Micro-raman spectroscopy and VP-SEM/EDS applied to the identification of mineral particles and fibres in histological sections

Histological sections of a patient affected by an important respiratory disease were analysed firstly by optical microscope(OM) - crossed polarisers - to identify the presence of incorporated inorganic particles, with particular attention to the fibrous ones. Then, the particles/fibres that were found were studied both with micro-Raman spectroscopy and variable pressure scanning electron microscopy with energy-dispersive spectroscopy (VP-SEM/EDS). The two techniques allowed the in situcharacterisationoftheinorganicphaseswithoutdisintegrationoftheorganicmatter.Micro-Ramanspectroscopywasable toidentifythevibratingchemicalgroupsofthemineralphaseassociatedwiththeinorganicgrainwhilethecrystallinestructure was preserved by the biological system. The VP-SEM/EDS characterisation, defining the elemental chemical composition of the analysed particle/fibre, allowed confirmation of the mineral phase deducible from spectroscopic data or its identification with certainty when the spectroscopic data were not exhaustive.