Researcher, Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN)
Design and construction of a nanoparticle synthesis station based on the in-liquid electric arc discharge method. Using this method to carry out several experiments related to the synthesis of new types of nanoparticles, the study of the basics synthesis parameters influencing the characteristics of the obtained nanoparticles, creating procedures to obtain, purify and disperse the synthesized nanoparticles for their appropriate characterization and application and to enhance the synthesis method.
Abstract: Graphene is currently investigated as a promising membrane material in which selective pores can be created depending on the requirements of the application. However, to handle large-area nanoporous graphene a stable support material is needed. Here, we report on composite membranes consisting of large-area single layer nanoporous graphene supported by a porous polymer. The fabrication is based on ion-track nanotechnology with swift heavy ions directly creating atomic pores in the graphene lattice and damaged tracks in the polymer support. Subsequent chemical etching converts the latent ion tracks in the supporting polymer foil, here polyethylene terephthalate (PET), into open microchannels while the perfectly aligned pores in the graphene top layer remain unaffected. To avoid unintentional damage creation and delamination of the graphene layer from the substrate, the graphene is encapsulated by a protecting poly(methyl methacrylate) (PMMA) layer. By this procedure a stable composite membrane is obtained consisting of nanoporous graphene (coverage close to 100%) suspended across selfaligned track-etched microchannels in a polymer support film. Our method presents a facile way to create high quality suspended graphene of tunable pore size supported on a flexible porous polymeric support, thus enabling the development of membranes for fast and selective ultrafiltration separation processes.
Pub.: 14 Jul '17, Pinned: 18 Jul '17
Abstract: Micrometer sized oxidation patterns were created in chemical vapor deposition (CVD) grown graphene through scanning probe lithography (SPL) and then subsequently reduced by irradiation using a focused x-ray beam. Throughout the process, the films were characterized by lateral force microscopy (LFM), micro-Raman (µ-RS) and micro-x-ray photoelectron spectroscopy (µ-XPS). Firstly, the density of grain boundaries was found to be crucial in determining the maximum possible oxygen coverage with SPL. Secondly, the dominate factor in SPL oxidation was found to be the bias voltage. At low voltages, only structural defects are formed on grain boundaries. Above a distinct threshold voltage, oxygen coverage increased rapidly, with the duration of applied voltage affecting the final oxygen coverage. Finally, we found that, independent of initial conditions, types of defects or the amount of SPL oxidation, the same set of empirical coupled rate equations describes the reduction dynamics with the limiting reduction step being C-C→C=C.
Pub.: 18 Jul '17, Pinned: 18 Jul '17
Abstract: Chemotherapy and photothermal therapy can be efficiently integrated to achieve enhanced antitumor efficacy by using carbon nanotubes (CNTs) which are super in delivering drug and converting near infrared radiation (NIR) into heat. We previously developed an innovative TAT-chitosan functionalized MWCNTs (MWCNTs/TC) based drug delivery system for doxorubicin (DOX) and preliminarily investigated its release profile and antitumor effect. In the present study, the application potential of MWCNTs/DOX/TC in chemo-photothermal combination therapy was further explored. The in vitro drug release, photothermal effect, cellular uptake and cytotoxicity were assessed. The in vivo anti-tumor effect of MWCNTs/DOX/TC was further evaluated by noninvasive bioluminescence imaging. It was demonstrated that this innovative drug delivery system not only realized a conspicuously sustained release of DOX, but also retained the optical properties of MWCNTs for a high photothermal effect upon NIR irradiation, and exhibited remarkably enhanced anti-tumor efficacy through the synergistic function of chemotherapy and photothermal ablation.
Pub.: 18 Jul '17, Pinned: 18 Jul '17