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Catarina Marques,1 José MF Ferreira,1 Ecaterina Andronescu,2 Denisa Ficai,2 Maria Sonmez,3 Anton Ficai21Department of Materials and Ceramics Engineering, Centre for Research in Ceramics and Composite Materials, University of Aveiro, Aveiro, Portugal; 2Faculty of Applied Chemistry and Material Science, University Politehnica of Bucharest, Bucharest, Romania; 3National Research and Development Institute for Textiles and Leather, Bucharest, RomaniaAbstract: The purpose of this review is to present the most recent findings in bone tissue engineering. Special attention is given to multifunctional materials based on collagen and collagen–hydroxyapatite composites used for skin and bone cancer treatments. The multifunctionality of these materials was obtained by adding to the base regenerative grafts proper components, such as ferrites (magnetite being the most important representative), cytostatics (cisplatin, carboplatin, vincristine, methotrexate, paclitaxel, doxorubicin), silver nanoparticles, antibiotics (anthracyclines, geldanamycin), and/or analgesics (ibuprofen, fentanyl). The suitability of complex systems for the intended applications was systematically analyzed. The developmental possibilities of multifunctional materials with regenerative and curative roles (antitumoral as well as pain management) in the field of skin and bone cancer treatment are discussed. It is worth mentioning that better materials are likely to be developed by combining conventional and unconventional experimental strategies.Keywords: bone graft, cancer, collagen, magnetite, cytostatics, silver

The iron oxide nanoparticles were synthetized by an adapted coprecpitation method. Stuctural and morphological characterization of the obtained iron oxide nanoparticles were investigated by X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). Furthermore, in vitro and in vivo studies were investigated by cell viability assay and HeLa cells. For the analysis of iron oxide toxicity in vivo, several mice were treated with normal saline and iron oxide via intraperitoneal injection (IP). The XRD spectra showed the peaks associated to the spinel cubic lattice type with the lattice of 0.835 nm. By magnified TEM image, it could be observed that the samples have a uniform morphology with relatively spherical shape and nanometric size. Moreover, inverted fluorescence microscopy images of HeLa cells with normal phenotype and HeLa cells treated for 72 hourswith a suspension of γ-Fe2O3 nanoparticles revealed the non-toxic character. The histophtological studies have demonstrated that at 72 hours after IP administration, the iron oxide nanoparticles are not accumulating in kidney and spleen, thus establishing their utility as drug delivery systems targeted to these organs. [ABSTRACT FROM AUTHOR]

Magnetic iron oxide nanoparticles (MION) doped dextran thin films for biomedical applications have been deposited onto the glass substrate by spin coating method. To understand the influence of the MION doping dextran on physico-chemical properties was conducted. The particle concentration in the samples defined as the oxide/dextran mass ratio, R was 1 and 5. MION -dextran thin films were charcacterized by various techniques such as X-ray Photoelectron Spectroscopy (XPS), Glow Discharge Optical Emission Spectroscopy (GDOES), Scanning Electron Microscope (SEM) and Energy Dispersive Xray Attachment (EDAX). These techniques have allowed the structural elucidation of polysaccharides thin films. The second derivative FT-IR spectra showed clearly that the polysaccharides bands. The biocompatibility of the maghemite-dextran thin films was demonstrated using MTT test, with the aid of hFOB 1.19 osteoblats cells. To evaluate cell proliferation rate quantitative by the hFOB 1.19 cells on HAp samples were cultured to 4 days. Cellular morphology was investigated using FESEM to obtain qualitative information of osteoblast cells on MION-dextran thin films. The data stronlgy suggest the potential use of iron oxide-dextran nanocomposite as a poetinal marker for or biomedical applications. [ABSTRACT FROM AUTHOR]

Nanocrystalline ZnO particles were prepared from methanolic solutions of zinc acetate dihydrate without using base such as NaOH or LiOH through a colloid process carried out at a low temperature of 60oC. The precipitate obtained after 12-72h contained ZnO, covered with polymeric species of zinc hydroxo acetate. The reaction course was studied by mass spectrometry means. To complete the hydrolysis process, up to pure ZnO, it was necessarily to reflux the white precipitate separate from methanolic solution, in water at 80oC. We found that reaction time in the presence of methanol primarily influenced the size of the particles, while the reaction time in the presence of water mainly influenced the ZnO purity. [ABSTRACT FROM AUTHOR]

Europium doped hydroxyapatite (Eu:HAp) nanocristalline powders was synthesized by co-precipitation method by setting the atomic ratio of Eu/[Eu + Ca] at 0% and 2% and [Ca+Eu] /P at 1.67. The structural properties were characterized by X-ray diffraction (XRD). Nitrogen adsorption-desorption isotherms were obtained on different samples using BET method. 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. Based on N2 adsorption-desorption isotherms investigation, the pore size, surface area and pore volume of europium doped hydroxyapatite are 16.57 nm, 115.06 m2/g and 0.48 cm3/g. [ABSTRACT FROM AUTHOR]

