TY - JOUR A1 - Mohsin, G. F. A1 - Schmitt, F.-J. A1 - Kanzler, C. A1 - Epping, J. D. A1 - Flemig, Sabine A1 - Hornemann, A. T1 - Structural characterization of melanoidin formed from D-glucose and L-alanine at different temperatures applying FTIR, NMR, EPR, and MALDI-ToF-MS JF - Food Chemistry N2 - The aim of this study was to identify specific chemical bonds and characteristic structures in melanoidins formed from D-glucose and L-alanine between 130 and 200 °C. The results might be used to control the type and amount of melanoidin produced during food processing. For this purpose, complementary techniques, such as FTIR, NMR, EPR, and MALDI-ToF, were employed. At 160 °C color, solubility and UV/Vis absorption change characteristically and consequently, structural transformations could be observed in FTIR and NMR spectra. For example, sharp signals of N-H, C-N, and C-H oscillations in the L-alanine spectrum are prone to inhomogeneous broadening in melanoidins prepared above 150 °C. These changes are caused due to formation of heterogeneous macromolecular structures and occur during condensation reactions that lead to an increasing loss of water from the melanoidins with increasing temperatures. Additionally, MALDI-ToF-MS indicates the polymerization of glyoxal/glyoxylic acid and EPR shows the formation of radical structures. KW - MALDI-ToF-MS KW - Melanoidine KW - Konjugate KW - Lebensmittel KW - MALDI-ToF-MS KW - L-alanine KW - D-glucose KW - Maillard reaction KW - FTIR spectroscopy KW - EPR spectroscopy KW - Melanoidin KW - NMR spectroscopy PY - 2018 DO - https://doi.org/10.1016/j.foodchem.2017.11.115 SN - 0308-8146 VL - 245 SP - 761 EP - 767 PB - Elsevier Science CY - Amsterdam, NL AN - OPUS4-44018 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hornemann, A. A1 - Eichert, D. A1 - Flemig, Sabine A1 - Ulm, G. A1 - Beckhoff, B. T1 - Qualifying label components for effective biosensing using advanced high-throughput SEIRA methodology JF - Physical chemistry, chemical physics N2 - The need for technological progress in bio-diagnostic assays of high complexity requires both fundamental research and constructing efforts on nano-scaled assay recognition elements that can provide unique selectivity and design-enhanced sensitivity features. Nanoparticle induced sensitivity enhancement and its application related to multiplexed capability Surface-Enhanced InfraRed Absorption (SEIRA) assay formats are well suitable for these purposes. The potential of diverse fluorophore–antibody conjugates, being chemisorbed onto low-cost gold nanoparticulate SEIRA substrates, has been explored with respect to their spectral discriminability. These novel biolabels deliver molecular SEIRA fingerprints that have been successfully analyzed by both uni- and multivariate analyzing tools, to discriminate their multiplexing capabilities. We show that this robust spectral encoding via SEIRA fingerprints opens up new opportunities for a fast, reliable and multiplexed high-end screening in biodiagnostics. KW - SEIRA methodology KW - bio-diagnostic KW - nanotechnology PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351389 DO - https://doi.org/10.1039/C4CP05944A SN - 1463-9076 SN - 1463-9084 VL - 17 IS - 14 SP - 9471 EP - 9479 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-35138 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hornemann, A. A1 - Drescher, Daniela A1 - Flemig, Sabine A1 - Kneipp, Janina T1 - Intracellular SERS hybrid probes using BSA-reporter conjugates JF - Analytical and bioanalytical chemistry N2 - Surface-enhanced Raman scattering (SERS) hybrid probes are characterized by the typical spectrum of a reporter molecule. In addition, they deliver information from their biological environment. Here, we report SERS hybrid probes generated by conjugating different reporter molecules to bovine serum albumin (BSA) and using gold nanoparticles as plasmonic core. Advantages of the BSA-conjugate hybrid nanoprobes over other SERS nanoprobes are a high biocompatibility, stabilization of the gold nanoparticles in the biological environment, stable reporter signals, and easy preparation. The coupling efficiencies of the BSA–reporter conjugates were determined by MALDI-TOF-MS. The conjugates' characteristic SERS spectra differ from the spectra of unbound reporter molecules. This is a consequence of the covalent coupling, which leads to altered SERS enhancement and changes in the chemical structures of the reporter and of BSA. The application of the BSA–reporter conjugate hybrid probes in 3T3 cells, including duplex imaging, is demonstrated. Hierarchical cluster analysis and principal components analysis were applied for multivariate imaging using the SERS signatures of the incorporated SERS hybrid nanoprobes along with the spectral information from biomolecules in endosomal structures of cells. The results suggest more successful applications of the SERS hybrid probes in cellular imaging and other unordered high-density bioanalytical sensing. KW - Bovine serum albumin KW - Nanosensor KW - SERS multiplexing KW - 3T3 cells KW - Gold nanoparticles KW - Hybrid nanoprobe KW - Rinderserumalbumin KW - Albumin KW - SERS KW - Konjugate KW - Conjugates KW - Cell KW - Zelle PY - 2013 DO - https://doi.org/10.1007/s00216-013-7054-3 SN - 1618-2642 SN - 1618-2650 VL - 405 IS - 19 SP - 6209 EP - 6222 PB - Springer CY - Berlin AN - OPUS4-29819 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -