High performance glucose/O2 biofuel cell: effect of utilizing purified laccase with anthracene-modified multi-walled carbon nanotubes

pre-printLaccase, a blue multicopper oxidoreductase enzyme, is a robust enzyme that catalyzes the reduction of oxygen to water and has been shown previously to perform improved direct electron transfer in a biocathode when mixed with anthracene-modified multi-walled carbon nanotubes. Previous cathode construction used crude laccase enzyme isolated as a brown cell extract powder containing both active and inactive proteins. Purification of this enzyme, yielding a blue solution, resulted in greatly improved enzyme activity and removed insulating protein that competed for docking space in this cathodic system. Cyclic voltammetry of the purified biocathodes showed a background subtracted limiting current density of 1.84 (±0.05) mA/cm2 in a stationary air-saturated system. Galvanostatic and potentiostatic stability experiments show that the biocathode maintains up to 75% and 80% of the original voltage and current respectively over 24 hours of constant operation. Inclusion of the biocathode in a glucose/O2 biofuel cell using a mediated glucose oxidase (GOx) anode produced maximum current and power densities of 1.28 (±0.18) mA/cm2 and 281 (±50) μW/cm2 at 25◦C and 1.80 (±0.06) mA/cm2 and 381 (±33) μW/cm2 at 37◦C, respectively. Enzymatic efficiency of this glucose/O2 enzymatic fuel cell is among the highest reported for a glucose/O2 enzymatic fuel cell

A new mathematical modelling using Homotopyperturbation method to solve nonlinear equations in enzymatic glucose fuel cells.

For the first time a mathematical modelling of the enzymatic glucose membraneless fuel cell with direct electron transfer has been reported. The niche of this mathematical modelling is the description of the new Homotopy perturbation method to solve the nonlinear differential equations that describes glucose concentration and hydrogen ions respectively. The analytical results of an enzymatic fuel cell should be used, while developing fuel cell, to estimate its various kinetic parameters to attain the highest power value. Our analytical results are compared with limiting case results and satisfactory agreement is noted. The influence of parameters on the concentrations are discusse

Self-powered wireless carbohydrate/oxygen sensitive biodevice based on radio signal transmission

peer-reviewedHere for the first time, we detail self-contained (wireless and self-powered) biodevices with wireless signal transmission. Specifically, we demonstrate the operation of self-sustained carbohydrate and oxygen sensitive biodevices, consisting of a wireless electronic unit, radio transmitter and separate sensing bioelectrodes, supplied with electrical energy from a combined multi-enzyme fuel cell generating sufficient current at required voltage to power the electronics. A carbohydrate/oxygen enzymatic fuel cell was assembled by comparing the performance of a range of different bioelectrodes followed by selection of the most suitable, stable combination. Carbohydrates (viz. lactose for the demonstration) and oxygen were also chosen as bioanalytes, being important biomarkers, to demonstrate the operation of the self-contained biosensing device, employing enzyme-modified bioelectrodes to enable the actual sensing. A wireless electronic unit, consisting of a micropotentiostat, an energy harvesting module (voltage amplifier together with a capacitor), and a radio microchip, were designed to enable the biofuel cell to be used as a power supply for managing the sensing devices and for wireless data transmission. The electronic system used required current and voltages greater than 44 mu A and 0.57 V, respectively to operate; which the biofuel cell was capable of providing, when placed in a carbohydrate and oxygen containing buffer. In addition, a USB based receiver and computer software were employed for proof-of concept tests of the developed biodevices. Operation of bench-top prototypes was demonstrated in buffers containing different concentrations of the analytes, showcasing that the variation in response of both carbohydrate and oxygen biosensors could be monitored wirelessly in real-time as analyte concentrations in buffers were changed, using only an enzymatic fuel cell as a power supply.PUBLISHEDpeer-reviewe

Stability of proton exchange membranes in phosphate buffer for enzymatic fuel cell application: hydration, conductivity and mechanical properties

Proton-conducting ionomers are widespread materials for application in electrochemical energy storage devices. However, their properties depend strongly on operating conditions. In bio-fuel cells with a separator membrane, the swelling behavior as well as the conductivity need to be optimized with regard to the use of buffer solutions for the stability of the enzyme catalyst. This work presents a study of the hydrolytic stability, conductivity and mechanical behavior of different proton exchange membranes based on sulfonated poly(ether ether ketone) (SPEEK) and sulfonated poly(phenyl sulfone) (SPPSU) ionomers in phosphate buffer solution. The results show that the membrane stability can be adapted by changing the casting solvent (DMSO, water or ethanol) and procedures, including a crosslinking heat treatment, or by blending the two ionomers. A comparison with Nafion(TM) shows the different behavior of this ionomer versus SPEEK membranes

Transparent and flexible, nanostructured and mediatorless glucose/oxygen enzymatic fuel cells

Here we detail transparent, flexible, nanostructured, membrane-less and mediator-free glucose/oxygen enzymatic fuel cells, which can be reproducibly fabricated with industrial scale throughput. The electrodes were built on a biocompatible flexible polymer, while nanoimprint lithography was used for their nanostructuring. The electrodes were covered with gold, their surfaces were visualised using scanning electron and atomic force microscopies, and they were also studied spectrophotometrically and electrochemically. The enzymatic fuel cells were fabricated following our previous reports on membrane-less and mediator-free biodevices in which cellobiose dehydrogenase and bilirubin oxidase were used as anodic and cathodic biocatalysts, respectively. The following average characteristics of transparent and flexible biodevices operating in glucose and chloride containing neutral buffers were registered: 0.63 V open-circuit voltage, and 0.6 mu W cm(-2) maximal power density at a cell voltage of 0.35 V. A transparent and flexible enzymatic fuel cell could still deliver at least 0.5 mu W cm(-2) after 12 h of continuous operation. Thus, such biodevices can potentially be used as self-powered biosensors or electric power sources for smart electronic contact lenses. (C) 2015 Elsevier B.V. All rights reserved

Kinetic study of homogeneously mediated electrode reactions in glucose-based biofuel cells.

The use of biofuel cells (BFC) is a promising approach to generate electricity. BFC can be successfully applied to achieve long-term autonomous operation of miniaturized implantable Body-Area-Network (BAN) devices. BAN devices are important for the development of future healthcare technologies. Glucose-based enzymatic BFC are a good option to power BAN devices due to the high availability of the fuel (glucose) in body fluids. