The Energy Consumed by Electrochemical Molecular Machines as Self‐Sensor of the Reaction Conditions: Origin of Sensing Nervous Pulses and Asymmetry in Biological Functions

For reactions involving molecular machines (artificial or biochemical), the evolution of the reaction energy, or that of any of its components, adapts to and senses the working thermal, chemical, or mechanical conditions. Here, the state of the art and the attained sensing equations of the oxidation/reduction of conducting polymers seen as replicating materials and reactions of the intracellular matrix of functional cells (molecular machines, ions and water) are reviewed. The adapting reaction energy in actuating muscles and other organs can originate the nervous pulses translating its quantitative energetic information (thermal, fatigue state and mechanical) to the brain. Besides, reversible oxidation/reduction charges originate a great asymmetry of the consumed reaction energies, which could explain why evolution has selected and improved the most efficient of the two reactions to drive full asymmetric biological functions such as muscle contraction or the flow of nervous signals. The material reaction drives volume variations and energetic adaptation, two simultaneous functions that have allowed the development of artificial sensing‐muscles postulated to replicate some primitive artificial proprioception. How natural muscles inform the brain about their physical and chemical conditions during actuation? Using conducting polymers as replicating materials (molecular machines, ions and water) of the intracellular matrix of functional cells, it is reviewed how the reaction energy, or any of its components, senses the reaction conditions. The sensing equations and technological or biological outlooks are presented.