Preliminary observation on the interactions between fine atmospheric particulate matter (PM2.5) and human alveolar epithelial cells (A549)

Fine atmospheric particulate matter (PM2.5) was collected in Milan during winter at Torre Sarca site, representative of background urban atmospheric pollution concentrations. Human alveolar epithelial A549 cells were subsequently exposed to different particle doses for increasing time. PM2.5 morphology, as well as cell-particle interaction, were characterized by light microscopy, transmission electron microscopy and Raman spectroscopy. Based on previous theoretical studies of molecular dynamics and vibrational spectroscopy (Zerbi et al. 2006, Zerbi 2007) we developed a method to extract from the Raman spectra information on the molecular properties of different carbonaceous materials. It has been shown that PM2.5 is progressively internalized in cells (Gualtieri et al., 2007). Of particular interest is the preliminary observation that the Raman spectra of a carbon particulate (PM2.5) isolated from its surrounding or encapsulated in a cellular matrix, like that of alveolar epithelial cells, showed differences. It indicates that some kind of interaction at the molecular level has occurred. Further work is in progress.