@article{StanglmairNeubrechPacholski2018,
  author    = {Stanglmair, Christoph and Neubrech, Frank and Pacholski, Claudia},
  title     = {Chemical routes to surface enhanced infrared absorption (SEIRA) substrates},
  series = {Zeitschrift f{\"u}r physikalische Chemie : international journal of research in physical chemistry and chemical physics},
  volume    = {232},
  journal   = {Zeitschrift f{\"u}r physikalische Chemie : international journal of research in physical chemistry and chemical physics},
  number    = {9-11},
  publisher = {De Gruyter},
  address   = {Berlin},
  issn      = {0942-9352},
  doi       = {10.1515/zpch-2018-1132},
  pages     = {1527 -- 1539},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@article{SemenyshynHentschelStanglmairetal.2018,
  author    = {Semenyshyn, Rostyslav and Hentschel, Mario and Stanglmair, Christoph and Teutsch, Tanja and Tarin, Cristina and Pacholski, Claudia and Giessen, Harald and Neubrech, Frank},
  title     = {In vitro monitoring conformational changes of polypeptide monolayers using infrared plasmonic nanoantennas},
  series = {Nano letters : a journal dedicated to nanoscience and nanotechnology},
  volume    = {19},
  journal   = {Nano letters : a journal dedicated to nanoscience and nanotechnology},
  number    = {1},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1530-6984},
  doi       = {10.1021/acs.nanolett.8b02372},
  pages     = {1 -- 7},
  year      = {2018},
  abstract  = {Proteins and peptides play a predominant role in biochemical reactions of living cells. In these complex environments, not only the constitution of the molecules but also their three-dimensional configuration defines their functionality. This so-called secondary structure of proteins is crucial for understanding their function in living matter. Misfolding, for example, is suspected as the cause of neurodegenerative diseases such as Alzheimer's and Parkinson's disease. Ultimately, it is necessary to study a single protein and its folding dynamics. Here, we report a first step in this direction, namely ultrasensitive detection and discrimination of in vitro polypeptide folding and unfolding processes using resonant plasmonic nanoantennas for surface-enhanced vibrational spectroscopy. We utilize poly-l-lysine as a model system which has been functionalized on the gold surface. By in vitro infrared spectroscopy of a single molecular monolayer at the amide I vibrations we directly monitor the reversible conformational changes between α-helix and β-sheet states induced by controlled external chemical stimuli. Our scheme in combination with advanced positioning of the peptides and proteins and more brilliant light sources is highly promising for ultrasensitive in vitro studies down to the single protein level.},
  language  = {en}
}
@article{FallahStanglmairPacholskietal.2016,
  author    = {Fallah, Mohammad A. and Stanglmair, Christoph and Pacholski, Claudia and Hauser, Karin},
  title     = {Devising Self-Assembled-Monolayers for Surface-Enhanced Infrared Spectroscopy of pH-Driven Poly-L-lysine Conformational Changes},
  series = {Langmuir},
  volume    = {32},
  journal   = {Langmuir},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0743-7463},
  doi       = {10.1021/acs.langmuir.6b01742},
  pages     = {7356 -- 7364},
  year      = {2016},
  abstract  = {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.},
  language  = {en}
}