4th EucheMs chemistry congress

Monday, 27-Aug 2012
s730
chem. Listy 106, s587–s1425 (2012)
Nanochemistry / Nanotechnology / Molecular machines, Carbon tubes, sheets, balls
Nanochemistry, nanotechnology and nanostructured
materials – i
o - 0 6 4
Mixed AeroGeLS froM MetAL And
SeMiConduCtor nAnoPArtiCLeS
t. hendeL 1 , L. Kühn 2 , v. LeSnyAK 2 ,
A. K. herrMAnn 2 , n. GAPoniK 2 , A. eyChMüLLer 2
1 Humboldt-Universität zu Berlin, Institut für Chemie, Berlin,
Germany
2 Technische Universität Dresden, Institut für Physikalische und
Elektrochemie, Dresden, Germany
Self-assembled structures are currently of great interest for
nanochemistry and chemical nanotechnology. Aerogels consisting
of nanoparticles combine promising advantages like high porosity,
low density and huge internal surface, whilst retaining the unique
properties of their building blocks like quantum-confined optics
and catalytic behavior.
Following the recent success in fabrication of new types of
aerogels from semiconductor and noble metal nanocrystals, we
demonstrate the water-based formation of mixed aerogels
consisting of strong emitting, thiol-capped CdTe nanoparticles
and thiol-functionalized gold seeds. The formation is carried out
by photochemical treatment and supercritical drying resulting in
homogeneous and voluminous monoliths.
The composition and topography of the gel was examined
by SEM/EDX and TEM proving the highly porous architecture
and the control of particle ratios in the network through the initial
colloid mixtures. Optical behavior was studied by diffuse
reflection and fluorescence spectroscopy verifying the retained
optical properties. With increasing metal ratio the fluorescence
intensity is decreased due to the quenching of the metallic system
on the fluorescence process. By carrying out lifetime
measurements of the produced gels this effect was examined.
Porosity measurements by nitrogen adsorption characterized the
highly porous gel network with specific internal surfaces of
170 m2 /g which is in good accordance to porosity values of such
structures found earlier.
The formation of those gels provides a controllable method
to produce highly porous hybrid materials of special interest for
applications in nanoplasmonic devices and photocatalysis
Keywords: nanoparticles; sol-gel processes; mesoporous
materials; photooxidation; heterogeneous catalysis;
4 th EucheMs chemistry congress
Nanochemistry, nanotechnology and nanostructured
materials – ii
o - 0 6 5
three-diMenSionAL dnA nAnoStruCtureS for
BioLoGiCAL And MAteriALS APPLiCAtionS
h. SLeiMAn 1 , C. MCLAuGhLin 1 , J. fAKhoury 1 ,
G. hAMBLin 1 , K. BuJoLd 1 , C. SerPeLL 1
1 McGill University, Department of Chemistry, Montreal
Quebec, Canada
Three-dimensional structures made of DNA hold the
potential to encapsulate and release drugs, selectively encage
nanomaterials, regulate the activity of proteins, and assemble
networks for catalysis and biomolecule crystallization. A number
of strategies for DNA construction have been developed, through
weaving together DNA strands into tiles, or stapling a DNA strand
into origami structures. Our group has been examining a different
approach to build DNA nanostructures, in which synthetic
molecules are used to control and modify DNA self-assembly.
We will describe the use of this approach to generate
3D-DNA structures, such as DNA cages and nanotubes, with
deliberate variation of geometry, size, single- and double-stranded
forms, permeability and length. These can be dynamically
switched to different internal volumes, and can be ‘opened’ or
closed with specific DNA strands. The size-selective
encapsulation of gold nanoparticles within these host structures
and the release of this cargo when specific DNA strands are added
will be shown. Moreover, these compact 3D-DNA structures can
travel across the plasma membrane of a number of mammalian
cells, without the aid of any transfection reagents. The molecules
shown here represent a new class of selective cellular probes and
drug delivery tools, and can assist the development of nucleic acid
therapeutic routes. Finally, the use of these cages for the
3D-organization of synthetic polymer chains in their core or
corona will be described.
references:
1. Science, 2008, 321, 1795.
2. Chem. Science, 2012, 3, 1980.
3. J. Am. Chem. Soc., 2012, 134, 4280.
4. J. Am. Chem. Soc. 2012, 134, 2888.
5. J. Am. Chem. Soc., 2010, 132, 10212.
6. Nature Chem. 2010,2, 319.
7. Nature Chem., 2009, 1, 390
8. Nature Nanotech., 2009, 4, 349.
9. J. Am. Chem. Soc., 2007, 13376.
Keywords: DNA Structures; Supramolecular chemistry;
Nanostructures; Drug delivery;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc