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

Abstract

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 enzymebased 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 signalresponsive electrodes integrated with the biocomputing systems in smart biochemically controlled biosensors, biofuel cells and chemical actuators could be envisaged.

Electrochemical Nanotransistor from Mixed‐Polymer Brushes

“…Their applications for controlled surface wettability, [6,7] thin-films permeability, [8,9] catalysis, [10] and particularly for assembling modified electrodes, [11] used in switchable sensors, [12] fuel cells, [13] and memory units, [14] resulted in novel materials, devices, and systems. [15,16] Recent integration of signal-responsive materials, functionalized switchable interfaces and biocomputing systems processing biochemical information resulted in the novel concept of biochemically controlled ''smart'' materials with built-in Boolean logic.…”

Light and Redox Switchable Molecular Components for Molecular Electronics

“…[37] Electrochemistry allows entire monolayers of redox active molecular switches to be addressed at electron transfer limited rates and with high sensitivity. An example of this is shown in Fig.…”

Switchable Biosensor Controlled by Biocatalytic Process

“…The application of an extern potential which had reduced O 2 electrochemically, resulted in concomitant hydrogen ions consumption at the electrode interface, thus yielding a higher pH value and triggering P4 VP brush restructuring on the electrode surface. One had developed enzyme logic systems in another experiment, producing pH changes due to biochemical reactions (from enzyme in solution) activated by different combinations of chemical input signals [7]. But such systems operated upon local pH changes generated in the interfaces, without changing solution properties.…”

“…Recently, stimuli-responsive thin polymer films were used to activate the ON-OFF switch during electrode activities by sending logically processed biochemical signals [7]. Due to unique properties, polymer brushes have been applied to this particular application.…”