Nano-hydroxyapatite bio-ceramics were synthesized by sol-gel method. The gel was dried at 80°C for 96 h. The dried gels were individually heated at a rate of 5°C/min up to 600°C, 800°C, and 1000°C. X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used for to characterize the composition, morphology and particle size of samples. At 800°C a small amount of CaO (about 0.3 wt%) was detected in which increased after annealing at 1000°C (about 1.1 wt%). The crystallites are elongated along the c crystallographic axis, but the size anisotropy decreases with increasing temperature above 800°C. The size along the elongation axis increased from 43 nm at 80°C to about 143 nm at 1000°C, as determined by XRD, and from 120 to 280 nm, as measured by TEM. The functional groups were analyzed using Fourier transform infrared (FTIR) and Raman spectroscopies confirming the presence of various and OH- bands in the samples. After calcination at 1000°C the bands are more intense which indicates an increase in the cristallynity. The photoluminescence (PL) of HAp treated at various temperatures (80, 600, 800, 1000°C) was also studied. hFOB 1.19 osteoblats cells were used to determine cell proliferation, viability and citotoxicity after interaction with the prepared bioceramics. To evaluate cell proliferation rate quantitative by the hFOB 1.19 cells on HAp samples were cultured to 4 days. Cellular morphology was investigated using FESEM to obtain qualitative information of osteoblast cells on HAp samples. The number of hFOB 1.19 cells on control HAp_80, HAp_600, HAp_800 and HAp_1000 was 400±30, 360±25, 350±21, 320±16 and 300±10 after 4 days. Our results proved that the HAp sintered at 1000°C promoted osteoblast cell attachment and adhesion. [ABSTRACT FROM AUTHOR]

The bio-compatible magnetic nanoparticles of maghemite were prepared by a chemical coprecipitation method and dextran was selected as the surfactant to suspend them. By transmission electron microscopy (TEM), the iron oxide nanoparticles appeared nearly spherical with an average diameter of about 8.0 ±1 nm. SAED pattern of iron oxide nanoparticles is indexed by a cubic γ-Fe2O3, the diffraction rings are attributed to the (220), (311), (400), (422), (511) and (440) planes, respectively. Regular fringes are clearly observed in the nanoparticle with a spacing of 0.24 nm , whigh is the (311) interplanar distance of the cubic maghemite. This is in perfect agreement with the X-Ray Diffraction (XRD) results, indicating that the nanoparticles are well crystallyzed in spite of their ultrafine sized. The attachment of the dextran on the particle surface was confirmed by Fourier Transform Infrared (FTIR) Spectroscopy. The biocompatibility of maghemite nanoparticles covered by dextran with HepG2 cells was checked by MTT test. Cell viability was > 98% when the iron concentration was 12.0 μg iron /ml and 24.0 μg iron /ml respectively. In conclusion, these nanoparticles presented a good biocompatibility with HepG2 cells, which was proportionally with the dilution level. [ABSTRACT FROM AUTHOR]

The Ba(Zn1/3Ta2/3)O3 (BZT) ceramic samples were prepared by solid-state reaction and sintered in the range 1550–1650°C for 2 h. Several methods—X-ray diffraction (XRD) and scanning electron microscopy (SEM)—were used for structural and morphological characterization. The unit cell distortion and the presence of the secondary phase content were studied by XRD. A long-range order with a 2:1 ratio of Ta and Zn cations on the octahedral positions of the perovskite structure was noticed with the increase of the sintering temperature. SEM investigations revealed polyhedral well-faceted grains and large grain size distribution. The dielectric properties in the microwave range were measured at room temperature and at 1 kHz on a large temperature interval (±150°C). The dielectric parameters were correlated with morphological and structural properties. Ceramic samples were annealed at 1410°C for 30 h to improve the microwave properties. The dielectric constant of BZT samples measured at 6 GHz and at 1 kHz was between 27 and 28 on the whole temperature range, that is, typical values for BZT material. The temperature coefficient of the resonance frequency at 6 GHz exhibits positive values less than 6 ppm/°C. [ABSTRACT FROM AUTHOR]

Abstract: The compounds YNi4−x Al x Mg with 0≤ x ≤1.5, crystallizing in the C15 structure type (MgCu4Sn-type), have been elaborated by mechanical milling and a subsequent heat treatment at 650°C for 1h. It was possible to synthesize the compounds YNi4−x Al x Mg with x up to approximately 1.15 and the lattice parameters was in good agreement with those already reported. All the samples, excepting the YNi4Mg compound, absorbed and desorbed hydrogen reversibly and no structural change is reported after the hydrogenation. A direct relationship between the lattice parameters and the equilibrium plateau pressure was found. [Copyright &y& Elsevier]

Abstract: The hydrogenation and dehydrogenation behaviours of the YNi3.5Al0.5Mg compound were studied by in situ X-ray diffraction under hydrogen pressure and at room temperature. The changes of (i) the lattice parameters, (ii) the crystallite size and (iii) the lattice strain during the sorption process (i.e. along the PC isotherms) were studied. These results indicate that the crystallite size decreases by a factor of 2. The micro deformations increase at first and then tend to almost zero at the end of the sorption cycle. This behaviour is explained in terms of co-existence of the metal (i.e. phase) and metal hydride (i.e. phase) phases. The change in crystallinity is consistent with the hydrogen induced amorphisation process existing in a lot of AB2 compounds. No anisotropic effects can be highlighted on this pseudo-AB2 compounds in contrary with what could be observed in AB5 compounds. [Copyright &y& Elsevier]