Magnetite nanoparticles coated with alkyne-containing polyacrylates for click chemistry

New magnetic core shell nanoparticles were synthesized consisting of magnetite cores and poly-(O-propargyl acrylate) shells. Strong fixing of the shells was achieved by primary anchoring phosphates or α-dihydroxydiphosphonates containing acrylate or methacrylate functionalities. The magnetic nanoparticles are attractive as supports for a variety of function which can be easily introduced by Cu-catalyzed alkyne azide cycloaddition (CuAAC, a click reaction). In this way, also the loading of the magnetic nanoparticles with propargyl units was determined by reaction with 4-azidoacetophenone and analysis of the supernatant. In order to demonstrate the attractiveness of the magnetic nanoparticles a novel azido-containing conjugate with biotin as recognition function and dansyl as fluorescence marker was introduced by CuAAC reaction. All NP show superparamagnetic behavior with high-saturation magnetization values and were further characterized by FTIR, photoelectron spectroscopy and TEM.