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In this study, the filler–matrix interactions are assessed in two nanocomposites having different antibacterial activity. The two polymers used as matrix are poly(amide) 6 (PA6) and low-density poly(ethylene) (LDPE). The filler, zinc oxide (ZnO) nanoparticles, with a content as low as 1 w/w% in the polymers showed great antibacterial activity against Escherichia coli and Staphylococcusaureus. However, the bacterial slaying capability of composites was found better when ZnO was dispersed in PA6, where the efficiency is similar to pure ZnO particles. The dispersion of ZnO and its interactions with the matrix have been investigated by means of scanning electron microscope, rheology, thermogravimetric analysis and differential scanning calorimeter. This study shows stronger interactions of ZnO particles with LDPE, which could have an effect on final antibacterial properties. [ABSTRACT FROM AUTHOR]

The setup of colloidal hybrid nanosystems based on biomimetic calcium phosphate apatites doped with europium ions has recently raised great interest in the pharmacological community, especially due to their bio-inspired character. This is especially relevant in relation with medical imaging for cancer diagnosis. Questions however remain in relation to a number of applicability aspects, some of which have been examined in this contribution. In a first part of this work, we explored further the luminescence properties of such colloidal nanoparticles. We pointed out, upon excitation of europium, the existence of some non-radiative de-excitation via the vibration of O-H oscillators located at the vicinity of the Eu3+ luminescent centers. The replacement of Eu3+ by Tb3+ ions, less prone to non-radiative de-excitation, was then tested in a preliminary way and can be seen as a promising alternative. In a second part of this work, we inspected the possibility to store these colloids in a dry state while retaining a re-suspension ability preserving the nanometer size of the initial nanoparticles, and we propose a functional protocol involving the addition of glucose prior to freeze-drying. We finally showed for the first time, based on titrations of intracellular Ca2+ and Eu3+ ions, that folic acid-functionalized biomimetic apatite nanoparticles were able to target cancer cells that overexpress folate receptors on their membrane, which we point out here in the case of T-47-D breast carcinoma cells, as opposed to ZR-75-1 cells that do not express folate receptors. This contribution thus opens new exciting perspectives in the field of targeted cancer diagnosis, thus confirming the promise of biomimetic apatites-based colloidal formulations. [ABSTRACT FROM PUBLISHER]

The antimicrobial activity against E. coli, St. aureus and A. niger of zinc oxide when blended with polymers has been measured by an applied dynamic method. Two polymers: poly(amide) 6 (PA6) and low density poly(ethylene) (LDPE) have been used as matrix. ZnO nanoparticles content as low as 1% w/w in the polymers showed great antibacterial activity but no antifungal activity. The results of bacterial slaying capability of these nanocomposites was also found to be better when zinc oxide was dispersed in PA6, where the efficiency is similar to pure ZnO particles. The composites have been investigated by means of scanning electron microscope (SEM) and differential scanning calorimeter (DSC). [ABSTRACT FROM AUTHOR]

A new support for traditional radiotherapy based on the UV emission from Pr 3+ doped LaPO 4 nanoparticles is proposed. This system was obtained by spray pyrolysis methodology. X-ray diffraction (XRD) analysis showed that the synthesized particles exhibited a lanthanum orthophosphate structure. Transmission electron microscopy (TEM) revealed that the ultrasound treatment successfully converted the microparticles into nanoparticles. The surfaces were chemically modified with amino acid (asparagine and aminocaproic acid). XEOL measurements evidenced a broad band in the UVC range, which could allow for application of the system as UVC emitter in internal phototherapy. [ABSTRACT FROM AUTHOR]

Abstract: Hydrated bacterial cellulose (BC) membranes obtained from cultures of Acetobacter xylinum were used in the preparation of silver nanoparticles containing cellulose membranes. In situ preparation of Ag nanoparticles was achieved from the hydrolytic decomposition of silver triethanolamine (TEA) complexes. Scanning electron microscopy (SEM) images and X-ray diffraction (XRD) patterns both lead to the observation of spherical metallic silver particles with mean diameter of 8 nm well adsorbed onto the BC fibriles. [Copyright &y& Elsevier]