
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...
Liposome Directed Growth of Calcium Phosphate Nanoshells
Advanced Materials, 2002
In conclusion, a well-ordered mesoporous silica/gold nanocomposite was synthesized using a liquid phase self-assembly method. The silica matrix was highly crystalline with mesopores extending throughout the structure and pore volume and surface area were comparable with mesoporous silicate materials. Gold nanoparticles, 60 nm in diameter were preprepared and acted as seeds for the growth of the mesoporous silica shell. Therefore quantum size effects were controlled independently of the silica mesopore geometry. Work on the encapsulation of other nanoparticles, including, Fe, Pt, Ti, and cadmium(II) selenide materials is currently being undertaken.
Incorporation of Functionalized Calcium Phosphate Nanoparticles in Living Cells
Journal of Cluster Science
Intracellular calcium (Ca2+) is a key signaling element that is involved in a great variety of fundamental biological processes. Thus, Ca2+ deregulation would be involved in the cancer cell progression and damage of mitochondrial membrane and DNA, which lead to apoptosis and necrosis. In this study, we have prepared amorphous calcium phosphate nanoparticles (ACP NPs) for studied their incorporation by endocytosis or electroporation to epithelial, endothelial and fibroblast cells (MCF-7, HUVEC and COS-1 cells, respectively). Our results showed that internalized ACP NPs have cytotoxic effects as a consequence of the increase of the intracellular calcium content. The endocytosis pathways showed a greater cytotoxic effect since calcium ions could easily be released from the nanoparticles and be accumulated in the lysosomes and mitochondria. In addition, the cytotoxic effect could be reversed when calcium ion was chelated with ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic ...
Ceramic Engineering and Science Proceedings, 2014
An inorganic solution similar to the inorganic electrolyte compartment of the DMEM (Dulbecco's modified Eagle medium) cell culture medium is developed. This biomineralization medium contains 44.05 mM HCO 3-, 126.86 mM Na + , 93.37 mM Cl-, 5.33 mM K + , 2.26 mM Ca 2+ , 0.905 mM H 2 PO 4-, and 0.81 mM Mg 2+. Its Ca/P molar ratio is set to be identical with that of human blood plasma, i.e., 2.50. The medium is free of any Tris or Hepes but maintains a pH of 7.45 both at 37 and 65°C. The first novelty of this solution is it has the unique ability to homogeneously coat X-ray-amorphous calcium phosphate (ACP) on glass slides vertically immersed in it and kept at 37°C for less than 48 h. The second innovative aspect of this solution is it has the unprecedented ability to produce monodisperse ACP nanospheres with diameters of about 180 nm when simply heated at 65°C for 1 h while being stirred. The third novelty of this solution is it only forms ACP and it does not form apatite in stark contrast to many other synthetic calcification or biomineralization solutions (media) known. Samples were characterized by XRD, FTIR, EDXS, BET, SEM, TEM, ICP-AES and contact angle goniometry.