The Internet of Bio-Nano Things (IoBNT) is an emerging area of networking where seamless interconnection between biological and electrical nanotechnology-enabled devices is envisioned to enable disruptive applications. This paper focuses on characterizing the propagation of information (communication channel) through an interface between the biological and the electrical domains, whose components are commonly used as part of biosensing systems. On top of its sensing capabilities, this interface, based on electrochemical transduction, is here innovatively modeled and characterized in terms of communication performance, a key parameter in the context of IoBNT. In particular, the transduction at the basis of this channel is enabled by interactions with a circuit electrode of reduction-oxidation (redox) chemical reactions. Redox reactions are among the building blocks of communication channels in biological cells and tissues. Based on the underlying physical and chemical processes, an analytical system model is detailed for the channel. Based on the latter, an experimentally validated computational model is formulated to enable the empirical estimation of its performance through simulation data. The estimation of Signal-to-Noise Ratio (SNR), Limit of Detection (LoD), and Limit of Quantification (LoQ) are followed by frequency-based analysis of the channel and the estimation of an upper-bound to its information capacity. Design rules based on a trade-off between the dimension of the transducer and its communication performance are derived to aid in the integration of this communication channel into future IoBNT devices.

Biology is well-known for its ability to communicate through (i) molecularly-specific signaling modalities and (ii) a globally-acting electrical modality associated with ion flow across biological membranes. Emerging research suggests that biology uses a third type of communication modality associated with a flow of electrons through reduction/oxidation (redox) reactions. This redox signaling modality appears to act globally and has features of both molecular and electrical modalities: since free electrons do not exist in aqueous solution, the electrons must flow through molecular intermediates that can be switched between two states - with electrons (reduced) or without electrons (oxidized). Importantly, this global redox modality is easily accessible through its electrical features using convenient electrochemical instrumentation. In this review, we explain this redox modality, describe our electrochemical measurements, and provide four examples demonstrating that redox enables communication between biology and electronics. The first two examples illustrate how redox probing can acquire biologically relevant information. The last two examples illustrate how redox inputs can transduce biologically-relevant transitions for patterning and the induction of a synbio transceiver for two-hop molecular communication. In summary, we believe redox provides a unique ability to bridge bio-device communication because simple electrochemical methods enable global access to biologically meaningful information. Further, we envision that redox may facilitate the application of information theory to the biological sciences.