Fluorescent-Magnetic Nanostructures Based on Polymer-Quantum Dots Conjugates

Summary: In this study it is presented the synthesis and the characterization of Fluorescent-Magnetic Nanostructures based on polymer-quantum dots conjugates. Polyvinyl alcohol (PVA) was used as the capping-ligand for the preparation of Cd_xMn_1-xS semiconductor nanocrystals via aqueous colloidal chemistry. Different substitution ratios of Cd²⁺ by Mn⁺² ions were investigated aiming at the formation of stable nanoparticles with photo-luminescent and semi-magnetic properties. UV-visible spectroscopy (UV-vis), photoluminescence spectroscopy (PL), Electric Paramagnetic Resonance Spectroscopy (EPR), and transmission electron microscopy (TEM) were used to characterize the formation and the relative stability of Cd_xMn_1-xS nanoparticles. The results have showed the influence of the Mn²⁺partially replacing Cd²⁺ in the optical behavior of the quantum dots (QDs) produced. In addition, the Cd_xMn_1-xS QDs have evidenced luminescent and semi-magnetic properties. Thus, the biocompatible water-soluble polymer was effective as ligand for synthesizing and stabilizing QDs conjugates with properties allowing them to be potentially applied as imaging and labeling probes in the biomedical field.