Graphene Biosensors Operated in DC Transistor and AC Electrochemical Modes for DNA Sensing

Graphene is considered for different technological applications, particularly biosensing, due to its unique electrical and electronic properties, such as its ambipolar transport and ballistic electron dynamics. Thus, graphene-based setups that allow fast and simple access to its quantum properties are required to advance in the design of high-performance devices. Non-destructive methodologies based on small electrical perturbations offer the possibility of accessing graphene's electronic structure (V-shaped DOS) in mild experimental conditions. Here, we present a device comprising 20 graphene functionalized channels per chip operated in two modes: a 3-terminal DC transistor and a 2-terminal AC electrochemical setup. Both setups resolved the graphene electronic structure, used as a transduction signal to detect four brain tumor single-stranded DNA biomarkers with a single genetic mutation. The device detected the four cancer biomarkers in the attomolar range (∼ 10 aM) in DC transistor mode. A detection limit of 1 aM was achieved in the AC electrochemical mode for the DNA mutation studied. We present a CMOS integrated circuit for fast readout of the multiplexed graphene sensor arrays.