  This review provides a critical overview of current developments on
nanoelectronic biochemical sensors based on graphene. Composed of a single
layer of conjugated carbon atoms, graphene has outstanding high carrier
mobility and low intrinsic electrical noise, but a chemically inert surface.
Surface functionalization is therefore crucial to unravel graphene sensitivity
and selectivity for the detection of targeted analytes. To achieve optimal
performance of graphene transistors for biochemical sensing, the tuning of the
graphene surface properties via surface functionalization and passivation is
highlighted, as well as the tuning of its electrical operation by utilizing
multifrequency ambipolar configuration and a high frequency measurement scheme
to overcome the Debye screening to achieve low noise and highly sensitive
detection. Potential applications and prospectives of ultrasensitive graphene
electronic biochemical sensors ranging from environmental monitoring and food
safety, healthcare and medical diagnosis, to life science research, are
presented as well.
