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"VIEM", les Vendredis de l’IEM

Salle de conférence

vendredi 26 septembre 2014, à 9h15

Professeur Jae-Min OH

Professeur Yonsei University - South Korea

Biological applications of layered nanomaterials depending on physico-chemical properties

Nano-Bio Materials Laboratory (NBML), Department of Chemistry and Medical Chemistry, College of Science and Technology, Yonsei University, Wonju, Gangwondo 220-710, Korea

Recently, there are increasing interests on nanomaterials in bio-medical applications such as drug delivery, therapeutics, diagnostics and etc. Among the various types nanomaterials, two dimensional layered nanostructures which is also known as layered double hydroxide (LDH), is attracting tremendous interests as potential candidate for drug delivery nanocarrier. LDHs are composed of mixed metal hydroxide layers with the possibility of various compositions and they contain exchangeable anions in interlayer nanospace. Intercalation of bioactive anionic molecules such as genes, vitamins and anticancer drugs into LDHs could enhance the chemical stability, biological inertness and bioavailability of bioactive molecules. We successfully enhanced drug efficacy of anticancer drugs, methotrexate (MTX) and 5-fluorouracil (5-Fu), by introducing them into LDH interlayers, in terms of cellular uptake, controlled release, drug resistance bypassing and etc. The particle size of LDH nanomaterials could be easily controlled from tens of nanometers to a few hundred nanometers, which was determined to affect cellular uptake efficiency as to cancer cells. Surface functionalization of LDH nanomaterials with cellular targeting moiety is also possible to realize target-specific drug delivery system. Furthermore, we found that the LDH nanomaterials are highly compatible to not only various cell culture lines but also human blood cells and plasma proteins compared with various nano drug delivery system such as carbon nanotube, gold and iron oxide nanoparticles.

vendredi 26 septembre 2014, à 10h00

Docteur Alexander SACHSE

Institute of Chemistry - Brazil

Design of hierarchical porous materials for catalytic applications. Monoliths as flow-through microreactors and mesoporous zeolites

Hierarchical porous materials have attracted a great deal of attention during the last decade. This increasing interest is particularly due to their prospective applications such as energy storage and conversion, liberation of active principles and catalysis. These materials are ideally composed of interconnected porosity at various length scales. Additionally, the development of strategies permitting to simplify the implementation of heterogeneous catalysis is one of the major issues in materials science. Recently there has been a trend towards flow catalysis. This has several advantages most importantly process intensification. The first part of this talk will cover the development of functional hierarchical meso- and macroporous silica monoliths employed as catalytic microreactors for flow-through applications. Special interest will be given to the synthesis of hierarchical porous silica monoliths based on spinodal decomposition, their functionalization and their application as flow microreactors. In particular various strategies of functionalization, such as grafting with organic and inorganic functions and in-situ synthesis of nanoparticles will be presented. Such mircoreactors permit to achieve significantly higher conversions and productivities in catalysis compared to experiments carried out in batch or packed-bed reactors. A synthetic strategy will be presented, referred as pseudomorphic transformation, which allows for the transformation of the amorphous silica skeleton of the monolith into zeolite phases. In this way microreactors based on SOD and LTA phase comprising flow-through macropores could be disclosed. These monoliths show interesting results when used as microreactors for catalytic applications and when employed for the removal of bivalent cations from effluents in flow. The second part of the communication will treat about the use of chitin as renewable bio-template for the formation of mesoporous materials. By combining the self-assembly properties of chitin nanorods with the sol gel process materials with new textural properties could be disclosed. This will be highlighted for the case of silica titania mixed oxides and alumina. This technique allows for the tunability of textural properties achieving materials with high activity in catalysis. The last part of this communication will deal with the quest for the achievement of hierarchical meso- and microporous zeolites which is in the center of the attention in materials synthesis due to the possibility of enhancing mass transfer properties when compared to classical microporous zeolites. A bottom-up and a top-down strategy allowing for the obtention of such hierarchical structures will be presented by the employment of a new class of tempting molecules.



L’I.E.M. organise des séminaires internes/externes les "Vendredis de l’IEM" qui ont lieu chaque vendredi de 9h30 à 11h15 dans la salle de conférence.

L’esprit de ces séminaires est de "causer la science". Il peut être présenté des résultats exceptionnels mais aussi des "résultats problèmes ou négatifs" avec l’espoir que les discussions pourront apporter des solutions.