Detailed characterization of the Ti-O based thin films obtained by cathodic arc evaporation

Physicochemical properties of thin films on the base of titanium oxides, obtained by a cathodic arc evaporation on the surface of glass substrate are analysed in details. The analysis of these films was made by using XRD, FTIR, SEM, XPS analysis and ellipsometry. On the basis of these analyses, particularly analysis obtained by XPS, the oxidative state Ti and corresponding phases are determined through various film layers from the surface to the substrate. The depth of the various levels and their extinction coefficients and refractory indexes are estimated by ellipsometry

Biocompatibility and cytotoxicity study of nanophotonic rigid gas permeable contact lens material

Since materials on nanoscale have different characteristics from materials on macro scale their biocompatibility should be precisely and specifically investigated. Fullerenes, the third carbon allotrope, are one of the most used nanomaterials. The least stable and the most common is fullerene C-60. One of the main disadvantages of fullerene is its low solubility in water. In order to make it soluble, it must be functionalized with polar groups such as -OH and -COOH. From all the water soluble fullerenes the most important ones are those with -OH groups attached named fullerols. We have developed new materials for contact lenses by adding fullerene (C-60) and fullerol (C-60(OH)(24)) into PMMA. The aim of our investigation was to compare the influences of those materials on aqueous solutions similar to tear film. For the analysis of the solutions we used opto-magnetic imaging and IR spectroscopy. The acquired spectrums were commented and compared with the standard contact lens material, which was analyzed by the same methods. The ISO 10993 cytotoxicity test on extract of nanophotonic material with incorporated C-60 was done as well. This research contributes to better understanding of the biocompatibility of new rigid gas permeable contact lens materials

Biological aspects of application of nanomaterials in tissue engineering

Millions of patients worldwide need surgery to repair or replace tissue that has been damaged through trauma or disease. To solve the problem of lost tissue, a major emphasis of tissue engineering (TE) is on tissue regeneration. Stem cells and highly porous biomaterials used as cell carriers (scaffolds) have an essential role in the production of new tissue by TE. The cellular component is important for the generation and establishment of the extracellular matrix, while a scaffold is necessary to determine the shape of the newly formed tissue and facilitate migration of cells into the desired location, as well as their growth and differentiation. This review describes the types, characteristics and classification of stem cells. Furthermore, it includes functional features of cell carriers - biocompatibility, biodegradability and mechanical properties of biomaterials used in developing state-of-the-an scaffolds for TE applications, as well as suitability for different tissues. Moreover, it explains the importance of nanotechnology and defines the challenges and the purpose of future research in this rapidly advancing field

High temperature sintering kinetics of a-Al2o3 powder

The sintering kinetics of a-Al2O3 powder is investigated in this paper Commercial a-Al2O3 powdered compacts were sintered close to 95 % of the theoretical density. The characteristic parameters of sintering kinetics were also determined

Biocompatibility of a new nanomaterial based on calcium silicate implanted in subcutaneous connective tissue of rats

The aim of the study was to investigate rat connective tissue response to a new calcium silicate system 7, 15, 30 and 60 days after implantation. Twenty Wistar albino male rats received two tubes half-filled with a new calcium silicate system (NCSS) or MTA in subcutaneous tissue. The empty half of the tubes served as controls. Five animals were sacrificed after 7, 15, 30 and 60 days and samples of the subcutaneous tissue around implanted material were submitted to histological analysis. The intensity of inflammation was evaluated based on the number of inflammatory cells present. Statistical analysis was performed using one way ANOVA and Holm Sidak's multiple comparison tests. Mild to moderate inflammatory reaction was observed after 7, 15 and 30 days around a NCSS while mild inflammatory reaction was detected after 60 days of implantation. In the MTA group, mild to moderate inflammatory reaction was found after 7 and 15 days while mild inflammatory reaction was present after 30 and 60 days. There was no statistically significant difference in the intensity of inflammatory reactions between the tested materials and control groups in any experimental period (ANOVA p>0.05). Regarding the intensity of inflammatory reactions at different experimental periods, a statistically significant difference was observed between 7 and 30 days, 7 and 60 days and 15 to 60 days for both materials. For the controls, a statistically significant difference was found between 7 and 60 days and 15 and 60 days of the experiment (Holm Sidak < p 0.001). Subcutaneous tissue of rats showed good tolerance to a new calcium silicate system. Inflammatory reaction was similar to that caused by MTA. [Projekat Ministarstva nauke Republike Srbije, br. 172026

Determination of nickel content in the semimembranosus muscle of pigs produced in Vojvodina

