  The main aim of this study is to report basic knowledge on how a protein
corona (PC) could affect or modify the way in which multifunctionalized
nanoparticles interact with cells. With this purpose, we have firstly optimized
the development of a target-specific nanocarrier by coupling a specific
fluorescent antibody on the surface of functionalized lipid liquid nanocapsules
(LLNCs). Thus, an anti-HER2-FITC antibody ({\alpha}HER2) has been used, HER2
being a surface receptor that is overexpressed in several tumor cells.
Subsequently, the in vitro formation of a PC has been developed using fetal
bovine serum supplemented with human fibrinogen. Dynamic Light Scattering
(DLS), Nanoparticle Tracking Analysis (NTA), Laser Doppler Electrophoresis
(LDE), and Gel Chromatography techniques have been used to assure a complete
physico-chemical characterization of the nano-complexes with
(LLNCs-{\alpha}HER2-PC) and without (LLNCs-{\alpha}HER2) the surrounding PC. In
addition, cellular assays were performed to study the cellular uptake and the
specific cellular-nanocarrier interactions using the SKBR3 (high expression of
HER2) breast cancer cell line and human dermal fibroblasts (HDFa) (healthy cell
line without expression of HER2 receptors as control), showing that the SKBR3
cell line had a higher transport rate (50-fold) than HDFa at 60 min with
LLNCs-{\alpha}HER2. Moreover, the SKBR3 cell line incubated with
LLNCs-{\alpha}HER2-PC suffered a significant reduction (40%) in the uptake.
These results suggest that the formation of a PC onto LLNCs does not prevent
specific cell targeting, although it does have an important influence on cell
uptake.
