An Enzymatic Ethanol Biosensor and Ethanol/Air Biofuel Cell Using Liquid-Crystalline Cubic Phases as Hosting Matrices to Co-Entrap Enzymes and Mediators

Abstract

In this study, liquid-crystalline lipidic cubic phases (LCPs) formed by monoolein (MO) were used as hosting matrices to co-entrap enzymes and mediators to fabricate enzyme electrodes for biosensors and enzymatic biofuel cells (BFCs). An ethanol dehydrogenase (ADH)-based bioelectrode was fabricated by co-immobilizing ADH and electrocatalyst, toluidine blue (TB) into MO to form doped LCPs on glassy carbon substrate electrode. The prepared bioelectrode was used for ethanol sensing and bioanode of ethanol/air BFC. The constructed ethanol biosensor displays good linear concentration range from 0 to 15.6 mM with a detection limit of 0.09 mM and was applied for ethanol detection in human serum with satisfactory results. To construct an ethanol/air BFC, a biocathode for oxygen reduction was fabricated by co-immobilizing laccase and redox mediator, 2, 2 -azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) into MO to form doped LCPs on glassy carbon substrate electrode. The performances of the constructed ethanol/air BFC were characterized in buffer solution and red wine, respectively. The open circuit voltage (OCV) and maximum power density of the ethanol/air BFC are 0.53 V and 12.0 μWcm −2 at 0.36 V in buffer solution, and 0.42 V and 2.78 μW cm −2 at 0.26 V in red wine, respectively.

Ethanol Biofuel Cells: Hybrid Catalytic Cascades as a Tool for Biosensor Devices

“…The ethanol detection limit was 0.10 mM. These values were comparable to data achieved with other applied methods for self-powered ethanol biosensors [ 31 , 78 ].…”

“…Gao et al proposed another self-powered ethanol biosensor [ 78 ]. To construct the bioelectrode, the authors used liquid-crystalline lipidic cubic phases (LCPs) composed of monoolein (MO) as a hosting matrix to co-entrap ADH and the electrocatalyst toluidine blue (TB).…”

“…The authors employed the system to detect ethanol in human serum with good reproducibility. An investigation into the performance of the ethanol/air EBFC by power density tests provided an OCV and maximum power density of 0.53 V and 12.0 μWcm −2 , respectively [ 78 ].…”

Tackling the Challenges of Enzymatic (Bio)Fuel Cells

“…Sol-gel based methods have been frequently reported to entrap enzymes with high activity and stability [420][421][422][423][424] . Entrapping redox enzymes into membrane-like matrices, such as lipid, agarose and DNA-hydrogel, which can mimic the natural environment of enzymes, retains enzymes in functionally active forms [425][426][427][428] . However, such matrices usually suffer from poor conductivity, and cannot be used MWCNT for over 60 days' continuous measurement, with more than 70% of the initial current retained upon storage for six months.…”

A Glucose-Responsive Enzymatic Electrode on Carbon Nanodots for Glucose Biosensor and Glucose/Air Biofuel Cell

“…From this Table, it can be seen that the determination results are good agreement with the results provided by the hospital and the RSD values are smaller than 2.97%, indicating that the proposed glucose biosensor displays good accuracy and repeatability in complex samples and therefore shows potentially practical applications. It has been attracted much attention to develop NAD + -dependent dehydrogenase based bioanodes for constructing BFCs because more than 300 dehydrogenases have been known today and therefore different substrates of dehydrogenases can be employed for biofuels [17] [18] [19]. Glucose, as a most active fuel of enzymatic BFCs, is also a common ambient fuel which exists widely in human, animals, plants, various foods.…”