Day 3 :
Leibniz University Hannover, Germany
Time : 09:30 - 10:00
H Jörg Osten has studied Physics in Poland. First he was working at the Institute for Physical Chemistry in Berlin in the field of Radio-Frequency Spectroscopy. In 1988, he joined the Institute of Semiconductor Physics (IHP) in Frankfurt, Germany. In 2002, he became the Director of the Institute Electronic Materials and Devices at the Leibniz University of Hannover, Germany, where he also holds a Chair for Electronic Materials and Technology. He has published more than 270 papers and gave more than 80 invited and 200 contributed talks at international conferences.
The ability to integrate crystalline metal oxide dielectric layers into silicon structures can open the way for a variety of novel applications which enhances the functionality and flexibility ranging from high-K replacements in future MOS devices to oxide/silicon/oxide heterostructures for nanoelectronic application in quantum-effect devices. We present results for crystalline gadolinium oxides on silicon grown by solid source molecular beam epitaxy. The dielectric properties of such oxides are sensitive to small variations in structure and symmetry. It is known that thin layers of crystalline rare earth oxides can exhibit significant larger dielectric constants compared to bulk materials. We will explain these effects by strain induced structural phase deformations. First, we will report on the dependence of the dielectric constant on layer thickness for epitaxial Gd2O3 on Si (111). Controlling the oxide composition in ternary (Gd1-xNdx)2O3 thin films enables us to tune the lattice mismatch to silicon, and thus the strain-induced variation in the dielectric constants of the layer. We will finally demonstrate different approaches to grow Si nanostructures embedded into crystalline rare earth oxides. By efficiently exploiting the growth kinetics one could create nanostructures exhibiting various dimensions, ranging from three dimensionally confined quantum dots to the quantum wells, where the particles are confined in one of the dimensions. Double-barrier structures comprising epitaxial insulator as barriers and Si as quantum-well are attractive candidate for resonant tunneling devices. Embedded Si quantum dots exhibit excellent charge storage capacity with competent retention and endurance characteristics suitable for non-volatile memory device applications.
Aquatic Contaminants Research Division, Canada
Time : 10:00 - 10:30
Christian Gagnon is a Senior Researcher in Geochemistry at Environment and Climate Change, Canada. He obtained his PhD from the University of Quebec/INRS-Oceanography and completed his Postdoctoral studies on the bioavailability of contaminants at the State University of New York, Stony Brook. His research focuses on the fate, transformation and behaviour of chemical contaminants released into the aquatic environment. All of its work aims at a better understanding of the mechanisms of transformation and the fate of metals and emerging substances in waste water discharges and the receiving environment. He has published over 150 scientific publications and reports and has contributed to over 250 scientific presentations on contaminant behaviour in the aquatic environment.
Silver nanoparticle is largely used for various products and is finally found in discharged wastewaters. Silver was typically detected in all investigated municipal wastewaters. Concentrations of total silver in municipal were measured to assess Ag removal efficiency of treatment plants. Wastewater samples were also analyzed by the technique of single-particle inductively coupled plasma–mass spectrometry (SP-ICP-MS) to identify and determine that they contained silver nanoparticles. Nano-sized forms would account for less than 5% of the total Ag released from municipal effluents. Once released in the receiving environment, Ag NPs can undergo major transformation and their initial properties can be modified under natural conditions. The developed analytical approach was used for tracking silver nanoparticles and their degradation products over a period of 80 days. Particle size distributions changed significantly under different experimental conditions where most material was found in coarse colloidal fractions (<100 kDa). The presence of natural humic substances slowed degradation of nanoparticles, which is characterized by the increase of free/small ion complexes and the detection of colloids with a size less than 80 nm. Haft-live values were generally estimated to be less than 15 days under natural conditions. Future research on nanotoxicity should consider exposure conditions, and then potential transformation, for risk assessment studies.
University of South Australia, Australia
In this talk, author will present recent developments from his lab on various biomaterial coatings that are facilitated by plasma deposition. These include antibacterial coatings, drug release platforms and cell guidance/capture surfaces. Undesired bacterial adhesion and subsequent colonization of medical devices is a substantial medical problem causing complex and sometime fatal infections. We have developed various strategies for generation of antibacterial coatings that can be applied to medical device surfaces. These involve means such as silver nanoparticles, antibiotics, nitric oxide, quaternary ammonium compounds (QACs) or simply coatings that have intrinsic low fouling properties. All these coatings are facilitated by plasma deposition, a technique that provides functional films placed to the surface of any type of material. Important for applications, we not only extensively test our coating for their antibacterial efficacy against medically relevant pathogens but also assess their potential cytotoxicity to mammalian cell and inflammatory consequences. We have also developed methods for the synthesis and surface immobilization of hybrid antibacterial nanocapsules and nanoparticles, including such capable of triggered release. In a second part of the talk author outline his work on developing advanced nanoengineered plasma polymer coatings capable of directing cellular behavior including adhesion, proliferation, differentiation and migration. We have developed unique capabilities to control and tailor entire spectrum of surface properties such as chemistry, wettability, ligand densities, nanomechanics and nanotopography in a substrate independent fashion. We can tailor all these surface properties in a gradient manner too. Author will demonstrate how we use surface gradients of nanoparticles density to study the influence of surface nanotopography on the behavior of various cell types, including immune cells and author will outline how we guide the differentiation of stem cells by tailoring surface chemistry, nanotopography or density of signaling molecules. Author will briefly present drug delivery and release platforms that we have developed including a method for solvent free encapsulation of drug particles. A recently developed device for selective cancer cell capture for complex liquids and how it is used for diagnostic of bladder cancer will also be presented.