Analytische Chemie
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- D-glucose (1)
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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.
Bio-diagnostic assays of high complexity rely on nanoscaled assay recognition elements that can provide unique selectivity and design-enhanced sensitivity features. High throughput performance requires the simultaneous detection of various analytes combined with appropriate bioassay components. Nanoparticle induced sensitivity enhancement, and subsequent multiplexed capability Surface-Enhanced InfraRed Absorption (SEIRA) assay formats are fitting well these purposes. SEIRA constitutes an ideal platform to isolate the vibrational signatures of targeted bioassay and active molecules. The potential of several targeted biolabels, here fluorophore-labeled antibody conjugates, chemisorbed onto low-cost biocompatible gold nano-aggregates substrates have been explored for their use in assay platforms. Dried films were analyzed by synchrotron radiation based FTIR/SEIRA spectro-microscopy and the resulting complex hyperspectral datasets were submitted to automated statistical analysis, namely Principal Components Analysis (PCA). The relationships between molecular fingerprints were put in evidence to highlight their spectral discrimination capabilities. We demonstrate that robust spectral encoding via SEIRA fingerprints opens up new opportunities for fast, reliable and multiplexed high-end screening not only in biodiagnostics but also in vitro biochemical imaging.
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.