Switchable Electrodes: How Can the System Complexity be Scaled up?

Electrodes modified with different signal‐responsive materials were designed as switchable electrochemical interfaces controlled by various physical or chemical signals. Electrodes with the electrochemical activity switched ON and OFF by light signals were developed using monolayers or thin films of photoisomerizable compounds. Functionalized magnetic particles associated with the electrode surfaces allowed the switching processes controlled by an external magnetic field. Electrochemical transformations proceeding at modified electrode surfaces upon application of different potentials were able to switch the interfacial resistance between low and high values, thus affecting electrochemical properties of the surfaces. Electrode surfaces functionalized with materials responding to chemical signals allowed the switching processes controlled by chemical or biochemical inputs. Most of the designed switchable electrode interfaces have very limited possibilities for scaling up the complexity of the information processing systems associated with the electrode surfaces. Recent advances in biocomputing and specifically in the design of enzyme‐based logic systems allow their coupling with switchable electrodes resulting in very sophisticated interfaces for processing biochemical information and its transduction into electronic signals. Future applications of the signal‐responsive electrodes integrated with the biocomputing systems in ‘smart’ biochemically controlled biosensors, biofuel cells and chemical actuators could be envisaged.