  Molecular communications (MC), where molecules are used to encode, transmit,
and receive information, is a promising means of enabling the coordination of
nanoscale devices. The paradigm has been extensively studied from various
aspects, including channel modeling and noise analysis. Comparatively little
attention has been given to the physical design of molecular receiver and
transmitter, envisioning biological synthetic cells with intrinsic molecular
reception and transmission capabilities as the future nanomachines. However,
this assumption leads to a discrepancy between the envisaged applications
requiring complex communication interfaces and protocols, and the very limited
computational capacities of the envisioned biological nanomachines. In this
paper, we examine the feasibility of designing a molecular receiver, in a
physical domain other than synthetic biology, meeting the basic requirements of
nanonetwork applications. We first review the state-of-the-art biosensing
approaches to determine whether they can inspire a receiver design. We reveal
that nanoscale field effect transistor based electrical biosensor technology
(bioFET) is a particularly useful starting point for designing a molecular
receiver. Focusing on bioFET-based molecular receivers with a conceptual
approach, we provide a guideline elaborating on their operation principles,
performance metrics and design parameters. We then provide a simple model for
signal flow in silicon nanowire (SiNW) FET-based molecular receiver. Lastly, we
discuss the practical challenges of implementing the receiver and present the
future research avenues from a communication theoretical perspective.
