Investigation into the role of NaOH and calcium ions in the synthesis of calcium phosphate nanoshells
01 Mar 2012-Brazilian Journal of Chemical Engineering (Brazilian Society of Chemical Engineering)-Vol. 29, Iss: 1, pp 147-158
TL;DR: In this paper, negatively charged liposomes (1,2-dioleoyl-sn-glycero-3-phosphate sodium salt) were used as a template by base titration synthesis at various concentrations of NaOH and calcium ions.
Abstract: Calcium phosphate (CaP) nanoshells were prepared using negatively charged liposomes (1,2-dioleoyl-sn-glycero-3-phosphate sodium salt (DOPA)) as a template by base titration synthesis at various concentrations of NaOH and calcium ions. The elemental composition, morphology, particle size, particle size distribution and zeta potential of the products were determined via various characterisation techniques, such as energy-dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM), dynamic light scattering (DLS), laser Doppler velocimetry (LDV) and Fourier transform infrared spectroscopy (FTIR). The best results showed that stable spherical CaP nanoshells with a mean particle size of 197.5 ± 5.8 nm and a zeta potential of -34.5 ± 0.6 mV were successfully formed when 0.100 M sodium hydroxide (NaOH) and 0.100 M calcium ions were used. Moreover, an optimal pH of 10.52 and a final Ca/P molar ratio of 0.97 were achieved under these conditions.
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TL;DR: This chapter describes current state-of-the-art and recent developments on the subject of nanodimensional CaPO4, starting from synthesis and characterization to biomedical and clinical applications.
Abstract: Nano-scaled particles and crystals play very important roles in biological systems. For example, calcium orthophosphates (CaPO4) with nano-size dimensions represent the basic inorganic building blocks of bones and teeth of mammals. According to recent discoveries in biomineralization, zillions of nanodimensional crystals of biological apatites are nucleated in body fluids, and afterward, they are self-assembled into these complex structures. In addition, both a greater viability and a better proliferation of various types of cells have been detected on smaller crystals of CaPO4. All these effects are due to the higher surface-to-volume ratio, increased reactivity, and biomimetic morphologies of the nano-scaled particles. Thus, the nano-sized and nanocrystalline forms of CaPO4 have a great potential to revolutionize the hard tissue engineering field, starting from bone repair and augmentation to controlled drug delivery systems. Therefore, preparation and application of nanodimensional CaPO4 are the important topics in modern material science, and such formulations have been already tested clinically for various purposes. Currently, more efforts are focused on the possibility of combining nano-scaled CaPO4 with cells, drugs, and other biologically active substances for multipurpose applications. This chapter describes current state-of-the-art and recent developments on the subject, starting from synthesis and characterization to biomedical and clinical applications.
55 citations
01 Jan 2018
TL;DR: In this chapter, a further understanding of the chemical, physical, and biological properties of CPC, along with the clinical applications, is addressed to provide a deeper insight into the regulation mechanism between the material properties and the clinical uses.
Abstract: Calcium phosphate cement (CPC) has opened up a new era in the construction of bone-related defects in biomedical fields. Such unique properties as the easy shaping, injectability in practical use, excellent biocompatibility, and biodegradability of CPC make it a perfect substitution material and maintain the research focus during the years. In this chapter, the brief history, classification, setting mechanism, and kinetics of CPC are introduced. A further understanding of the chemical, physical, and biological properties of CPC, along with the clinical applications, is also addressed to provide a deeper insight into the regulation mechanism between the material properties and the clinical uses.
29 citations
TL;DR: Results suggested that functionally graded bilayered membranes hold potential for GBR applications in regenerative dentistry.
Abstract: Barrier membranes are used in periodontal tissue engineering for successful neo-bone tissue formation and prevention of bacterial colonization. We aimed to prepare and characterize novel 7% boron-modified bioactive glass (7B-BG) containing bilayered membrane for this end. We hypothesized that presence of 7B-BG could promote structural and biological properties of guided bone regeneration (GBR) membrane. Cellulose acetate (CA) layer was prepared by solvent casting, and functionally graded layer of CA/gelatin/BG nanoparticles was prepared by electrospinning. 0B-BG, and 7B-BG were synthesized by quick alkali-mediated sol-gel method and were characterized by scanning electron microscopy (SEM) and Fourier-transform Raman spectroscopy. Membranes were cross-linked with glutaraldehyde to preserve their stability. SEM analysis showed the asymmetric nature of membranes consisting of a smooth membrane layer and a rough surface composed of 0B-BG and 7B-BG containing nanofibres. 7B-BG addition increased surface wettability (from 110.5° ± 0.8 to 73.46° ± 7.6) and biodegradability of the membranes. Additionally, a significant increase in Ca-P layer formation was observed in 7B-BG containing group after 1-week incubation in stimulated body fluid. 7B-BG incorporation resulted in a decrease in tensile strength and Young's modulus values. Human dental pulp stem cells showed better attachment, spreading, and proliferation on 7B-BG containing bilayered membranes. Osteogenic differentiation analysis revealed higher alkaline phosphatase (ALP) enzyme activity of cells (~1.5-fold), higher intracellular calcium deposition (approximately twofold), and higher calcium deposition revealed by Alizarin red staining on 7B-BG containing bilayered membranes. Overall, results suggested that functionally graded bilayered membranes hold potential for GBR applications in regenerative dentistry.
