Electrode interfaces switchable by physical and chemical signals for biosensing, biofuel, and biocomputing applications

Abstract

This review outlines advances in designing modified electrodes with switchable properties controlled by various physical and chemical signals. Irradiation of the modified electrode surfaces with various light signals, changing the temperature of the electrolyte solution, application of a magnetic field or electrical potentials, changing the pH of the solutions, and addition of chemical/biochemical substrates were used to change reversibly the electrode activity. The increasing complexity in the signal processing was achieved by integration of the switchable electrode interfaces with biomolecular information processing systems mimicking Boolean logic operations, thus allowing activation and inhibition of electrochemical processes on demand by complex combinations of biochemical signals. The systems reviewed range from simple chemical compositions to complex mixtures modeling biological fluids, where the signal substrates were added at normal physiological and elevated pathological concentrations. The switchable electrode interfaces are considered for future biomedical applications where the electrode properties will be modulated by the biomarker concentrations reflecting physiological conditions.

Direct bioelectrocatalysis at the interfaces by genetically engineered dehydrogenase

“…51 Many of the immobilisation approaches explored so far result in a significant loss of catalytic enzymatic functionality, potentially due to the randomly introduced covalent bonds between the enzyme and the surface. 12,15 In this case, the authors added a new functionality to the enzyme to attain surface functionalisation ability; they first tested if the enzyme would retain its catalytic activity following the insertion of the new gold-binding domain. The calculated enzyme kinetic parameters k cat , which indicates the turnover rate of substrate to product, and K m (the Michaelis constant), which describes an enzyme's affinity to its substrate, are provided in Table 1.…”

“…[1][2][3][4][5] The recent advances in translating the biomolecular mechanisms into the hybrid materials and system designs promise novel methodologies that may transform some of the authors' engineering approaches. [6][7][8][9][10][11][12][13] One of the major challenges in such systems is to have control at the bio-nanomaterial interface. The biomolecules need to be integrated at the material interfaces without compromising their spatial distribution, organisation and orientation-dependent activity within a desired proximity.…”

“…The biomolecules need to be integrated at the material interfaces without compromising their spatial distribution, organisation and orientation-dependent activity within a desired proximity. 3,4,7,12 Among nature's indispensable repertoire, enzymes, due to their exquisite catalytic features, are certainly one of the most appealing candidates to be utilised as an internal component in next-generation devices. 9,12,14 However, their spatial distribution with the desired orientation on the solid surfaces, operational stability and long-term reuse are among the critical parameters that limit their wide-range integration to functional materials.…”

“…3,4,7,12 Among nature's indispensable repertoire, enzymes, due to their exquisite catalytic features, are certainly one of the most appealing candidates to be utilised as an internal component in next-generation devices. 9,12,14 However, their spatial distribution with the desired orientation on the solid surfaces, operational stability and long-term reuse are among the critical parameters that limit their wide-range integration to functional materials. 2,[10][11][12][13][14][15] There is an urge to develop biological surface functionalisation approaches that will give the ability to control the desired functions at the bio-nanomaterial interfaces with tunability over a multitude of scales.…”

On/Off‐Switchable Zipper‐Like Bioelectronics on a Graphene Interface

“…In the field of switchable bioelectronics, most of the stimuli have been restricted to light, magnetic field, and pH. [7] However, temperature-controlled bioelectronics could provide a promising direct approach to investigate the effect of external temperature on electrocatalytic and bioelectrocatalytic processes on functionalised nanostructured electrodes. [8] Although a number of related studies have been reported for temperature controlled bioelectronics and biocatalytic applications, most of them have focused on biocatalysis using a range of bulk materials such as hydrogels, polymer brushes and polymeric interfaces.…”