Structural and physical properties of antibacterial Ag-doped nano-hydroxyapatite synthesized at 100°C

Synthesis of nanosized particle of Ag-doped hydroxyapatite with antibacterial properties is in the great interest in the development of new biomedical applications. In this article, we propose a method for synthesized the Ag-doped nanocrystalline hydroxyapatite. A silver-doped nanocrystalline hydroxyapatite was synthesized at 100°C in deionized water. Other phase or impurities were not observed. Silver-doped hydroxyapatite nanoparticles (Ag:HAp) were performed by setting the atomic ratio of Ag/[Ag + Ca] at 20% and [Ca + Ag]/P as 1.67. The X-ray diffraction studies demonstrate that powders made by co-precipitation at 100°C exhibit the apatite characteristics with good crystal structure and no new phase or impurity is found. The scanning electron microscopy (SEM) observations suggest that these materials present a little different morphology, which reveals a homogeneous aspect of the synthesized particles for all samples. The presence of calcium (Ca), phosphor (P), oxygen (O), and silver (Ag) in the Ag:HAp is confirmed by energy dispersive X-ray (EDAX) analysis. FT-IR and FT-Raman spectroscopies revealed that the presence of the various vibrational modes corresponds to phosphates and hydroxyl groups. The strain of Staphylococcus aureus was used to evaluate the antibacterial activity of the Ca10-xAgx(PO4)6(OH)2 (x = 0 and 0.2). In vitro bacterial adhesion study indicated a significant difference between HAp (x = 0) and Ag:HAp (x = 0.2). The Ag:Hap nanopowder showed higher inhibition

Iron Oxide Magnetic Nanoparticles: Characterization and Toxicity Evaluation by In Vitro

The aim of this study was to evaluate the biological properties of iron oxide nanoparticles (IO-NPs) obtained in the aqueous suspension. The iron oxide nanoparticles were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The biocompatibility of the iron oxide was demonstrated by the in vitro quantification of HeLa cells viability using propidium iodide (PI) and fluorescein diacetate (FdA) and the MTT colorimetric assay. The toxicity of small size iron oxide nanoparticles was also evaluated by means of histological examination on male Brown Norway rats after intraperitoneal injection. At the tested concentrations, the nanoparticles proved to be not cytotoxic on HeLa cells. The rat’s behavior, as well as the histopathological aspect of liver, kidney, lung, and spleen tissues at 48 h after intraperitoneal injection did not present any modifications. The in vivo and in vitro assays suggested that the IO-NPs could be further used for developing new in vivo medical applications

Synthesis, Structure, and Luminescent Properties of Europium-Doped Hydroxyapatite Nanocrystalline Powders

The luminescent europium-doped hydroxyapatite (Eu:HAp, Ca10−xEux(PO4)6(OH)2) with 0≤x≤0.2 nanocrystalline powders was synthesized by coprecipitation. The structural, morphological, and textural properties were well characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The vibrational studies were performed by Fourier transform infrared, Raman, and photoluminescence spectroscopies. The X-ray diffraction analysis revealed that hydroxyapatite is the unique crystalline constituent of all the samples, indicating that Eu has been successfully inserted into the HAp lattice. Eu doping inhibits HAp crystallization, leading to a decrease of the average crystallite size from around 20 nm in the undoped sample to around 7 nm in the sample with the highest Eu concentration. Furthermore, the samples show the characteristic 5D0→7F0 transition observed at 578 nm related to Eu3+ ions distributed on Ca2+ sites of the apatitic structure

Biomedical properties and preparation of iron oxide-dextran nanostructures by MAPLE technique

<p>Abstract</p> <p>Background</p> <p>In this work the chemical structure of dextran-iron oxide thin films was reported. The films were obtained by MAPLE technique from composite targets containing 10 wt. % dextran with 1 and 5 wt.% iron oxide nanoparticles (IONPs). The IONPs were synthesized by co-precipitation method. A KrF* excimer laser source (λ = 248 nm, τ_FWHM≅25 ns, ν = 10 Hz) was used for the growth of the hybrid, iron oxide NPs-dextran thin films.</p> <p>Results</p> <p>Dextran coated iron oxide nanoparticles thin films were indexed into the spinel cubic lattice with a lattice parameter of 8.36 Å. The particle sized calculated was estimated at around 7.7 nm. The XPS shows that the binding energy of the Fe 2p_3/2of two thin films of dextran coated iron oxide is consistent with Fe³⁺oxides. The atomic percentage of the C, O and Fe are 66.71, 32.76 and 0.53 for the films deposited from composite targets containing 1 wt.% maghemite and 64.36, 33.92 and 1.72 respectively for the films deposited from composite targets containing 5 wt.% maghemite. In the case of cells cultivated on dextran coated 5% maghemite γ-Fe₂O₃, the number of cells and the level of F-actin were lower compared to the other two types of thin films and control.</p> <p>Conclusions</p> <p>The dextran-iron oxide continuous thin films obtained by MAPLE technique from composite targets containing 10 wt.% dextran as well as 1 and 5 wt.% iron oxide nanoparticles synthesized by co-precipitation method presented granular surface morphology. Our data proved a good viability of Hep G2 cells grown on dextran coated maghemite thin films. Also, no changes in cells morphology were noticed under phase contrast microscopy. The data strongly suggest the potential use of iron oxide-dextran nanocomposites as a potential marker for biomedical applications.</p

