Magneto‐switchable Electrodes and Electrochemical Systems

Abstract

[a] 1IntroductionChemically modified electrodes [1] have been extensively developed from 1970-80s [2][3][4],m ostly for electrocatalytic applications.E xtending chemicals ystems associated with electrode surfaces to complexb iomolecular assemblies resulted in bioelectrocatalytic systems [5,6] particularly usedi ne lectrochemical biosensors [7][8][9] and biofuel cells [10][11][12].N ew applications required novel adaptive properties of electrochemicals ystems which have been realizedi nm odified electrodes functionalized with various signal-responsive materials [13,14] [29].I n the mosts ophisticated systems, the activity of switchable electrodes was controlled by complexm ulti-enzymes ystems,b eing reversibly activated-inactivated by various patterns of different biochemicals added to solutions [30][31][32],t hus mimickingb iological regulative and adaptive properties.F urther advances in the design of novel bioelectrochemical and bioelectronic systemsw ere achieved with the use of biomolecular-functionalized nano-species (nanoparticles,c arbon nanotubes,e tc.) [33][34][35].T he use of magnetic micro/nano-species( e.g.,n anoparticles,n anorods,n anosheets) [36][37][38][39][40]w as particularly important for the development of novel magneto-switchable electrodes with unique and unusual properties [25-28, 41, 42].Thep resent article overviews shortly various electrochemical systems with switchable features controlled by external magnetic field and basedo nm agnetic micro/ nano-species.A pplying magnetic field to magnetics pecies with redox, electrocatalytic or bioelectrocatalytic properties and moving them arounda llowed their different arrangements on electrode surfaces,t hus changing the electrochemical responses,s witchingt hem ON and OFF and resulting in many interestingf eatures.W hile the exact description of the exemplified systemsc an be found in the original research papers,the presentr ichly illustrated article aims at the concept explanationst os ummarize the fieldd evelopments up to date. 2Lateral TranslocationofM agnetic Micro/NanoSpecies on Electrodes and Electrode ArraysOne of the first examplesofthe magneto-switchable bioelectrochemicals ystems was basedo nalateralt ranslocation of DNA-functionalized magnetic microspheres (super-paramagnetic polystyrene beads,c a. 1 mm, with included Fe 3 O 4 nanoparticles) alonga ne lectrodea rray composed of two conducting areas ("left"a nd "right" electrodes), both with the applied potential capable of oxidizing DNAm olecules [43],F igure1.T he magnetic microspheres chemically modified with DNAo ligomers (GGC CGA CTC ACTG CG CGT CTT CTG TCC CGC Abstract:T his article is an overview of extensive research efforts in many laboratories in the last two decades in the area of magneto-switchable electrochemicals ystems. Electrochemical reactions, including electrocatalytic and bioelectrocatalytic processes,h ave been reversibly activated and inhibited upon physical translocation and reorientation of differentm agnetic micro/nano-species on electrode surfaces,p artic...

Bioelectrocatalytic Electrodes Modified with PQQ‐Glucose Dehydrogenase‐Calmodulin Chimera Switchable by Peptide Signals: Pathway to Generic Bioelectronic Systems Controlled by Biomolecular Inputs

“…Signal‐controlled (bio)electrochemical systems with switchable/tunable activity are essential for assembling bioelectronic, (particularly implantable bioelectronic) systems with adaptable behavior in biological environment. The majority of signal‐controlled electrochemical systems has been based on electrodes chemically modified with stimuli‐responsive materials (usually polymers) sharply changing their properties upon receiving external signals in the form of light irradiation, magnetic field application, temperature change, pH variation, etc. These changes result in activation/inhibition of electrochemical processes at the modified electrode surfaces, predominantly affecting electronic communication between biological molecules (usually enzymes, frequently involving electron‐transfer mediators) and the conducting support, thus switching bioelectrocatalytic processes ON and OFF.…”

Modified Electrodes and Electrochemical Systems Switchable by Temperature Changes

“…The present article overviews achievements in design of modified electrodes and electrochemical systems controlled by temperature changes and sharply switchable between active and inactive electrochemical states by temperature alteration. This review continuous a line of recently published review articles on electrodes and electrochemical systems controlled by magnetic signals [9] and pH changes [10], now extending discussion to thermo-sensitive systems.…”

Electrochemical Behavior of Cytochrome C Immobilized in a Magnetically Induced Mesoporous Framework

“…Electrochemical reactions, including bioelectrocatalytic and electrocatalytic processes, have been reversibly activated and inhibited upon physical translocation and reorientation of different magnetic micro/nano‐species on the electrode surface, particularly using magnetic micro‐and nanoparticles . Recently, the magnetic‐field‐induced orientation of fructose dehydrogenase on iron oxide nanoparticles for enhanced direct electron transfer (DET) has been reported .…”

“…[15] Electrochemical reactions, including bioelectrocatalytic and electrocatalytic processes, have been reversibly activated and inhibited upon physical translocation and reorientation of different magnetic micro/nano-species on the electrode surface, particularly using magnetic micro-and nanoparticles. [16] Recently, the magnetic-field-induced orientation of fructose dehydrogenase on iron oxide nanoparticles for enhanced direct electron transfer (DET) has been reported. [18] In this study, the magnetic interactions between the paramagnetic heme groups of fructose dehydrogenase subunit II and superparamagnetic iron oxide nanoparticles enables a suitable orientation of the enzyme molecule and enhance the rate of DET.…”