Immobilization of Fe@Au superparamagnetic nanoparticles on polyethylene

Iron nanoparticles with gold shell (Fe@Au) have the advantage of desirable magnetic properties of the Fe and the inertness of Au. The Au shell can be utilized as well for specific binding of the nanoparticles to activated surfaces with e.g. thiol groups, which have good affinity to Au. Colloidal Fe@Au nanoparticles with sizes of 10 nm that contain magnetic Fe core and Au shell were successfully synthesized through reverse micelle method. Superparamagnetic Fe@Au nanoparticles were functionalized by dithiol molecules and then immobilized on plasma activated surface of high density polyethylene foils. The success of this process was studied by X-ray photoelectron spectroscopy, 2-4% Fe content was found on the surface of the samples. Influence of the binding process on optical properties of the material was evaluated by UV Vis spectroscopy, evolution of surface structure of the samples was observed atomic force microscopy. Our findings could extend the current application of superparamagnetic nanoparticle and bring new insight into the application of such kind of materials in lab-on-a-chip instruments.