Investigation
of Nanostructures using Small-Angle X-ray Scattering
Thünemann A. F.1
1BAM Federal Institute for Materials
Research and Testing, Unter den Eichen
87, 12205 Berlin, Germany
This
talk focuses on (polymeric) nanostructures in the context of using small-angle
X-ray scattering (SAXS) for their analysis. A size range of 1 to 100 nm is
covered. Examples are given for diluted polymeric systems, polymer stabilized core-shell
nanoparticles and silver nanoparticles.
Hyperbranched
poly(ethylene imine)s (PEI)s functionalized with maltose, maltotriose and
maltoheptaose from distinct core-shell globular nanoparticles as revealed using
the Beaucage unified exponential/power-law approach [1].
The functionalized PEIs possess a remarkable stability against changes of pH
and temperature, which makes them promising for a wide range of biomedical
applications. Non-viral gene vectors, based on PEI are discussed such as
thyroid hormone (T3)-modified polyethylene glycol-PEI graft copolymers [2] and
uronic acids functionalized PEIs [3].
The synthesis of peptide-coated silver nanoparticles is explained [4] and
how these particles are used in nanotoxicological studies [5].
Further nanostructures are superparamagnetic core-shell nanoparticles as solid
supports for an advanced peptide synthesis [6] and the fibril structure of eukaryote type actin and profilin [7]. It
is explained how the nanostructures of micrometer-sized cellulose beads can be
revealed without drying in their gnativeh aqueous surroundings [8]. Analytically monitored digestions of silver nanoparticles and their
toxicity for human intestinal cells are reported (see figure below). The
progress of standardization of SAXS as a reliable and traceable method for
nanotechnology will be discussed.
Figure.
Analytics of digested silver nanoparticles after step (2, mouth) with
artificial saliva, gastric juice (3, stomach) and after the complete digestion
process (4, intestines). (a) Filed flow fractionation (A4F) fractograms with
UV/vis detection, (b) DLS and (c) SAXS (Böhmert et.
al. Nanotoxicology doi:10.3109/17435390.2013.815284).
References:
1. Thunemann, A. F.; Bienert, R.; et. al. Macromolecular Chemistry and Physics 2012, 213 (22),
2362-2369.
2. Rudolph,
C.; Sieverling, N.; Schillinger, U.; Thunemann, A. F. et. al. Biomaterials 2007, 28 (10),
1900-1911.
3. Weiss,
S. I.; Sieverling, N.; Niclasen, M.; Thunemann, A. F. et. al. Biomaterials 2006, 27 (10),
2302-2312.
4. Graf,
P.; Mantion, A.; Thunemann, A. F.; Chemistry-a
European Journal 2009, 15 (23), 5831-5844.
6. Stutz,
C.; Bilecka, I.; Thunemann, A. F.; et. al. Chemical communications
2012, 48 (57), 7176-8.