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: Ceramics can be composed of ions commonly found in the physiological environment and of ions showing limited toxicity to body tissue and the literature suggests that ceramics will play a major role as orthopedic implant materials.
23 citations
"Investigation into the role of NaOH..." refers background in this paper
..., calcium, sodium) (Hulbert et al., 1972) that are commonly found in the physiological environment (de Groot et al....
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...This non-toxicity is attributable to the fact that CaPs, which account for 69 wt % of bone, are composed of ions (e.g., calcium, sodium) (Hulbert et al., 1972) that are commonly found in the physiological environment (de Groot et al., 1990; Hench, 1998; Kalita et al., 2007)....
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TL;DR: In this paper, the authors used negatively charged liposomes (1,2 dioleoyl-sn-glycero-3 phosphate sodium salt (DOPA) and 1,2-dipalmitoyl -sn-glycero -3phosphate sodium salt(DPPA) as templates for the synthesis of CaP nanoshells.
23 citations
"Investigation into the role of NaOH..." refers background in this paper
...9 mV) (Yeo et al., 2012) , the magnitudes of all the zeta potentials decreased after the growth of CaPs on the liposomes....
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...The results show the growth of CaPs on the DOPA template: larger mean particle sizes were observed for the samples of CaP nanoshells compared with the DOPA template (64.7 ± 0.7 nm) (Yeo et al., 2012)....
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...…Engineering In addition, the mean zeta potentials of CaP nanoshells were in the range of -31.7 ± 1.0 mV to -56.0 ± 1.0 mV. Compared with the bare DOPA liposomes (-75.3 ± 2.9 mV) (Yeo et al., 2012) , the magnitudes of all the zeta potentials decreased after the growth of CaPs on the liposomes....
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TL;DR: Calcium enhanced the interactions of the model analytes with all coatings, and the interactions were then strongest with the POPC/PA coating, and in the presence of calcium there appears to be a slight reorganization of the coating with increasing number of runs.
21 citations
"Investigation into the role of NaOH..." refers background in this paper
...Calcium ions exhibit the ability to bind to phosphate groups of the DOPA template, which reduces the relative amount of free, negatively charged phosphate groups (Hautala et al., 2007)....
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...The negative charge of the DOPA liposome template was suppressed upon increasing of the concentration of calcium ions (Hautala et al., 2007)....
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...…the most significant change in the zeta potential value was observed in sample C-DOPA-4 (0.100 M NaOH and 0.100 M calcium ions), presumably due to the strong interactions between the calcium ions and the DOPA template, which are uniform in every direction in this sample (Hautala et al., 2007)....
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TL;DR: Hydroxyapatite (HAP)/liposome core–shell nanocomposites have been prepared at room temperature and rod-like whiskers obtained after separating the precipitates from the liposomes.
Abstract: Hydroxyapatite (HAP)/liposome core–shell nanocomposites have been prepared at room temperature. The liposome shells and the precipitate cores ranged in diameter mainly from 80 to 140 nm and from 40 to 120 nm, respectively. Rod-like whiskers ranging in length mainly from 10 to 30 nm were obtained after separating the precipitates from the liposomes. In contrast, the whiskers synthesized without liposomes ranged in length mainly from 70 to 140 nm. The precipitates synthesized both with and without liposomes were poorly crystalline, and had a similar chemical composition to the natural HAP.
21 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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...H modes attributed to absorbed water were observed at approximately 1650 cm-1 (Chu and Liu, 2005; Kumta et al., 2005)....
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TL;DR: Hydrophobic pyrene was encapsulated with an efficiency of 95%, at concentrations much higher than its water solubility limit, and exhibited spectral features characteristic of a hydrophobic environment.
Abstract: Hollow calcium phosphate nanoparticles capable of encapsulating poorly water-soluble molecules were produced by self-assembly. Previously reported were solid calcium phosphate nanoparticles and water-filled calcium phosphate nanocapsules suited for encapsulating mostly hydrophilic, but not hydrophobic compounds. Here, calcium phosphate was deposited around 100 nm diameter, 1,2-dioleoyl-sn-glycero-3-phosphate stabilized soybean oil nanoemulsions using either calcium chloride or NaOH titrations to achieve shell thickness between 20–70 nm. The surface was functionalized with carboxylic acid via the addition of carboxyethylphosphonic acid to attach Molecular Probes AB-594C antibody using sulpho-n-hydroxysuccinimide and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride with an efficiency of ∼70%, while retaining near complete antibody function. Hydrophobic pyrene was encapsulated with an efficiency of 95%, at concentrations much higher than its water solubility limit, and exhibited spectral features ...
21 citations
"Investigation into the role of NaOH..." refers background in this paper
...H bonds of the hydrocarbon chains (Dluhy et al., 1983) also produced peaks in the region of 2854 cm-1 and 2926 cm-1; this finding also reflects the use of the DOPA template (Schmidt et al., 2006)....
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...This last stage is the most important stage in the synthesis of CaP nanoshells because it is during this stage that the growth of CaPs on the liposomes occurs (Schmidt et al., 2006)....
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