The content of nickel was investigated in the M. semimembranosus of sixty-nine pigs from ten different genetic lines produced in Vojvodina. Nickel was determined by flame atomic absorption spectrometry after mineralization by dry ashing. The difference in the nickel content in the analyzed muscle tissues among different genetic lines of pigs was not significant (P > 0.05). Nickel levels ranged from 12.93 to 80.18 μg/100 g, with a general average of 32.41 μg/100 g. The average level of nickel was found to be higher than the levels observed in pork in some developed countries

Cytotoxicity investigation of a new hydroxyapatite scaffold with improved structural design

Introduction Biodegradable porous scaffolds are found to be very promising bone substitutes, acting as a temporary physical support to guide new tissue regeneration, until the entire scaffold is totally degraded and replaced by the new tissue. Objective The aim of this study was to investigate cytotoxicity of a synthesized calcium hydroxyapatite-based scaffold, named ALBO-OS, with high porosity and optimal topology. Methods The ALBO-OS scaffold was synthesized by the method of polymer foam template. The analysis of pore geometry and scaffold wallstopography was made by scanning electron microscope (SEM). The biological investigations assumed the examinations of ALBO-OS cytotoxicity to mouse L929 fibroblasts, using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromidefor (MU) and lactate dehydrogenase (LDH) tests and inverse phase microscopy. Results The SEM analysis showed high porosity with fair pore distribution and interesting morphology from the biological standpoint. The biological investigations showed that the material is not cytotoxic to L929 cells. Comparison of ALBO-OS with Bio-Oss, as the global gold standard as a bone substitute, showed similar results in MTT test, while LDH test showed significantly higher rate of cell multiplication with ALBO-OS. Conclusion The scaffold design from the aspect of pore size, distribution, and topology seems to be very convenient for cell adhesion and occupation, which makes it a promising material as a bone substitute. The results of biological assays proved that ALBO-OS is not cytotoxic for L929 fibroblasts. In comparison with Bio-Oss, similar or even better results were obtained

In Vivo Investigation of ALBO-OS Scaffold Based on Hydroxyapatite and PLGA

A synthetic bone substitute based on calcium hydroxyapatite (CHA) and poly(lactic-co-glycolic) acid (PLGA), described in this paper, was synthesized to fulfill specific requirements like biodegradability, satisfying mechanical properties, optimal porosity and nanotopology, osteoinductive and osteoconductive properties, and so forth. Structural and morphological properties of the new scaffold were analyzed by micro computed tomography and scanning electron microscopy, while its physicochemical properties were investigated by X-ray diffraction and infrared spectroscopy. In vivo biological investigations of the synthesized scaffold were conducted over the cutaneous irritation and biofunctionality assays on rabbits and the test of acute systemic toxicity on mice. The results showed that the scaffold is not irritant and that it does not exhibit any symptoms of acute toxicity. Biofunctionality assays which include evaluation of the presence of various cells of immune response, the presence of neoangiogenesis, percentage of mineralization of newly formed bone, and fibroplasia in the tissue indicated that the new scaffold is suitable for the application in maxillofacial and dental surgery as a bone substitute. Also, it showed significant advantages over commercial product Geistlich Bio-Oss(R) from the aspect of some parameters of immunological response

Design of Li phosphorous doped bronzes obtained by using spray pyrolysis

The ultrasonic spray pyrolysis technique has been, during last three decades, one of the major techniques of synthesis a wide variety of materials. One of the most important among the ionic conductors is lithium phosphorous doped tungsten bronze. The main goal of this investigation is producing full or hallows spheres of these bronzes of very narrow distribution. The mean size and size distribution specter of all materials were determined by the SEM analysis. The results were compared with the values obtained from the theoretical model. The assembled results indicate the possibility of a rigorous particle structure designing of all obtained powders.17th International Vacuum Congress/13th International Conference on Surface Science/International Conference on Nanoscience and Technology, Jul 02-06, 2007, Stockholm, Swede

Modelling and experimental investigations of thin filmsof Mg phosphorus-doped tungsten bronzes obtainedby ultrasonic spray pyrolysis

In this study, the synthesis of thin films of Mg phosphorus doped tungsten bronzes (MgPTB; MgHPW(12)O(40).29H(2)O) by the self-assembly of nano-structured particles of MgPTB obtained using the ultrasonic spray pyrolysis method was investigated. As the precursor, MgPTB, prepared by the ionic exchange method, was used. Nano-structured particles of MgPTB were obtained using the ultrasonic spray pyrolysis method. The nano-structure of the particles used as the building blocks in the MgPTB thin film were investigated experimentally and theoretically, applying the model given in this article. The obtained data for the mean particle size and their size distribution show a high degree of agreement. These previously tailored particles used for the preparation of thin films during the next synthesis step, by their self-assembly over slow deposition on a silica glass substrate, show how it is possible to create thin MgPTB films under advance projected conditions of the applied physical fields with a fully determined nanostructure of their building block particles, with a relatively small roughness and unique physical properties