Bioinspired and Biomimetic Logic Devices
The human mind treats a new idea the same way the body treats a strange protein; it rejects it.
P. B. Medawar
11.1 Information Processing in Natural Systems
Even in the most primitive organism the intracellular signalling and regulatory systems provide extraordinary flexibility and environmental adaptation. The inner regulatory networks respond to the external conditions and adjust cell physiology to changing circumstances. While these processes are associated with dynamic reaction–diffusion phenomena, we are still missing their exact transfer function. A simple alternative to describe these systems, at least qualitatively, is the application of Boolean logic. This analogy is possible because propagation of a chemical signal through the network depends on the interconnections of the circuitry in a similar way as the propagation of a signal through the networks of Boolean gates is determined by the structure of the network . This approach can be directly applicable in construction of bioinspired molecular logic devices when proper digitalization of input and output signals is assumed. This procedure also facilitates the understanding of casual relations between inputs and outputs of regulatory networks (Figure 11.1) . Along with the benefits of simplified analysis of complex chemical networks, it also results in filtration of small amplitude signals which may be important in complex reaction–diffusion processes.