Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-18233 Zeitschriftenartikel Eichelbaum, M.; Kneipp, Janina; Schmidt, B.E.; Panne, Ulrich; Rademann, K. SERS and Multiphoton-Induced Luminescence of Gold Micro- and Nanostructures Fabricated by NIR Femtosecond-Laser Irradiation Weinheim Wiley-VCH Verl. 2008 ChemPhysChem : a European journal of chemical physics and physical chemistry 9 15 2163 2167 10.1002/cphc.200800417 2016-02-19 OPUS4-18234 Zeitschriftenartikel Schulte, Franziska; Lingott, J.; Panne, Ulrich; Kneipp, Janina Chemical characterization and classification of Pollen We report on the in situ characterization of tree pollen molecular composition based on Raman spectroscopy. Different from purification-based analysis, the nondestructive approach allows (i) to analyze various classes of molecules simultaneously at microscopic resolution and (ii) to acquire fingerprint-like chemical information that was used for the classification of pollen from different species. Hierarchical cluster analysis of spectra from fresh pollen samples of 15 species partly related at the genus level and family level indicates separation of species based on the complete Raman spectral signature and yields classification in accord with biological systematics. The results have implications for the further elucidation of pollen biochemistry and also for the development of chemistry-based online pollen identification methods. Washington, DC American Chemical Society 2008 Analytical chemistry 1 12 10.1021/ac801791a 2016-02-19 OPUS4-18231 Zeitschriftenartikel Kneipp, Janina; Li, X.; Sherwood, M.; Panne, Ulrich; Kneipp, H.; Stockman, M.I.; Kneipp, K. Gold Nanolenses Generated by Laser Ablation-Efficient Enhancing Structure for Surface Enhanced Raman Scattering Analytics and Sensing Nanoaggregates formed by metal spheres of different radii and interparticle distances represent finite, deterministic, self-similar systems that efficiently concentrate optical fields and act as “nanolenses”. Here we verify experimentally the theoretical concept of nanolenses and explore their potential as enhancing nanostructures in surface enhanced Raman scattering (SERS). Self-similar structures formed by gold nanospheres of different sizes are generated by laser ablation from solid gold into water. These nanolenses exhibit SERS enhancement factors on the order of 109. The “chemically clean” preparation process provides several advantages over chemically prepared nanoaggregates and makes the stable and biocompatible gold nanolenses potent enhancing structures for various analytical and sensing applications. Washington, DC American Chemical Society 2008 Analytical chemistry 80 11 4247 4251 10.1021/ac8002215 2016-02-19 OPUS4-20260 Zeitschriftenartikel Schulte, Franziska; Mäder, J.; Kroh, L.W.; Panne, Ulrich; Kneipp, Janina Characterization of pollen carotenoids with in situ and high-performance thin-layer chromatography supported resonant Raman spectroscopy Raman signatures of the carotenoid component are studied in individual pollen grains from different species of trees. The information is obtained as differences in the strong pre-resonant Raman spectra measured before and after photodepletion of the carotenoid molecules. The results provide the first in situ evidence of interspecies differences in pollen carotenoid content, structure, and/or assembly between plant species without prior purification. The analysis of carotenoids in situ is confirmed by high-performance thin-layer chromatography (HPTLC)-supported resonance Raman data measured directly on the HPTLC plates after separation of carotenoids in pollen extracts. Utilization of the in situ, extraction-free procedure in carotenoid analysis will improve sensitivity and structural selectivity and provides insight into carotenoid structure and composition in single pollen grains. Washington, DC American Chemical Society 2009 Analytical chemistry 81 20 8426 8433 10.1021/ac901389p 2016-02-19 OPUS4-23211 Zeitschriftenartikel Schulte, Franziska; Panne, Ulrich; Kneipp, Janina Molecular changes during pollen germination can be monitored by Raman microspectroscopy The processes associated with pollen germination were studied in vitro for two tree species, Salix caprea and Fraxinus excelsior under different nutrient conditions. The results provide evidence of changes in chemical composition of the pollen grains during germination. From the comparison of spectra of the pollen grain body and the growing pollen tube, it can be concluded that there are major chemical differences between these two morphological units. Comparison of germinated and ungerminated pollen grains reveals alterations in the metabolism. Composition of the germinating pollen grain and its morphological units depends on the plant species, but also on the nutrient conditions. The results suggest species-specific utilization of metabolite storage, and potential alterations of the pollen outer coat. Furthermore, discharge of molecules into the nutrient medium may depend on the nutrient conditions in the germination experiments. This has implications for further experiments on dynamic processes in pollen and related plant materials. Weinheim Wiley-VCH Verl. 2010 Journal of biophotonics 3 8-9 542 547 10.1002/jbio.201000031 2016-02-19 OPUS4-21396 Zeitschriftenartikel Klimakow, Maria; Leiterer, Jork; Kneipp, Janina; Rössler, E.; Panne, Ulrich; Rademann, K.; Emmerling, Franziska Combined synchrotron XRD/Raman measurements: In situ identification of polymorphic transitions during crystallization processes A combination of two analytical methods, time-resolved X-ray diffraction (XRD) and Raman spectroscopy, is presented as a novel tool for crystallization studies. An acoustic levitator was employed as sample environment. This setup enables the acquisition of XRD and Raman data in situ simultaneously within a 20 s period and hence permits investigation of polymorphic phase transitions during the crystallization process in different solvents (methanol, ethanol, acetone, dichloromethane, acetonitrile). These real time measurements allow the determination of the phase content from the onset of the first crystalline molecular assemblies to the stable system. To evaluate the capability of this approach, the setup was applied to elucidate the crystallization process of the polymorphic compound nifedipine. The results indicate the existence of solvent-dependent transient phases during the crystallization process. The quality of the data allowed the assignment of the lattice constants of the hitherto unknown crystal structure of the β-polymorph. Washington, DC American Chemical Society 2010 Langmuir 26 13 11233 11237 10.1021/la100540q 2016-02-19 OPUS4-24964 Zeitschriftenartikel Giesen, Charlotte; Müller, Larissa; Mairinger, T.; Drescher, Daniela; Kneipp, Janina; Roos, P.H.; Panne, Ulrich; Jakubowski, Norbert Iodine as an elemental marker for imaging of single cells and tissue sections by laser ablation inductively coupled plasma mass spectrometry A new laser ablation (LA)-ICP-MS method for single cell and cell nucleus imaging was developed. Therein, iodine was employed as an elemental dye for fibroblast cells and for thin tissue sections. At an incubation time of 60 s, iodine is located mainly within the cell nuclei. This effect was illustrated in fibroblast cells, and iodine signal within the cell nucleus was as high as 5 × 104 cps at 4 µm laser spot size. The surrounding cytoplasm was iodinated as well, but to a lesser extent. The spatial resolution attained was sufficient to detect even smaller cell nuclei within a liver biopsy tissue. Furthermore, iodine was successfully employed for biomolecule labeling and we demonstrated that iodine signal increased with increasing thickness of a palatine tonsil tissue. Thus, the use of iodine as an internal standard to correct for tissue inhomogeneities in LA-ICP-MS was investigated for the simultaneous detection of two tumor markers (Her 2 and CK 7) in breast cancer tissue. Additionally, lanthanide background resulting from glass ablation can be corrected for by Eu standardization. London Royal Society of Chemistry 2011 Journal of analytical atomic spectrometry 26 11 2160 2165 10.1039/c1ja10227c 2016-02-19 OPUS4-23482 Zeitschriftenartikel Merk, Virginia; Schulte, Franziska; Rooch, Heidemarie; Feldmann, Ines; Dörfel, Ilona; Österle, Werner; Panne, Ulrich; Kneipp, Janina Surface-enhanced Raman scattering with silver nanostructures generated in situ in a sporopollenin biopolymer matrix Silver nanoparticles were generated based on citrate reduction in the ultrastructure of the sporopollenin biopolymer of Ambrosia artemisiifolia (ragweed) and Secale cereale (rye). The nanoparticles enable the acquisition of SERS spectra and thereby a vibrational characterization of the local molecular structure of sporopollenin. Cambridge Royal Society of Chemistry Chemical Society 2011 Chemical communications 47 11 3236 3238 10.1039/c0cc05326k 2016-02-19 OPUS4-25648 Zeitschriftenartikel Krause, Benjamin Christoph; Seifert, Stephan; Panne, Ulrich; Kneipp, Janina; Weidner, Steffen Matrix-assisted laser desorption/ionization mass spectrometric investigation of pollen and their classification by multivariate statistics RATIONALE A fast and reliable online identification of pollen is not yet available. The identification of pollen is based mainly on the evaluation of morphological data obtained by microscopic methods. METHODS Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) was applied to the analysis of extracts and milled pollen samples. The obtained MALDI data were explored for characteristic peak patterns which could be subjected to a multivariate statistical analysis. RESULTS Two sample preparation methods are presented, which require only minimal or no chemical extraction of the pollen. MALDI pollen spectra could be recorded showing various peak patterns. A multivariate statistics approach allowed the classification of pollen into clusters indicating similarities and differences between various species. CONCLUSIONS These results demonstrate the potential and the reliability of MALDI-TOF MS for the identification and, in combination with multivariate statistics, also for the classification of pollen. Chichester Wiley 2012 Rapid communications in mass spectrometry 26 9 1032 1038 10.1002/rcm.6202 2016-02-19 OPUS4-25742 Zeitschriftenartikel Schenk, Jonas; Batzdorf, Lisa; Emmerling, Franziska; Kneipp, Janina; Panne, Ulrich; Buurman, Merwe Simultaneous UV/Vis spectroscopy and surface enhanced raman scattering of nanoparticle formation and aggregation in levitated droplets The formation and growth of hydroxylamine reduced silver nanoparticles were investigated by simultaneous Raman and UV/Vis spectroscopy coupled to an acoustic levitator as a sample holder. Based on the UV/Vis spectra, a two step particle formation mechanism with fast initial formation and adjacent coalescence can be proposed for the reduction of silver nitrate with hydroxylamine. The presence of the analyte adenine during particle formation resulted in differences in the adenine SERS signature compared to experiments, where adenine was added after particle synthesis. It was possible to monitor the adenine and sodium chloride induced aggregation of the nanoparticles and its dynamics based on both the extinction spectra and the SERS data. Correlating the information from the extinction spectra with the SERS intensity, the maximum SERS signals were observed at maximum extinction of the aggregated nanoparticle solution at the Raman excitation wavelength. Cambridge RSC Publ. Royal Society of Chemistry 2012 Analytical methods 4 5 1252 1258 10.1039/c2ay05744a 2016-02-19