Biofuel Cell Controlled by Enzyme Logic Systems

Abstract

An enzyme-based biofuel cell with a pH-switchable oxygen electrode, controlled by enzyme logic operations processing in situ biochemical input signals, has been developed. Two Boolean logic gates (AND/OR) were assembled from enzyme systems to process biochemical signals and to convert them logically into pH-changes of the solution. The cathode used in the biofuel cell was modified with a polymer-brush functionalized with Os-complex redox species operating as relay units to mediate electron transport between the conductive support and soluble laccase biocatalyzing oxygen reduction. The electrochemical activity of the modified electrode was switchable by alteration of the solution pH value. The electrode was electrochemically mute at pH > 5.5, and it was activated for the bioelectrocatalytic oxygen reduction at pH < 4.5. The sharp transition between the inactive and active states was used to control the electrode activity by external enzymatic systems operating as logic switches in the system. The enzyme logic systems were decreasing the pH value upon appropriate combinations of the biochemical signals corresponding to the AND/OR Boolean logic. Then the pH-switchable electrode was activated for the oxygen reduction, and the entire biofuel cell was switched ON. The biofuel cell was also switched OFF by another biochemical signal which resets the pH value to the original neutral value. The present biofuel cell is the first prototype of a future implantable biofuel cell controlled by complex biochemical reactions to deliver power on-demand responding in a logical way to the physiological needs.

Control of Noise in Chemical and Biochemical Information Processing

“…Well developed research, not reviewed here, addresses the interfacing of biomolecular logic with "smart" signal-responsive [16,59,74,101,[195][196][197][198][199][200][201][202][203][204][205] materials and with electrodes and bioelectronic devices. [16,[206][207][208][209][210][211][212] The interfacing/transduction of (bio)chemical signals to electronic ones, can also incorporate a filtering "sigmoidal" property, as has been recently experimentally demonstrated. [16] The above discussion reveals that while (bio)chemical filtering is a desirable property for gates and network elements, its direct experimental realization has thus far been quite limited.…”

Heterologous laccase production and its role in industrial applications

“…As a fact, laccases can be adopted (1) to bleach textiles; 12 (2) to eliminate undesirable phenolics responsible for the browning, haze formation and turbidity development in clear fruit juice, beer and wine; 13 (3) to bleach wood pulp; 14 (4) to synthesize various functional organic compounds such as drug, dyes; 15,16 (5) to produce various polymers; 17 (6) to detect molecules in biosensor devices; 18 (7) to produce power in biofuel cells; 19 (8) and to dye hair. 20 As far as bioremediation is concerning, laccases may be applied to decolorize textile effluents; 21 to degrade plastic waste having olefin units; 20 to eliminate odor emitted from places such as garbage disposal sites, livestock farms, or pulp mills; 20 to remove phenolic compounds from olive concentration is required for the production of active laccase at a post-translational step in a heterologous host.…”

Synthesis of a New Cathode Redox Polymer for High Performance in Biofuel Cells

“…27,[38][39][40][41][42] At the cathode, the electrons were transferred from the electode Os(III), Os(II) to bilirubin oxidase (extracted from Myrothecium verrucaria) which catalyzed O 2 to H 2 O (Eq. (2)):…”