Iron oxide (Fe3O4) non‐specific superparamagnetic nanoparticles of 30 nm size are introduced into human embryonic kidney (HEK‐293) cells by intracellular uptake. The nanoparticles are magnetised by two superimposed magnetic fields, an externally applied DC field and an AC field generated by the high‐frequency current flowing through Co64.5Fe2.5Cr3Si15B15 amorphous ribbons. The resulted fringe fields from the nanoparticles are detected via the magnetoimpedance change in the ribbons covered and uncovered by thin gold layer. The gold covering is considered an improvement due to its biocompatibility and because it avoids the biocorrosion process on the ribbon. The MI responses in both cases are clearly dependent on the presence of the magnetic nanoparticles inside the cells and on the value of the external field.