We have seen in the different sections of this book that bioelectronics, born in the early 1990s [1], has expanded over the years into several different branches. Bioelectronics now includes molecular components for electronics with thin-film [2] and protein-based [3] transistors, bio-memories [4], nanogap devices [5] for single-molecule electronics [6], and single enzymes immoblized on carbon nanotubes [7]. One of its major contributions to the state-of-the-art of the modern technology is the branch of biosensors, where bioelectronics has contributed to developing circuits for biomedical applications [8, 9], systems based on carbon nanotubes and proteins for applications in personalized therapy [10, 11], contactless monitors for measuring respiratory rate [12], and other very smart biomedical devices. Another fascinating branch is the development of biofuel cells based on enzymes [13], even implantable ones [14] that can exploit the body’s metabolism for their energy needs (Figure 44.1 illustrates a famous experiment in which the energy recovered from the body of a lobster by using an implanted biological fuel cell is used to power a watch). The more advanced developments in the field of electronics, such as epidermal electronics [15] and memristors [16], have enabled the development of biomimetic systems such as electronic skin [17], electronic brains with conventional CMOS technology [18], with memelements [19] or with organic polymers [20], and the design of synthetic genetic networks [21].

The new possibility of developing electronic skin as well as distributed neural systems brings us immediately to the area of bionics. Several innovative implantable devices have been proposed, some already on the market and others coming soon: artificial cochlea [22], eyes [23, 24], muscles [25], bacteria [26], and even full arms [27] that enable amputees to go back to playing guitar again (Figure 44.2). Human/machine interfaces have been pushed to the point of sending direct commands from the brain to artificial arms [28].