Toward optimal spatial and spectral quality in widefield infrared spectromicroscopy of IR labelled single cells.

International audienceAdvancements in widefield infrared spectromicroscopy have recently been demonstrated following the commissioning of IRENI (InfraRed ENvironmental Imaging), a Fourier Transform infrared (FTIR) chemical imaging beamline at the Synchrotron Radiation Center. The present study demonstrates the effects of magnification, spatial oversampling, spectral pre-processing and deconvolution, focusing on the intracellular detection and distribution of an exogenous metal tris-carbonyl derivative 1 in a single MDA-MB-231 breast cancer cell. We demonstrate here that spatial oversampling for synchrotron-based infrared imaging is critical to obtain accurate diffraction-limited images at all wavelengths simultaneously. Resolution criteria and results from raw and deconvoluted images for two Schwarzschild objectives (36×, NA 0.5 and 74×, NA 0.65) are compared to each other and to prior reports for raster-scanned, confocal microscopes. The resolution of the imaging data can be improved by deconvolving the instrumental broadening that is determined with the measured PSFs, which is implemented with GPU programming architecture for fast hyperspectral processing. High definition, rapidly acquired, FTIR chemical images of respective spectral signatures of the cell 1 and shows that 1 is localized next to the phosphate- and Amide-rich regions, in agreement with previous infrared and luminescence studies. The infrared image contrast, localization and definition are improved after applying proven spectral pre-processing (principal component analysis based noise reduction and RMie scattering correction algorithms) to individual pixel spectra in the hyperspectral cube

Synthesis and photophysical properties of iron-carbonyl complex-coumarin conjugates as potential bimodal IR-fluorescent probes

An expedient synthesis of the first examples of iron-carbonyl complex-coumarin conjugates is reported. 7-Amino/7-hydroxycoumarin derivatives have been readily derivatized through an easily implemented single-step reaction involving the tricarbonyl(η5-cyclohexadienyl)iron(1+) cation [(C6H7)Fe(CO)3]+. The scope and limitations of this N-/O-alkylation reaction were also investigated. The fluorescence properties of these novel metal-carbonyl complexes have been studied and support their further use as valuable building blocks in the design of bimodal contrast agents for combined vibrational and fluorescence imaging

Photothermal IR-Spectromicroscopy for Subcellular Imaging: an Example of Cellular Mapping of a Metal-Carbonyl Exogenous Compound,

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Synthesis and superoxide dismutase-like activity of new manganese(III) complexes based on tridentate N2O ligands derived from histamine

We have obtained two new manganese(III) complexes based on tridentate ligands bearing imidazole and phenol moieties. The structure of the chosen ligands favored the Mn(III) oxidation state due to the compatibility of the geometry of the complexes with a Jahn–Teller tetragonal distortion, as was shown by X-ray diffraction for one of the complexes. This induced a lowering of the oxidation potential for the Mn(III)/Mn(II) couple, which can be correlated to the superoxide dismutase-like (SOD-like) activity of the complexes, compared with a previously published Mn(III) complex