The Impact of Protein Corona Formation on PEGylated NT3- BDNF Nanoparticles - Distribution, Protein Release, and Cytotoxicity in Human Retinal Pigmented Epithelial Cell Model

Abstract

Abstract The adsorption of biomolecules on the nanoparticles’ surface ultimately depends on the intermolecular forces, which dictate the mutual interaction transforming their physical, chemical, and biological characteristics. Therefore, a better understanding of the adsorption of serum proteins and their impact on nanoparticle physicochemical properties is of utmost importance for developing nanoparticle-based therapies. We investigated the interactions between potentially therapeutic proteins: neurotrophin 3 (NT3), brain-derived neurotrophic factor (BDNF), and polyethylene glycol (PEG) in a cell-free system and a retinal pigmented epithelium cell line (ARPE-19). The variance of the physicochemical properties of PEGylated NT3-BDNF nanoparticles (NPs) in serum-abundant and serum-free systems were studied using transmission electron microscopy, atomic force microscopy, multi-angle dynamic, and electrophoretic light scattering. Next, we compared the cellular response of ARPE-19 cells after exposure to PEGylated NT3-BDNF NPs in either serum-free or complex serum environment by investigating protein release and cell cytotoxicity using ultracentrifuge, fluorescence spectroscopy and confocal microscopy. After serum exposure, the decrease in the aggregation of PEGylated NT3-BDNF NPs was accompanied by increased cell viability and BDNF/NT3 in vitro release. In contrast, in a serum-free environment, the appearance of positively charged NPs with hydrodynamic diameters up to 900 nm correlated with higher cytotoxicity, and limited BDNF/NT3 release into the cell culture media. Our study provides new insights into the role of protein corona when considering the PEGylated nano-bio interface with implications for cytotoxicity, NP’s distribution, and BDNF, NT3 release profiles in the in vitro setting.