Use of PEDOT:PSS/Graphene/Nafion Composite in Biosensors Based on Acetic Acid Bacteria.

Yulia Plekhanova,Sergei Tarasov,Anatoly Reshetilov

doi:10.3390/bios11090332

Abstract

Immobilization of the biocomponent is one of the most important stages in the development of microbial biosensors. In this study, we examined the electrochemical properties of a novel PEDOT:PSS/graphene/Nafion composite used to immobilize Gluconobacter oxydans bacterial cells on the surface of a graphite screen-printed electrode. Bioelectrode responses to glucose in the presence of a redox mediator 2,6-dichlorophenolindophenol were studied. The presence of graphene in the composite reduced the negative effect of PEDOT:PSS on cells and improved its conductivity. The use of Nafion enabled maintaining the activity of acetic acid bacteria at the original level for 120 days. The sensitivity of the bioelectrode based on G. oxydans/PEDOT:PSS/graphene/Nafion composite was shown to be 22 μA × mM−1 × cm−2 within the linear range of glucose concentrations. The developed composite can be used both in designing bioelectrochemical microbial devices and in biotechnology productions for long-term immobilization of microorganisms.

Highlights

Immobilization of cells is an essential step in developing bioelectrodes for biosensors and biofuel cells [1]
Using two electrochemical methods, we showed that cells were reliably immobilized on the electrode surface and that addition of glucose led to electron transfer and an increasTe hofucsu,rruesnitsnign tthwe osyestleemc.trochemical methods, we showed that cells were r bilized on the electrode surface and that addition of glucose led to electro Biosensors 2021, 11, x FOR PEER REV3IaE.2nW
CTohnucs,luthseiroenposrted study proposes a novel conducting composite for the immobiwFliziigtahtuigorrneTapoh1hf0ue.bsnaL,ecotteehnnrgeaiab-lrtleeecserpmlilnoscrosrtetneaadsbtihnieslgittsutyuhdreofyaafcnSepaPloryEofti/gpcParoaEl pssDiehgOisnteaaTle:onPlefoScttShvre/oegdblreicaosops.enhTnedshoneureuca/sNnteidnaodfgfieoPccnrEoe/DamGsOi.npTog:oxPtsyShidSetaenfsobrioths tctrhiaoatrnigoenotfroafbngsaflceurtceroerssiiaesltiancnectelhliesnmothneeamtshueearsinusruginrcgfealslcy,es1teommfM.gTr.haepahppitliecaetiloenctorfoNdaefiso.nTprheeseruvsees of PE graphene enables increasing the analytical signal of the biosensor and d 4c.hCarogneclturasniosnfesr resistance in the measuring system

Summary

Introduction

Immobilization of cells is an essential step in developing bioelectrodes for biosensors and biofuel cells [1]. Efficient charge transfer from bacterial cells to the electrode surface requires a tight contact [2]. Immobilization can enhance the stability of microbial cells, allow continuous process operation, protect the bacteria from high pollutant concentrations and improve the rate of charge transfer in the system. Immobilization of cells into conducting gels enables the formation of electroactive biofilms. Electroactive bacteria are encapsulated into a conductive material to constitute a bioelectrode [6]. A wide range of matrices, including chitosan, pectin, gelatin, polyvinyl alcohol, agar, alginate, various silica gels, is used to immobilize biological species [7]. These materials are not characterized by high conductivities, which reduce the efficiency of bioelectrochemical devices based on them

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Conclusion