Functionalization of gold and glass surfaces with magnetic nanoparticles using biomolecular interactions

Advances in nanotechnology have enabled the production and characterization of magnetic particles with nanometer-sized features that can be functionalized with biological recognition elements for clinical and biosensing applications. In the present study the synthesis and interactions between self assembled monolayers (SAMs) and functionalized nanoparticles have been characterized. Size and shape of magnetic nanoparticles synthesized wet chemically starting from ferrous and ferric salts were verified by transmission electron microscopy (TEM). These nanoparticles were then conjugated with FITC-labeled streptavidin through carbodiimide (EDC) chemistry. SAMs of thiol-capped biotins were synthesized on gold surfaces for capture of the conjugated nanoparticles. Characterization of nanoparticle functionalization and binding was performed using fluorescent microscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS). FT-IR spectra confirm the binding of biotin on gold via sulphur linkages. Fluorescent microscopy and XPS show streptavidin bound to the biotinylated gold surfaces. Elemental characterization from EDS indicates the binding of streptavidin-conjugated nanoparticles to biotinylated gold surfaces. Together, these techniques have application in studying the modification and behavior of functionalized nanoparticles for biological and other applications