Developing novel strategies for the functionalization of core–shell magnetic nanoparticles with folic acid derivatives

Abstract

In this work, we explore the development of new synthetic strategies leading to the formation of folic acid di-ester functionalized iron oxide-based magnetic nanoparticles. For this, initially, folic acid di-ester was converted into an acrylamide monomer through amidation of the primary amine site. Interestingly, esterification with a different acid chloride molecule carrying a long alkyl chain terminated with an azide group resulted into amidation of the secondary amine site. In a different set of experiments, magnetite nanoparticles decorated with a polymerization initiator, an acrylamide monomer, or a terminal alkyne group, were prepared. These folic acid and magnetic nanoparticles building blocks could then be combined in different ways to give rise to the targeted materials. In the first scheme, folic acid-based monomer could be polymerized through the initiating sites located at the surface of the magnetic nanoparticles. Alternatively, a random copolymerization between the folic acid-based monomer was carried out with the monomeric sites stabilizing the nanoparticles. Finally, the alkyne functionalities of the nanoparticles were coupled with the azide moieties of the folic acid derivatives. Thus, three different synthetic strategies were established for the formation of folic acid di-ester functionalized core–shell magnetic nanoparticles.