Surface modification and cellular uptake evaluation of Au-coated Ni80Fe20 nanodiscs for biomedical applications

Abstract

A nanofabrication technique based on self-assembling of polystyrene nanospheres is used to obtain magnetic Ni80Fe20 nanoparticles with a disc shape. The free-standing nanodiscs (NDs) have diameter and thickness of about 630 nm and 30 nm,respectively. The versatility of fabrication technique allows one to cover theNDsurface with a protective gold layer with a thickness of about 5 nm. Magnetization reversal has been studied by room-temperature hysteresis loopmeasurements inwater-dispersed free-standingNDs. The reversal shows zero remanence,high susceptibility and nucleation/annihilation fields due to spin vortex formation. In order to investigate their potential use in biomedical applications,the effect ofNDs coated with or without the protective gold layer on cell growth has been evaluated. A successful attempt to bind cysteine-fluorescein isothiocyanate (FITC) derivative to the gold surface of magnetic NDs has been exploited to verify the intracellular uptake of the NDs by cytofluorimetric analysis using the FITC conjugate.