The Effect of pH and Magnetic Field on the Fluorescence Spectra of Fluorescein Isothiocyanate Conjugated SPION- Dendrimer Nanocomposites

Abstract

In this study, fluorescent dendro-nized magnetic nanoparticles (FDMNPs) with their unique pH sensitive nature were synthesized for biomedical applications. First, superparamagnetic iron oxide nanoparticles (SPIONs) were prepared by coprecipitation of F e +2 and F e +3 with N H 4 O H, and then modified by amino silane. Polyamidoamine (PAMAM) dendrimer were coated on the SPION-APTS surface using Michel addition method and grew from generation 0.5 to 3. In the final step of synthesis, the reaction between isoslulfosyanic groups of fluorescein isothiocyanate (FITC) and amine terminal groups of DMNPs was lead to the formation of magnetic fluorescent nanocomposites. The FDMNPs were studied using Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-visible spectroscopy, fluorescence spectroscopy, vibrating-sample magnetometery (VSM) ), zeta potential ,and Dynamic Light Scattering (DLS). The size of SPIONs and FDMNPs were about 10 nm and 14 nm, respectively. The possibility of conjugating a large number of fluorescein isothiocyanate (FITC) molecules on the SPIONs together with high amount of magnetization saturation ,Ms (52 emu/g in our case) and other unique characteristics have nominated FDMNPs as a suitable candidate for biomedical applications.