Figure 1.

(a) DNA-aptamer-modified MPC SiNW-FET biosensor for dopamine; illustration of FET device for detecting exocytotic dopamine under hypoxic stimulation from living PC12 cells; (b) a semi-log plot of response as a function of dopamine concentration [17]. (c) Schematics of a graphene-based electrode used for measurements of DA; graphene electrode is mounted on a SiO₂/Si substrate, and a fluidic chamber is filled with PBS solution containing target dopamine; (d) SEM image of the graphene-based sensor array; AFM topographic image of CVD grown multilayer graphene (e) mechanism behind the FSCV measurements of dopamine; and (f) noticeable area-normalized electrochemical current (I_EC) response to the dopamine concentrations [18].