TY  - JOUR
A1  - Wagner, Tom
A1  - Lazar, Jaroslav
A1  - Schnakenberg, Uwe
A1  - Böker, Alexander
T1  - In situ Electrothemical Impedance Spectroscopy of Electrostatically Driven Selective Gold Nanoparticle Adsorption on Block Copolymer Lamellae
JF  - Trials
N2  - Electrostatic attraction between charged nano particles and oppositely charged nanopatterned polymeric films enables tailored structuring of functional nanoscopic surfaces. The bottom-up fabrication of organic/inorganic composites for example bears promising potential toward cheap fabrication of catalysts, optical sensors, and the manufacture of miniaturized electric circuitry. However, only little is known about the time-dependent adsorption behavior and the electronic or ionic charge transfer in the film bulk and at interfaces during nanoparticle assembly via electrostatic interactions. In situ electrochemical impedance spectroscopy (EIS) in combination with a microfluidic system for fast and reproducible liquid delivery was thus applied to monitor the selective deposition of negatively charged gold nanoparticles on top of positively charged poly(2-vinylpyridinium) (qP2VP) domains of phase separated lamellar poly(styrene)-block-poly(2-vinylpyridinium) (PS-b-qP2VP) diblock copolymer thin films. The acquired impedance data delivered information with respect to interfacial charge alteration, ionic diffusion, and the charge dependent nanoparticle adsorption kinetics, considering this yet unexplored system. We demonstrate that the selective adsorption of negatively charged gold nanoparticles (AuNPs) on positively charged qP2VP domains of lamellar PS-b-qP2VP thin films can indeed be tracked by EIS. Moreover, we show that the nanoparticle adsorption kinetics and the nanoparticle packing density are functions of the charge density in the qP2VP domains.
KW  - impedance spectroscopy
KW  - block copolymers
KW  - nanoparticles
KW  - electrostatics
KW  - adsorption kinetics
Y1  - 2016
U6  - https://doi.org/10.1021/acsami.6b07708
SN  - 1944-8244
VL  - 8
SP  - 27282
EP  - 27290
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Koshkina, Olga
A1  - Westmeier, Dana
A1  - Lang, Thomas
A1  - Bantz, Christoph
A1  - Hahlbrock, Angelina
A1  - Würth, Christian
A1  - Resch-Genger, Ute
A1  - Braun, Ulrike
A1  - Thiermann, Raphael
A1  - Weise, Christoph
A1  - Eravci, Murat
A1  - Mohr, Benjamin
A1  - Schlaad, Helmut
A1  - Stauber, Roland H.
A1  - Docter, Dominic
A1  - Bertin, Annabelle
A1  - Maskos, Michael
T1  - Tuning the Surface of Nanoparticles: Impact of Poly(2-ethyl-2-oxazoline) on Protein Adsorption in Serum and Cellular Uptake
JF  - Macromolecular bioscience
N2  - Due to the adsorption of biomolecules, the control of the biodistribution of nanoparticles is still one of the major challenges of nanomedicine. Poly(2-ethyl-2-oxazoline) (PEtOx) for surface modification of nanoparticles is applied and both protein adsorption and cellular uptake of PEtOxylated nanoparticles versus nanoparticles coated with poly(ethylene glycol) (PEG) and non-coated positively and negatively charged nanoparticles are compared. Therefore, fluorescent poly(organosiloxane) nanoparticles of 15 nm radius are synthesized, which are used as a scaffold for surface modification in a grafting onto approach. With multi-angle dynamic light scattering, asymmetrical flow field-flow fractionation, gel electrophoresis, and liquid chromatography-mass spectrometry, it is demonstrated that protein adsorption on PEtOxylated nanoparticles is extremely low, similar as on PEGylated nanoparticles. Moreover, quantitative microscopy reveals that PEtOxylation significantly reduces the non-specific cellular uptake, particularly by macrophage-like cells. Collectively, studies demonstrate that PEtOx is a very effective alternative to PEG for stealth modification of the surface of nanoparticles.
KW  - cellular uptake
KW  - nanoparticles
KW  - poly(2-ethyl-2oxazoline)
KW  - poly(ethylene glycol)
KW  - protein adsorption
Y1  - 2016
U6  - https://doi.org/10.1002/mabi.201600074
SN  - 1616-5187
SN  - 1616-5195
VL  - 16
SP  - 1287
EP  - 1300
PB  - Wiley-VCH
CY  - Weinheim
ER  -