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The association of magnetic nanoparticles, which could be controlled by a magnetic field and have dimensions which facilitate their penetration in cells/tissues, with hydrogel type biopolymeric shells confer them compatibility and the capacity to retain and deliver bioactive substances. The main objective of this work is the development of a new system based on a biocompatible polymer with organic-inorganic structure capable of vectoring support for biologic active agents (L: -asparaginase, e.g.). Characterization of size and morphology of the hydrogel-magnetic nanoparticles with entrapped L: -asparaginase was made using Dynamic Light Scattering method, Transmission Electron Microscopy and Confocal Microscopy. The structure of magnetic nanoparticles coated with hydrogel was characterized by Fourier Transformed Infrared Spectroscopy. The cytotoxicity of nanoparticles was evaluated and also the interactions with microorganisms. We obtained hydrogel-magnetic nanoparticles with L: -asparaginase entrapped, with sizes below 30 nm in dried stage, capable to penetrate the cells and tissues.

The aim of our study consisted in obtaining ZnO nanorods using a photonic crystal (PC) structure as substrate. For obtaining of such structures, a PC presenting with electroconductive properties was chosen. Thus, the first step was represented by the synthesis of a copper nanoparticles shell composed by a maximum of seven layers of inorganic particle. This core-shell structure was subsequently used for the generation of ZnO nanorods by electrochemical deposition. The obtained materials were characterized by SEM, dynamic light scattering, UV-Vis, and X-ray powder diffraction analysis. [ABSTRACT FROM AUTHOR]

Nanocomposites of divinylbenzene-maleic anhidride (DVB-MA) copolymers were synthesized in aqueous medium by generating silver nanoparticles from AgNO3-NaBH4 reaction. SEM images evidence the forming of metal nanoparticles on the particles surface of DVB-MA copolymers. The copolymer particles have larger diameters in the presence of monoesther maleic of nonyl phenol ethoxylate or sodium montmorillonite than DVB-MA copolymer particles although the nanoparticles' forming is still possible. The average size and the Zeta potential of the hybrid particles decrease in water, toward the initial copolymers sustains the forming of nanocomposites with Ag nanoparticles on the surface. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles were obtained using an adjusted Massart method and were covered in a layer-by-layer technique with hydrogel-type biocompatible shells, from chitosan and hyaluronic acid. The synthesized nanocomposites were characterized using dynamic light scattering, transmission electron microscopy, and Fourier transformed infrared spectroscopy. Biocompatibility of magnetic nanostructures was determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) cell proliferation assay, swelling tests, and degradation tests. In addition, interaction of hydrogel-magnetic nanoparticles with microorganisms was studied. The possibility of precise nanoparticles size control, as long as the availability of bio-compatible covering, makes them suitable for biomedical applications. [ABSTRACT FROM AUTHOR]

This research focuses on the synthesis of multi-walled carbon nanotubes (MWCNTs) decorated with TiO2 nanoparticles (NPs) and incorporated in cellulose acetate-collagen film in order to obtain a new biomaterial with potential biomedical applications and improved antimicrobial activity. The successful decoration of the MWCNTs with TiO2 NPs was confirmed by several structural and morphological analysis, such as Fourier transformed infrared spectroscopy, Raman spectroscopy, X-ray diffraction and transmission electron microscopy. The obtained nanocomposites were further incorporated into cellulose acetate-collagen films, at different concentrations and absorption kinetics, antimicrobial activity and in vitro biocompatibility of the obtained films was investigated. The antimicrobial tests sustained that the presence of the nanocomposites into the polymeric matrix is an important aspect in increasing and maintaining the antimicrobial activity of the polymeric wound dressings over time. The biocompatibility and cytotoxicity of the obtained films was evaluated using cellular viability/proliferation assay and fluorescent microscopy which revealed the ability of the obtained materials as potential wound dressing biomaterial. [ABSTRACT FROM AUTHOR]

Cadmium sulfide nanocrystals (quantum dots) have been prepared using polymer solution as template. The new polymer is a vinyl acetate- maleic anhydride (VAcMA) copolymer obtained by using an original procedure developed in our laboratory. The influence of composition and concentration of the polymer on the size and the optical properties of the semiconductor nanoparticles has been studied. The influence of the reaction parameter was also investigated in order to obtain a versatile procedure to prepare nanocrystals with tunable optical properties. The reaction in polymeric matrix could lead to the formation of wide range of particle size (3-8 nm). In addition to modify the emission properties by controlling the particle size, CdS nanocrystals were doped with Zn, Cu and Mn ions. Both blue and red shifts of the maximum emission wavelength were recorded. QD-polymer composites obtained from CdS nanoparticles prepared in VAcMA matrix have been investigated by UV-VIS, fluorescence and IR spectroscopy, TEM and DLS. The photophysical properties of the semiconductor nanoparticles obtained in polymer matrix was compared for different QD-polymer composites, according to the obtaining procedure. [ABSTRACT FROM AUTHOR]

In this study, multi-walled carbon nanotubes (MWCNTs) were decorated with different types of nanoparticles (NPs) in order to obtain hybrid materials with improved antimicrobial activity. Structural and morphological analysis, such as Fourier transformed infrared spectroscopy, Raman spectroscopy, X-ray diffraction, transmission electron microscopy, environmental scanning electron microscopy/energy-dispersive X-ray spectroscopy and the Brunauer–Emmett–Teller technique were used in order to investigate the decoration of the nanotubes with NPs. Analysis of the decorated nanotubes showed a narrow size distribution of NPs, 7–13 nm for the nanotubes decorated with zinc oxide (ZnO) NPs, 15–33 nm for the nanotubes decorated with silver (Ag) NPs and 20–35 nm for the nanotubes decorated with hydroxyapatite (HAp) NPs, respectively. The dispersion in water of the obtained nanomaterials was improved for all the decorated MWCNTs, as revealed by the relative absorbance variation in time of the water-dispersed nanomaterials. The obtained nanomaterials showed a good antimicrobial activity; however, the presence of the NPs on the surface of MWCNTs improved the nanocomposites' activity. The presence of ZnO and Ag nanoparticles enhanced the antimicrobial properties of the material, in clinically relevant microbial strains. Our data proves that such composite nanomaterials are efficient antimicrobial agents, suitable for the therapy of severe infection and biofilms. [ABSTRACT FROM AUTHOR]