Studying the Sensitivity of Graphene for Biosensor Applications

We have studied the response of graphene-film-based chips on SiC substrates (the relative change in the chip resistance) to coming into contact with fluorescein (C20H12O5) in a wide range of its concentrations in a phosphate-buffered saline solution: from 1 x 10(-3)to 1 x 10(4)ng/mL (seven orders of magnitude). Fluorescein detection seems to be a simple and cheap model experiment to study the sensory ability of graphene in the way of biochips manufacturing. It has been shown that chips with wide terraces on a surface with a step width of about 1000 nm and heights of up to 5 nm made it possible to construct the calibration dependences of chip response on fluorescein concentration.