Nanoparticles (NPs) are versatile tools for nanomedicine and tuning features such as material, size and charge, imaging and targeting can be accomplished. However, NPs behaviour in vivo is modified upon interaction with the biological matter and formation of a protein corona (PC) coating the NP. The PC determines the NP biological identity and it is the ultimate interface with the surrounding environment. Therefore, a deep characterization of the NPs in biological media is important to predict adverse effects and improve NPs design.
The aim of this thesis was to understand the effect of the PC formation from different biological fluids on NP- membranes interactions. For this purpose, core-shell gold and magnetite NPs coated by poly-maleic anhydride and pegylated were characterized my means of scattering, microscopic and spectroscopic techniques.
Such NPs were characterized in serum and PC complexes were isolated. Sucrose-gradient ultracentrifugation (UC) was used guaranteeing quantitative recovery of homogeneous NP PC populations, simultaneously present in situ, and a lower impact on the in situ structures compared to conventional centrifugation protocols.
NP interactions with supported lipid bilayers (SLB) were investigated by QCM-D and neutron reflectometry allowing resolving at the sub-nanometer scale any structural reorganization of the SLB upon NP application. Carboxylated NPs generally caused lipid hydration with different mechanisms, while HC NPs compared to in situ NPs and pure FBS had a lower impact on the bilayers possibly indicating a major impact of the soft corona.
The last part of the project was focused on the PC evolution during simulated in vitro digestion with NPs. UC was suitable to isolate PC complexes from gastric and intestinal phases and SDS-PAGE and LC-MS suggested a PC ability to protect peptides from digestion degradation. The biological impact of the PC complexes was studied by confocal microscopy on Caco-2 cells revealing cells morphological alterations
