The memory effect in floating nanodot gate field-effect-transistor (FET) was investigated by fabricating biomineralized inorganic nanodot embedded metal–oxide–semiconductor (MOS) devices. Artificially biomineralized cobalt (Co) oxide cores accommodated in ferritins were utilized as a charge storage node of floating gate memory. Two dimensional array of Co oxide core accommodated ferritin were, after selective protein elimination, buried into the stacked dielectric layers of MOS capacitors and MOSFETs. Fabricated MOS capacitors and MOSFETs presented a clear hysteresis in capacitance–voltage (C–V) characteristics and drain current–gate voltage (I _D–V _G) characteristics, respectively. The observed hysteresis in C–V and I _D–V _G are attributed to the electron and hole confinement within the embedded ferritin cores. These results clearly support the biologically synthesized cores work as charge storage nodes. This work proved the feasibility of the biological path for fabrication of electronic device components.