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Spoiala A.,Polytechnic University of Bucharest | Albu M.G.,National Research and Development Institute for Textiles and Leather INCDTP | Ficai A.,Polytechnic University of Bucharest | Andronescu E.,Polytechnic University of Bucharest | And 2 more authors.
Digest Journal of Nanomaterials and Biostructures | Year: 2014

Zinc oxide nanoparticles are known to have an effective antibacterial activity and silica based materials are widely used in many medical and cosmetic applications. Therefore, the SiO2 composite materials already synthesized through different methods and by including ZnO, will print an antibacterial activity to the cosmetic creams. The aim of this paper is to obtain cosmetic creams for solar protection from these antimicrobial composite materials based on SiO2/ ZnO. The composite materials were characterized by FTIR, SEM and by studying the antibacterial activity against S. aureus. © 2014, Inst Materials Physics. All rights reserved.

Popa C.L.,National Institute of Materials Physics Bucharest | Popa C.L.,University of Bucharest | Bartha C.M.,National Institute of Materials Physics Bucharest | Bartha C.M.,West University of Timisoara | And 9 more authors.
Digest Journal of Nanomaterials and Biostructures | Year: 2015

The goal of this study was to obtain at low temperature a functional nano-composite with characteristics similar to the natural bone by using a cost effective method. The structure and morphology of collagen coated zinc doped hydroxyapatite bio-composites (Zn:HAp-CBc) were examined by X-Ray diffraction (XRD) and Scanning Electron Microscopy (SEM). XRD analysis revealed that the unique hexagonal Ca10(PO4)6(OH)2 in P63m space group was observed in the obtained nanocomposites Zn:HAp-CBc. The cytotoxicity of the Zn:HAp-CBc was studied on HeLa cell lines. Cell cycle distribution after treatment was examined by flow cytometry analysis. Our preliminary in vitro studies revealed that the obtained composites based on Zn doped HAp embedded in collagen matrix have excellent biocompatibility and support their further characterization by in vivo approaches and development as a biomaterial used in bone regeneration. © 2015, Inst Materials Physics. All rights reserved.

Simion D.,National Research and Development Institute for Textiles and Leather INCDTP | Apetroaei M.,Ovidius University | Gaidau C.,National Research and Development Institute for Textiles and Leather INCDTP | Simion M.,National Research and Development Institute for Industrial Ecology | And 6 more authors.
International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM | Year: 2014

The aim of the paper is to create new biomaterials- biodegradable protein (Collagen)- based ”Core-Shell/Hollow” structural nano- SiO2 composite and to find applications for drug delivery system. These surfactant based composites can used for biomedical field, for ensure health and improvement of life quality. Biocompatibility between drugs and substrates (membranes, matrices, polymer films, hydrogels, creams, capsules, pearls, powders, nanoparticles) is a very important issue for the optimal prescription of different treatments for the human body and maintaining health. It was obtained biomaterials by immobilizing drugs on various polymeric substrates, establishing the optimal conditioning formula, both in the preparation phase and in the adsorption phase of active components on the substrate. These are structured nanoparticles which contain a core from one material (or hollow) and a protective shell from another material, with sizes ranging between: 20 and 200 nm. The basic composition for both the core and the shell can be changed, providing a wide range of properties and applications (e.g. nanosensors, dyes). “Core-Shell/Hollow” structures are synthesized in two stages: the core is synthesized through conventional polymerization in emulsion and then it is incubated with a secondary emission, containing monomers and initiators, synthesizing the shell. The droplet fusion process and monomer migration determine core occurrence in the second emulsion, on which shells are formed by polymerization. Protein/”Core-Shell/Hollow” and SiO2 nanoparticle structures, with applications in controlled drug release systems are a new trend in biomedicine and a challenge for experts in the field. © SGEM2014.

Sebestyen Z.,Hungarian Academy of Sciences | Czegeny Z.,Hungarian Academy of Sciences | Badea E.,National Research and Development Institute for Textiles and Leather INCDTP | Badea E.,University of Craiova | And 6 more authors.
Journal of Analytical and Applied Pyrolysis | Year: 2015

The aging mechanism of leather and parchment was studied by thermoanalytical methods to understand the effect of the environment on the historical manuscripts and the heritage of libraries and archives. Alkaline and acidic treatments followed by thermal dehydration were applied to achieve chemical changes in the structure of new leather and parchment similar to the slow natural aging of historical samples. Chemical and structural changes during both natural and artificial aging processes were characterized by thermoanalytical techniques. The thermal stability and the evolution profile of the decomposition products under slow heating were studied by thermogravimetry/mass spectrometry (TG/MS). The distribution of the decomposition products of these collagen-based materials under fast pyrolysis was characterized by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). It was found that the maximal rate of the thermal decomposition (DTGmax) significantly decreases by aging in case of both leather and parchment samples indicating the degree of deterioration. Py-GC/MS has been found to be a suitable technique to sensitively monitor the degradation of the polyphenolic components of the vegetable tannins under natural or artificial aging. It was established that the tannin content of leather is more significantly affected by natural aging and alkaline treatment than the main structure of the polypeptide chains. Principal component analysis (PCA) has been used to find statistical correlations between the experimental data for leather samples. The results of the PCA confirmed that the alkaline treatment and the natural aging processes similarly modify the tannin content of the vegetable tanned leather. © 2015 Elsevier B.V. All rights reserved.

Ficai A.,Polytechnic University of Bucharest | Andronescu E.,Polytechnic University of Bucharest | Voicu G.,Polytechnic University of Bucharest | Ghitulica C.,Polytechnic University of Bucharest | And 3 more authors.
Chemical Engineering Journal | Year: 2010

The purpose of this study is the preparation and characterization of highly oriented collagen/hydroxyapatite (COLL/HA) composite materials, through a self-assembling method, starting from collagen gel and hydroxyapatite precursors by an in vitro modified mineralization method. Briefly, this method can be descript as follow: collagen gel (containing 3.21% collagen) is firstly let 24h in contact with Ca(OH)2 suspension in order that Ca2+ neutralize the COOH groups than, in the second stage, the corresponding NaH2PO4 is added, in order to form HA. The synthesis of COLL/HA nanocomposite is performed under controlled experimental conditions: 37°C, pH=9 and air drying. The morphology of the composite material is strongly influenced by the drying method, especially due to the drying time. If the freeze drying method is used the obtained material is highly porous, but no orientation can be observed. In air, the drying is slow enough so that the wet composite material can reorganize and become uniaxial oriented. Our results prove that in certain conditions, oriented COLL/HA nanocomposites materials can be obtained, starting from collagen and hydroxyapatite precursors, through a very simple and accessible method. It is quite difficult to quantify the orientation degree of the composite, but, most of the fibres are uniaxialy oriented, the average orientation degree being 97.46%. The resulted composite materials were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Differential Thermal Analysis coupled with Thermal Gravimetry Analysis (DTA-TG), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). © 2010 Elsevier B.V.

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