Dual Mode Atomic Force Microscopy and Interferometric Scattering Imaging of Single Au@Fe3O4 Nanoshell Synthesized for Biomedical Applications

Abstract

Imaging based on interferometric scattering (iSCAT) enhances the accuracy and temporal resolution in comparison to single-emitter-based techniques. In this research, we describe a combined method, which measures the size of individual magneto plasmonic Nano shells (MPNSs). The maghemite (Fe3O4) nanoparticles (SPIONs) with core diameter of 9.5 nm ± 1.4 nm is prepared by co-precipitation and coated by gold. The final dimension of polyvinyl pyrrolidine (PVP) stabilized MPNSs are 15.8 nm ± 3.5 nm measured by TEM. UV-Vis spectrophotometer and vibrating sample magnetometer (VSM) were used to study the optical and magnetization properties. The size of these nanoshells is determined independently by correlating their iSCAT and atomic force microscopy (AFM) images. By analyzing the number of single MPNSs, an interference intensity distribution is obtained with a nominal diameter of 15.8 nm in agreement with the size distribution recorded by TEM. It seems, the combination of iScat and AFM is capable of producing high resolution images of individual nanoparticles.