Bioelectronics

TL;DR: Bioelectronics is focused on the transfer of electrons between molecules. However, this concept has not been widely adopted in biology due to the weak nature of charge transfer in living systems.

Abstract: Many years ago, working with J. A. McLaughlin, I came to the conclusion that, in animal tissues, cell division may be controlled by two antagonistic substances, an inhibitor and a promotor (1). In plants, growth is known to be controlled by such antagonists, which have been isolated and identified (2). My arduous efforts to isolate the inhibitor of animal tissues failed, and this made it necessary to look more deeply into the problem. Present-day biology is dominated by the molecular outlook-the view that living systems are built of isolated small units, molecules, and that in order to understand life we only have to know these molecules, the rest will take care of itself. Joseph Weiss discovered in 1942 (3) that in certain molecular complexes an electron can go spontaneously from one molecule (the donor) to another (the acceptor), a reaction he called "charge transfer." Weiss worked with complexes formed by strongly oxidizing and reducing agents. Later, attention was given to charge transfer in which the energy of light moves electrons from one molecule to another. This was called a "weak transfer" to distinguish it from the "strong" transfer studied by Weiss, in which the transfer was spontaneous. R. S. Mulliken cleared up the quantum mechanics of these reactions (4) and systematized them. He preferred the name "DA [donor-acceptor] interactions" to "charge transfer." Though in several instances DA interactions between biological substances have been produced in vitro, the idea of charge transfer found no real place in biology. Strong charge transfer could play no role because the presence of