Fig. 2: Graphene chemitransistor-based “electronic tongue” for taste differentiation.
From: An all 2D bio-inspired gustatory circuit for mimicking physiology and psychology of feeding behavior
a Optical image and b circuit schematic of an artificial gustatory taste receptor composed of two graphene chemitransistors connected in series. c Transfer characteristics, i.e., source-to-drain current (\({I}_{{{{{{\rm{DS}}}}}}}\)) plotted as a function of the gate voltage applied to the liquid solution (\({V}_{{{{{{\rm{LG}}}}}}}\)) for a constant source-to-drain voltage (\({V}_{{{{{{\rm{DS}}}}}}}\)) of 500 mV for two graphene chemitransistors with DI water as the gating liquid. d Response curve for the artificial taste receptor where the output voltage (\({V}_{{{{{{\rm{C}}}}}}}\)) is measured as a function of \({V}_{{{{{{\rm{LG}}}}}}}\) for a \({V}_{{{{{{\rm{DD}}}}}}}\) of 500 mV. Transfer characteristics of e graphene chemitransistor 1 and f graphene chemitransistor 2 and g the response curve for the artificial taste receptor subjected to five taste stimulants i.e., sweet, salty, sour, bitter, and umami. The corresponding \({V}_{{{{{{\rm{Dirac}}}}}}}\) values extracted from the transfet characteristics of h graphene chemitransistors 1 and i graphene chemitansistor 2 and j \({V}_{{{{{{\rm{C}}}}}}}\) obtained at \({V}_{{{{{{\rm{LG}}}}}}}\) = 0.1 V. confirming the distinctness of each taste stimuli. The nonoverlapping distributions of \({V}_{{{{{{\rm{Dirac}}}}}}}\) for each chemitransistor and unique \({V}_{{{{{{\rm{C}}}}}}}\) values obtained from the artificial taste receptor confirm successful taste differentiation and validate the use of graphene chemitransistors as the “electronic tongue” for our demonstration.
