1 What is bioelectronics ? Sandro

Although the term was first proposed in 1968, the birth of bioelectronics as we know it today is much more recent. In fact, the first meaning of the word bioelectronics was the intermolecular electron transfer found in biological systems [1], while its modern meaning is quite different, as discussed in this chapter. Tony Turner, founder and Editor-in-Chief of the Elsevier journal Biosensors and Bioelectronics, wrote in 2005: “Bioelectronics is a recently coined term for a field of research that works to establish a synergy between electronics and biology” [2]. Over the years, his journal became the main forum in the field of bioelectronics. The journal originally appeared in 1985 with the simple name of Biosensors, and the title was expanded to include the term Bioelectronics in 1992 [2]. The expressed scope of the journal [3] explains that a key aspect of bioelectronics is the interface between biological materials and electronics. To better understand the modern state of the field, we can also consider the meaning of “advanced bioelectronics” as mentioned in April 2013 by the National Institute of Standards and Technology (NIST – an agency of the US Department of Commerce) and represented by the example of electronic DNA sequencing, as supported by singlemolecule mass spectrometry to develop innovative electronic devices for healthcare [4]. The authors [4] refer to devices in which an electric field drives individual molecules of single-stranded DNA through a nanometer-scale pore (Figure 1.1). That approach is a step toward applications for rapid sequencing of DNA [5] and DNA transcription complexes [6], and could lead to further developments in protein sequencing [7] too. The application is clearly focused on devices for healthcare and, more generally, includes both diagnostic and therapeutic tools. We could briefly summarize bioelectronics as “the application of electronics in the field of biology”, and, in fact, IUPAC accepts the definition of bioelectronics as “the application of biomolecular principles to microelectronics such as in biosensors and biochips” [8]. However, in the literature we actually havemuchmore than that. It is easy to find extensions of bioelectronics into the area of electronic components and circuits that include proteins or other biological macromolecules. For example, it has been outlined that this field might include biotemplated circuitries [9]. To quote the Elsevier journal Biosensors and Bioelectronics, already mentioned above as a leader in the field: “The emerging field of bioelectronics seeks to exploit biology in conjunction with electronics in a wider context encompassing, for example, biological fuel cells, bionics and biomaterials for information processing, information storage, electronic components and actuators” [3]. Another historical pioneer of the field, Wolfgang Göpel, wrote in 1998: “Bioelectronics is aimed at the direct coupling of biomolecular function units of high molecular weight and extremely complicated molecular structure with electronic or optical transducer devices” (Figure 1.2) [10]. Two key points are introduced here: the “direct coupling” and the “high molecular weight”. The first indicates an intimate integration between biomolecular principles and microelectronics. The second implies large biomolecules such as proteins or complex biological systems such as cells or bacteria. That means we need to integrate biomolecular functions with extremely complicated biological structures. However, “organic bioelectronics” has been introduced, too, by proposing, for example, organic polymers for drug delivery systems [11]. Now, we cannot say that “a polymer” can be seen as “an extremely complicated molecular structure” and, therefore, we need to