Free-radical cross-linking of serum albumin molecules on the surface of magnetite nanoparticles in aqueous dispersion

A novel universal approach to cross-linking of protein macromolecules on the surface of magnetite nanoparticles has been developed. The approach is based on protein liability to free-radical modification, leading to the formation of intermolecular covalent cross-links. Free radicals are locally generated on the surface of nanoparticles. Stable coatings of serum albumin 3 nm thick are formed on the surface of magnetite nanoparticles. Using a set of physicochemical methods, it has been proven that stable coatings composed of protein macromolecules are formed around individual nanoparticles. The presence of reactive groups in the protein structure makes it possible to perform subsequent modification of the surface layers-in particular, to graft nonprotein drugs. The approach developed can be used to create superfine systems with desired surface properties for targeted delivery of drugs and biologically active substances.