Deutsche Tagung f ¨ur Forschung mit ... - SNI-Portal

Biologische Systeme und Medizin Poster: Mi., 14:00–16:30 M-P209
Monitoring the degradation of spherical polymeric nanoparticles with scattering
methods
Thomas Siegemund 1,2 , Bernd-Reiner Paulke 3 , Herbert Schmiedel 1 , Natalie
Bordag 2 , Steffen Lindert 1 , Wolfgang Härtig 2
1 University of Leipzig, Faculty of Physics and Earth Science, Institute of Experimental
Physics I, Soft Matter Physics – 2 Univerity of Leipzig, Paul Flechsig Institut for Brain
Research, Department of Neurochemistry – 3 Fraunhofer Institute for Applied Polymer
Research
For the delivery of drugs, the use of nanoparticles as carriers has been described as
a promising approach. The transport of drugs to a single target and the protection
from premature degradation allows to reduce dosis and side effects. Here, we prepared
nanoparticles as carriers for the model drug thioflavin T that bind Alzheimers disease
related fibrillar amyloid β-peptides (Aβ) in the brain. These polymer colloids are
composed of a polystyrene core and a degradable PBCA [poly(butyl-2-cyanoacrylate)]
shell with a diameter of 90-150 nm as shown by photon correlation spectroscopy.
The enzymatic degradation of core-shell nanoparticles, as required in vivo, was shown
after their treatment with porcine liver esterase, a non-specific esterase, and basic/acidic
hydrolysis in vitro. Shells of nanoparticles were dose-dependently degraded while their
polystyrene cores remained intact. Furthermore, we found a simple method with a satisfying
accuracy for the determination of particle diameters based on their wavelengthdependent
absorption. Additionally, we applied static and dynamic light scattering as
useful tools to monitor the particle diameters during enzymatic degradation.
Furthermore, we compare and verify our results by using small-angle neutron scattering.
We measured the degradation-dependent changes in the neutron scattering density
profile at the facilities of IBR-2 (Dubna, Russia) and BNC (Budapest, Hungary).
This study was supported by the BMBF, grant 03DU03LE.
Fig. 1: Time-dependent
degradation of HL-52 (core:
perdeuterated polystyrene,
shell: PBCA) in water and
water:deuterium oxide (1:4)
SANS measurement at the
detector “Yellow Submarine”
(BNC, Budapest)