New approach for the step by step control of magnetic nanostructure functionalization.

This paper describes the synthesis, functionalization, and multitechnique analysis of magnetic nanoparticles. The synthetic method involves the covering of a magnetite nucleus by a silica layer and the further functionalization with different fluorophores via a cross-linker molecule. All synthetic intermediates were analyzed by fluorescence spectroscopy and AC magnetic susceptibility. For one of the considered molecules, a further investigation with STEM, EDXS, and DLS has been conducted in order to validate the proposed magnetic results. The comparison between the two techniques is used to ensure a complete characterization of the product confirming the success of the synthesis. By comparing the magnetic and the fluorescence measurements, we also demonstrate the effectiveness of AC susceptibility as a robust and versatile technique to follow the synthesis of complex magnetic nanostructures regardless of the nature of the functionalization.