Characterizing the biocorona formed on nanomaterials interacted with food matrix

The presence of nanomaterials (NMs) in food is likely to increase because of intentional addition as well as entry from environmental matrices as contaminants. The consequences of NMs interactions with food components, however, have not been studied adequately to understand potential health implications of NM exposure through food. Probing NM-biomolecule interface is challenging because of the lack of established protocols and instrumental capabilities. We examined NM (of Titanium dioxide (TiO2) and silica (SiO2)) surface to understand potential adverse health effects of NMs added in food. Our studies using synchrotron radiation-based analysis of milk interacted particles helped visualize the structure of biocorona on the surface. Spectral fitting of the O K-edge stack was performed with different combinations of the major biomolecules and TiO2 spectra.  The O K-edge X-ray absorption TiO2 spectrum was similar to that of anatase. The distributions of lipids and saccharides were similar when they were separately included in the spectral fitting with protein and TiO2. As such, our analysis showed that biomolecules from milk were associated with the TiO2 and it appears that there was some separation of the proteins and lipids surrounding the TiO2 particles and lipid/saccharide layer was more prominent than protein layer.  Along with other analytical tools such as FTIR, our studies revealed accumulation of biocorona on the surface of NMs used in food and the change in protein conformation ensuing protein binding to NM.