Surface modification of magnetic nanoparticles using asparagines-serine polypeptide designed to control interactions with cell surfaces

Surface modification is an important part of the fabrication of nanoparticles that have specific properties and functions. Here we describe the development of a functional polypeptide and a simple available technology for surface modification of nanoparticles. A NS polypeptide, which is 100 amino acids composed of repeated units of four asparagine and one serine residue (NS), as a molecule for nanoparticle surface modification was designed. Modification of the surface of a magnetic nanoparticle with the NS polypeptide results in reduction of particle-particle and particle-cell interactions. When NS polypeptide is used in single fusion protein as a linker to display protein G on nanoparticles, the nanoparticle acquires the capacity to specifically bind target cells and to avoid nonspecific adsorption of non-target cells. This technology, incorporating a functional polypeptide, may represent a completely new strategy for surface modification of nanoparticles for use in a variety of cell-associated applications.