Large Protein Absorptions from Small Changes on the Surface of Nanoparticles

Due to their ultrasmall size, nanoparticles possess distinct properties, when compared with the bulk form of the exact same material. These unique properties are now being exploited in biology and biomedicine in order to probe biological systems and deliver biosensors or drugs into the targeted areas. However, relatively little is known about the interaction of nanoscale objects with living systems. In a biological fluid for example, various proteins associate with nanoparticles. The small size and high curvature angles of nanoparticles bias the physicochemical properties, sizes, and amounts of the proteins presented on their surface. The differential display of proteins bound to the surface of nanoparticles can influence the tissue distribution, cellular uptake, and biological effects of nanoparticles. This study is aimed at verifying the influence of surface roughness of nano-objects on the composition of the corresponding protein corona. A novel approach was used to synthesize magnetic core–shell nanoparticles, with smooth or rough gold shells, by creating either uniform or nonuniform polymeric gaps between the core and the shell. The interactions between the SPIONs and human plasma were probed. Transmission electron microscopy, together with atomic force microscopy, confirmed the formation of various surface topographies on the SPIONs. Field cooling magnetization measurements indicated a decrease in magnetization as a result of gold-coating of nanoparticles. Nuclear relaxivity measurements yielded significantly greater transverse relaxivity in SPIONs, indicating the potential application of these nanoparticles as alternative MRI contrast agents, allowing imaging modality. These results, therefore, confirm the significance and potential applications of emerging iron nanoparticles associated with nanoengineered coatings in the field of biomaterials engineering and nanomedicine.