Biomedical Properties and Preparation of Iron Oxide-Dextran Nanostructures by MAPLE Technique

Background: In this work the chemical structure of dextran-iron oxide thin films was reported. The films were obtained by MAPLE technique from composite targets containing 10 wt. % dextran with 1 and 5 wt.% iron oxide nanoparticles (IONPs). The IONPs were synthesized by co-precipitation method. A KrF* excimer laser source (λ = 248 nm, τFWHM≅25 ns, ν = 10 Hz) was used for the growth of the hybrid, iron oxide NPs-dextran thin films. Results: Dextran coated iron oxide nanoparticles thin films were indexed into the spinel cubic lattice with a lattice parameter of 8.36 Å. The particle sized calculated was estimated at around 7.7 nm. The XPS shows that the binding energy of the Fe 2p3/2 of two thin films of dextran coated iron oxide is consistent with Fe3+ oxides. The atomic percentage of the C, O and Fe are 66.71, 32.76 and 0.53 for the films deposited from composite targets containing 1 wt.% maghemite and 64.36, 33.92 and 1.72 respectively for the films deposited from composite targets containing 5 wt.% maghemite. In the case of cells cultivated on dextran coated 5% maghemite γ-Fe2O3, the number of cells and the level of F-actin were lower compared to the other two types of thin films and control. Conclusions: The dextran-iron oxide continuous thin films obtained by MAPLE technique from composite targets containing 10 wt.% dextran as well as 1 and 5 wt.% iron oxide nanoparticles synthesized by co-precipitation method presented granular surface morphology. Our data proved a good viability of Hep G2 cells grown on dextran coated maghemite thin films. Also, no changes in cells morphology were noticed under phase contrast microscopy. The data strongly suggest the potential use of iron oxide-dextran nanocomposites as a potential marker for biomedical applications

Fabrication of Novel Chitosan&ndash;Hydroxyapatite Nanostructured Thin Films for Biomedical Applications

In this study, we develop chitosan&ndash;hydroxyapatite (CS&ndash;HAp) composite layers that were deposited on Si substrates in radio frequency (RF) magnetron sputtering discharge in argon gas. The composition and structure of CS&ndash;HAp composite layers were investigated by analytical techniques, such as Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), metallographic microscopy (MM), and atomic force microscopy (AFM). On the other hand, in the present study the second order derivative of FT-IR&ndash;ATR spectra, for compositional analyses of CS&ndash;HAp, were used. The SEM, MM, and AFM data have shown the formation of CS&ndash;HAp composite layers. The surface of CS&ndash;HAp composite layers showed uniform growth (at an Ar gas working pressure of p = 2 &times; 10&minus;3 mbar). The surface of the CS&ndash;HAp composites coatings became more nanostructured, becoming granular as the gas pressure increased from 5 &times; 10&minus;3 to 1.2 &times; 10&minus;2 mbar. However, our studies revealed that the surface morphology of the CS&ndash;HAp composite layers varies with the Ar gas working pressure. At the same time, optical properties are slightly influenced by Ar pressure. Their unique physicochemical properties make them suitable for various applications in the biomedical field, if we consider the already proven antimicrobial properties of chitosan. The antifungal properties and the capacity of the CS&ndash;HAp composite layers to inhibit the development of fungal biofilms were also demonstrated using the Candida albicans ATCC 10231 (C. albicans) fungal strain

Physico-Chemical Properties and In Vitro Antifungal Evaluation of Samarium Doped Hydroxyapatite Coatings

