Conjugable, Antifouling, and Non-immunogenic Coatings for Gold Nanoparticles by Multivalent Grafting of Azide-Bearing Polyoxazoline Brushes

Inorganic nanoparticles (NP), particularly gold nanoparticles, hold great promise for biomedical applications. However, one of the major challenges in the implementation of therapeutic applications based on inorganic nanoparticles is the individuation of appropriate coatings, which are indeed responsible for stability, escape from the immune system, and further functionalization. In this paper, we explore the properties of the multi-azide-containing and highly nonfouling polymer PAcrAm-g-(PMCA, NH2, ND), based on poly(oxazoline) derivatives grafted to a poly(acrylamide), as a coating for gold nanoparticles that can grant stability and easiness of derivatization and can prevent nonspecific protein adhesion on gold nanoparticles (Au-NP). We found that the addition of the polymer to citrate-stabilized gold nanoparticles led to the formation of NP suspensions with excellent colloidal stability, as confirmed by dynamic light scattering (DLS), zeta potential, thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) investigations. In addition, the AuNP coating strongly decreases the protein adsorption corona and does not activate dendritic cells (DCs), showing low immunogenicity and potentially decreasing the NP clearance by the mononuclear phagocyte system.