Surface modification of magnetite hybrid particles with carbohydrates and gold nanoparticles via "click" chemistry

An efficient method is described to synthesize magnetic particles based on divinylbenzene-co-pentafluorostyrene suitable for further chemical modification and incorporation of active groups, in particular, carbohydrates and gold nanoparticles. The magnetic hybrid particles were prepared via seeded precipitation polymerization consisting of the radical copolymerization of pentafluorostyrene and divinylbenzene in the presence of modified magnetite nanoparticles as seeds. Magnetite nanoparticles were first prepared by a thermal decomposition process followed by their modification with the bioinspired dopamine methacrylamide to incorporate vinyl groups at the particle surface. Then, pentafluorostyrene and divinylbenzene are polymerized through the interface of the magnetite nanoparticles to form the crosslinked polymeric shell. Afterwards, carbohydrate moieties were attached to the particles by the so-called thiol-para-fluorine "click" reaction based on the coupling of acetylated beta-D-thioglucopyranose onto pentafluorostyrene via nucleophilic substitution of para-fluorine. Moreover, the fluorinated hybrid particles reacted with 1,2-ethanedithiol in order to introduce thiol groups at the surface that were used further as platforms to stabilize the nucleation and growth of gold nanoparticles. The resultant functional particles with potential interest in recognition processes and catalysis amongst others are responsive to external magnetic fields, making the particles easy to remove from the media.