Hydroxyapatite (HAp) and samarium doped hydroxyapatite, Ca10&minus;xSmx(PO4)6(OH)2, xSm = 0.05, (5SmHAp), coatings were prepared by sol-gel process using the dip coating method. The stability of 5SmHAp suspension was evaluated by ultrasound measurements. Fourier transform infrared spectroscopy (FTIR) was used to examine the optical characteristics of HAp and 5SmHAp nanoparticles in suspension and coatings. The FTIR analysis revealed the presence of the functional groups specific to the structure of hydroxyapatite in the 5SmHAp suspensions and coatings. The morphology of 5SmHAp nanoparticles in suspension was evaluated by transmission electron microscopy (TEM). Moreover, scanning electron microscope (SEM) was used to evaluate the morphology of nanoparticle in suspension and the morphology of the surface on the coating. The SEM and TEM studies on 5SmHAp nanoparticles in suspension showed that our samples consist of nanometric particles with elongated morphology. The SEM micrographs of HAp and 5SmHAp coatings pointed out that the coatings are continuous and homogeneous. The surface morphology of the 5SmHAp coatings was also assessed by Atomic Force Microscopy (AFM) studies. The AFM results emphasized that the coatings presented the morphology of a uniformly deposited layer with no cracks and fissures. The crystal structure of 5SmHAp coating was characterized by X-ray diffraction (XRD). The surface composition of 5SmHAp coating was analyzed by X-ray photoelectron spectroscopy (XPS). The XRD and XPS analysis shown that the Sm3+ ions have been incorporated into the 5SmHAp synthesized material. The antifungal properties of the 5SmHAp suspensions and coatings were studied using Candida albicans ATCC 10231 (C. albicans) fungal strains. The quantitative results of the antifungal assay showed that colony forming unity development was inhibited from the early phase of adherence in the case of both suspensions and coatings. Furthermore, the adhesion, cell proliferation and biofilm formation of the C. albicans were also investigated by AFM, SEM and Confocal Laser Scanning Microscopy (CLSM) techniques. The results highlighted that the C. albicans adhesion and cell development was inhibited by the 5SmHAp coatings. Moreover, the data also revealed that the 5SmHAp coatings were effective in stopping the biofilm formation on their surface. The toxicity of the 5SmHap was also investigated in vitro using HeLa cell line

Sm:HAp Nanopowders Present Antibacterial Activity against Enterococcus faecalis

The synthesis of nanoparticles with inhibitory and bactericidal effects represents a great interest in development of new materials for biological applications. In this paper we present for the first time the synthesis of Ca10-xSmx(PO4)6(OH)2 nanoparticles at low temperature and primary tests concerning the adherence of Enterococcus faecalis ATCC 29212 (gram-positive bacteria). All the XRD peaks were indexed in accordance with the hexagonal HAp in P63m space group. The EDAX spectrum and elemental mapping of O, P, Ca, and Sm demonstrate that all the elements were homogeneously distributed in Ca10-xSmx(PO4)6(OH)2 with xSm=0.03. The peaks at 347.3 eV, 532.1 eV, and 133.8 eV in the XPS spectra can be attributed to the binding energy of Ca 2p, O 1s, and P 2p. The peak at 1084.4 eV observed in Ca10-xSmx(PO4)6(OH)2 was attributed to the Sm 3d5/2. Bacterial adhesion was reduced on Ca10-xSmx(PO4)6(OH)2 sample when compared to pure HAp (xSm=0) and significant differences in bacterial adhesion on pure HAp (x=0) and Sm:HAp (xSm=0.01, xSm=0.03, and xSm=0.1) were observed. The bacterial adhesion decreased when the samarium concentrations increased. Finally, we demonstrate that the Sm:HAp nanopowder with xSm>0 showed high antibacterial activity against Enterococcus faecalis ATCC 29212

Influence of the Biological Medium on the Properties of Magnesium Doped Hydroxyapatite Composite Coatings

In this paper, the stability of magnesium-doped hydroxyapatite/chitosan (MHC) suspension obtained with the sol-gel approach was evaluated using nondestructive ultrasound measurements. The MHC coatings obtained by the spin-coating technique were characterized before and after immersion for 7 and 14 days, respectively, in Dulbecco’s modified eagle medium (DMEM) by scanning electron microscopy, equipped with an EDAX detector. Also, the functional groups present on the MHC coatings surface were analyzed with the aid of attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy. The surface microstructure was evaluated using two commentary techniques, namely atomic force microscopy (AFM) and metallographic microscopy (MM). The influence of immersion in DMEM on the biological properties was studied with in vitro studies using primary osteoblast and HCT-8 cell lines. Our results revealed that both surface morphology and chemical composition of the MHC coatings allow rapid development of a new apatite layer on their surface after immersion in DMEM. Preliminary in vitro biological studies underlined the noncytotoxic effect of the studied samples on the proliferation of primary osteoblast and HCT-8 cell lines, which makes them a promising candidate for applications in fields such as orthopedics or dentistry. The antifungal assay of the MHC coatings was assessed using Candida albicans ATCC 10231 and their results showed a good inhibitory effect. The coatings made on the basis of the MHC composite could contribute to increasing the degree of success of implants by decreasing the risk of infections and postoperative inflammation