23 citations
TL;DR: In this paper, different metal ions (i.e., Ag, Cu, Zn, and Mg) were doped into nano-hydroxyapatite (HAp) to improve the antibacterial activity.
Abstract: Earth-abundant mineral limestone obtained from North Sumatera, Indonesia, has been utilized to synthesize nano-hydroxyapatite (HAp). Although HAp is biocompatible to the human bone, its antibacterial activity is still very low. Herein, different metal ions (i.e., Ag, Cu, Zn, and Mg) were doped into HAp to improve the antibacterial activity. The as-synthesized HAp was characterized by X-ray ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), energy disperse spectroscopy (EDS), Fourier transmission infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET). The antibacterial test showed that the performance of HAp to inactivate bacterial growth was significantly improved after incorporating the metal ion dopants into HAp. Ag-HAp exhibited the highest activity toward E. coli and S. aureus with an antibacterial rate of 99.9 ± 0.1%, followed by Zn-HAp, Cu-HAp, and Mg-HAp.
13 citations
TL;DR: In this article, binary (ZnO)x(TiO2)1−x NPs were effectively blended by using thermal treatment technique, where Zinc nitrate and titanium(IV) propoxide with polyvinylpyrrolidone, PVP, were utilized to set up the samples.
Abstract: Numerous studies have explored the behaviors of ZnO–TiO2 nanoparticles resulting through various routes of fabrication. To date, the utilization of thermal treatment method to convey ZnO–TiO2 nanoparticles has never been considered. In the present study, binary (ZnO)x(TiO2)1−x NPs were effectively blended by using thermal treatment technique. Zinc nitrate and titanium(IV) propoxide with polyvinylpyrrolidone, PVP, were utilized to set up the samples. Energy-dispersive X-ray (EDX) spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction (XRD) spectroscopy, ultraviolet–visible (UV–Vis) spectrophotometer transmission electron microscopy (TEM) and photoluminescence spectroscopy were utilized to examine the impact of changing the molar proportion to the structure and optical features of (ZnO)x(TiO2)1−x NPs. The XRD spectra revealed that after calcination, the amorphous sample had transformed into crystalline nanoparticles. The prepared (ZnO)x(TiO2)1−x NPs average diameter was around 25.922–28.531 nm according to TEM analysis. The analyzation of UV–Vis spectroscopy determined the optical measurements parameters including the energy gap and Urbach energy of binary (ZnO)x(TiO2)1−x NPs. The optical energy gap varied in the range of 3.2496–3.2863 eV as the molar ratio increases from x = 0.24 to x = 0.72. The enhancement within the nanoparticles optical properties suggests a good potential for photocatalysis application.
9 citations
References
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TL;DR: A review is presented of the scientific literature concerning precipitate formation during setting reactions of CPBCs and it is shown that understanding the thermodynamics of calcium phosphate salts in an aqueous solution at room or body temperature it is possible to optimize the manufacturing technology involved in the production ofCPBCs.
Abstract: Calcium phosphate bone cements (CPBC) have been of great interest in medicine and dentistry due to their excellent biocompatibility and bone-repair properties. In this article, a review is presented of the scientific literature concerning precipitate formation during setting reactions of CPBCs. Firstly, the available information has been classified according to the intended final product or calcium phosphate formed during setting reactions. Taking the final product into account, a second classification has been made according to the calcium phosphates present in the original powder mixture. This is the most natural classification procedure because it is based on thermodynamic reasons supported by solubility diagrams for the calcium phosphate salts. By understanding the thermodynamics of calcium phosphate salts in an aqueous solution at room or body temperature it is possible to optimize the manufacturing technology involved in the production of CPBCs. Knowledge of the limitations of this thermodynamic approach opens up new possibilities in the search for CPBCs with better in vitro and in vivo properties for clinical applications.
155 citations
"Investigation into the role of NaOH..." refers background in this paper
...There are many phases of CaPs, which exhibit different crystal structures and Ca/P molar ratios (Fernández et al., 1999a; Fernández et al., 1999b; Dorozhkin, 2009)....
