Sandwich-Type Enzymatic Fuel Cell Based on a New Electro-Conductive Material - Ion Jelly

Abstract

In the present work, Ion Jelly films based on 1‐ethyl‐3‐methylimidazolium ethylsulfate, with incorporated redox proteins and enzymes were deposited on carbon screen‐printed electrodes (SPEs), and their electrochemical characterization was attained. Ion Jelly synthesis was carried out simultaneously with protein incorporation in its structure, followed by a maturation step under controlled atmosphere (4 days at 4 °C and water activity (aw) of 0.76). The electrochemical response of the material was characterized, and a sandwich‐type fuel cell configuration was subsequently built, consisting of two SPEs containing two independent Ion Jelly discs in the middle; one disc incorporated Desulfovibrio gigas cytochrome c3 and [NiFe]‐hydrogenase, while the other disc contained aldehyde oxidoreductase, constituting the biocathode and bioanode of the cell, respectively. Cell voltage increased with time in the presence of benzaldehyde, in agreement with a successful electronic pathway across the cell and the concomitant aldehyde oxidoreductase enzymatic activity. In the cathodic side assays, hydrogenase showed catalytic activity towards H+ reduction to H2.

Supramolecular Ionic Liquid Gels for Enzyme Entrapment

“…The facile shaping of the gel can be exploited to make thin layers and coatings, and this is anticipated to improve mass transport and activity. Coating electrodes will enable use in bioelectrocatalytic applications, due to the ability of an IL gel to act as a solid electrolyte, as demonstrated by Carvalho et al 75 …”

Electrode Kinetics of Ion Jelly and Ion Sol-Gel Redox Materials on Screen-Printed Electrodes

“…Cyclic voltammetry (CV) assays of IJ or ISG modified SPEs were carried out in the same anaerobic conditions as described in previous work performed with ion jelly [15] inside an anaerobic chamber (O 2 conc. < 0.1 ppm) (MBraun Unilab-Oststeinbek, Germany).…”

“…ISG was previously demonstrated to be stable in water, and while the native conductivity of ISG films is one to two orders of magnitude lower than that of IJ, the opposite happens in swollen films, with conductivity of [omim][TFSI] ISG surpassing that of IJ by one to two orders of magnitude (Figure 2). same anaerobic conditions as described in previous work performed with ion jelly [15] inside an anaerobic chamber (O2 conc. < 0.1 ppm) (MBraun Unilab-Oststeinbek, Germany).…”

“…Ionogels have also been studied as catalytic membranes by loading the material with various types of catalysts. Since some ILs work well in enhancing the activity and stability of enzymes [12,13], some ionogels are an attractive medium for biocatalysis, namely for building electrodes for enzymatic fuel cells or as biosensors [14][15][16].…”

“…Ion jelly (IJ) is a macromolecular gel material that uses gelatin as the solid phase and is obtained by mixing water and hydrophilic ionic liquids [17]. Ionic and hydrogen bonds are established, creating a microenvironment appropriate for biomolecule immobilization and stabilization, with cytochrome c and some oxidoreductases having been used as model enzymes for immobilization in IJ [15,18,19]. Being gelatin-based, IJ can be easily molded into various shapes, such as membranes or fibers [20,21].…”