TY  - JOUR
A1  - Stanglmair, Christoph
A1  - Neubrech, Frank
A1  - Pacholski, Claudia
T1  - Chemical routes to surface enhanced infrared absorption (SEIRA) substrates
JF  - Zeitschrift für physikalische Chemie : international journal of research in physical chemistry and chemical physics
N2  - Bottom-up strategies for fabricating SEIRA substrates are presented. For this purpose, wet-chemically prepared gold nanoparticles are coated with a polystyrene shell and subsequently self-assembled into different nanostructures such as quasi-hexagonally ordered gold nanoparticle monolayers, double layers, and honeycomb structures. Furthermore elongated gold nanostructures are obtained by sintering of gold nanoparticle double layers. The optical properties of these different gold nanostructures are directly connected to their morphology and geometrical arrangement - leading to surface plasmon resonances from the visible to the infrared wavelength range. Finally, SEIRA enhancement factors are determined. Gold nanoparticle double layers show the best performance as SEIRA substrates.
KW  - bottom-up
KW  - gold nanoparticles
KW  - self-assembly
KW  - surface enhanced spectroscopy
Y1  - 2018
U6  - https://doi.org/10.1515/zpch-2018-1132
SN  - 0942-9352
VL  - 232
IS  - 9-11
SP  - 1527
EP  - 1539
PB  - De Gruyter
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Fallah, Mohammad A.
A1  - Stanglmair, Christoph
A1  - Pacholski, Claudia
A1  - Hauser, Karin
T1  - Devising Self-Assembled-Monolayers for Surface-Enhanced Infrared Spectroscopy of pH-Driven Poly-L-lysine Conformational Changes
JF  - Langmuir
N2  - Surface-enhanced infrared absorption spectroscopy (SEIRA) is applied to study protein conformational changes. In general, the appropriate functionalization of metal surfaces with biomolecules remains a challenge if the conformation and activity of the biomolecule shall be preserved. Here we present a SEIRA study to monitor pH-induced conformational changes of poly-L lysine (PLL) covalently bound to a thin gold layer via self assembled monolayers (SAMs). We demonstrate that the composition of the SAM is crucial. A SAM of 11-mercaptoundecanonic acid (MUA) can link PLL to the gold layer, but pH-driven conformational transitions were hindered compared to poly-L lysine in solution. To address this problem, we devised a variety of SAMs, i.e., mixed SAMs of MUA with either octanethiol (OT) or 11-mercapto-1-undecanol (MUoL) and furthermore SAMs of MT(PEG)(4) and NHS-PEG(10k)-SH. These mixed SAMs modify the surface properties by changing the polarity and the morphology of the surface present to nearby PLL molecules. Our experiments reveal that mixed SAMs of MUA-MUoL and SAMs of NHS-PEG(10k)-SH-MT(PEG)(4) are suitable to monitor pH-driven conformational changes of immobilized PLL. These SAMs might be applicable for chemoselective protein immobilization in general.
Y1  - 2016
U6  - https://doi.org/10.1021/acs.langmuir.6b01742
SN  - 0743-7463
VL  - 32
SP  - 7356
EP  - 7364
PB  - American Chemical Society
CY  - Washington
ER  -