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TL;DR: In this article, the nucleation sites of calcium phosphate crystals during collagen mineralization were studied by Fourier transform infrared spectrometry and transmission electron microscopy, and it was found for the first time that there is another nucleation site, i.e., carbonyl (>C=O) on collagen, besides the previous reported carboxyl (-COOH).
Abstract: The nucleation sites of calcium phosphate crystals during collagen mineralization were studied by Fourier transform infrared spectrometry and transmission electron microscopy. It was found for the first time that there is another nucleation site, i.e., carbonyl (>C=O) on collagen, besides the previous reported nucleation site of carboxyl (-COOH). By comparing the IR spectra of collagen not only with collagen/calcium phosphate but also with collagen/Ca 2+ , it was observed that the peak intensities of amides I, II, and III of collagen decreased significantly after mineralization. The decrease of the amide I peak intensity was mainly due to blockage of the C=O stretch. Furthermore, the peak for amide I gradually shifted to a lower wavenumber during collagen mineralization. This shift indicated that chemical interaction between carboxyl groups and Ca 2+ ions formed in the mineralization.
131 citations
"Investigation into the role of NaOH..." refers background in this paper
...=O) stretching vibrations appeared at approximately 1730 cm-1 (Dluhy et al., 1983; Zhang et al., 2003)....
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...Carbonyl group (C=O) stretching vibrations appeared at approximately 1730 cm (Dluhy et al., 1983; Zhang et al., 2003)....
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TL;DR: Hydroxyapatite (HA) coated liposomes (HACL) have been successfully manufactured and filled with a model hydrophobic (lipophilic) drug, indomethacin (IMC), and it has been observed that for uncoated liposome, IMC is released at a greater rate at pH=7.4 than at pH =4.4, but coating with HA reduced the rate at acidic conditions.
124 citations
"Investigation into the role of NaOH..." refers background in this paper
...Schmidt’s results indicated that the structures formed by the supersaturated mixtures were vitally influenced by the pH, which is directly controlled by NaOH addition (Xu et al., 2007)....
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TL;DR: In this paper, an electrochemical route for fabricating hydroxyapatite (HA), carbonated-HA and fluoridated-HA coatings on porous and non-porous substrates at relatively low temperatures, using aqueous electrolytes.
Abstract: The concept of biological fixation of artificial joint prosthesis by using bioactive calcium phosphate coatings has generated considerable interest in recent decades. This paper reports an electrochemical route for fabricating hydroxyapatite (HA), carbonated-HA and fluoridated-HA coatings on porous and non-porous substrates at relatively low temperatures, using aqueous electrolytes. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and infrared spectroscopy (IR) were used to characterize the morphology, structure and chemical composition of the coatings. The results suggest that the electrochemical route for the fabrication of bioactive calcium phosphate coatings may offer significant advantages over the currently used methods.
122 citations
"Investigation into the role of NaOH..." refers background in this paper
...On the contrary, for samples prepared with lower concentrations of calcium ions (C-DOPA-6 and C-DOPA-4), the peaks at 3550 cm-1 were invisible in the spectra, which further implies that both samples were poorly crystallised (Shirkhanzadeh, 1995; Chu and Liu, 2005)....
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...On the contrary, for samples prepared with lower concentrations of calcium ions (C-DOPA-6 and C-DOPA-4), the peaks at 3550 cm were invisible in the spectra, which further implies that both samples were poorly crystallised (Shirkhanzadeh, 1995; Chu and Liu, 2005)....
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TL;DR: In this paper, a synthesis strategy for aqueous-cored calcium phosphate nanoparticles is presented that combines ease of preparation, reproducibility, size control, stability, and mean thickness control.
Abstract: A synthesis strategy for aqueous-cored calcium phosphate nanoparticles is presented that combines ease of preparation, reproducibility, size control, stability, and mean thickness control. Suspensi...
116 citations
"Investigation into the role of NaOH..." refers background in this paper
...The negatively charged head group of DOPA liposomes assists in the localisation of ions around the spherical surface of the nanoshells (Schmidt et al., 2004)....
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...In addition, the fact that calcium ions are the main element of both CaPs and bone is another key to influencing electrostatic localisation on the DOPA liposome template and the growth of the CaPs on the liposome template (Schmidt et al., 2004)....
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...In addition, the fact that calcium ions are the main element of both CaPs and bone is another key to influencing electrostatic localisation on the DOPA liposome template and the growth of the CaPs on the liposome template (Schmidt et al., 2004)....
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...Calcium and phosphate ions began to localise around the negatively charged liposomes in this localisation stage (Schmidt et al., 2004)....
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