Surface modification of magnetic nanoparticles using asparagines-serine polypeptide designed to control interactions...

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.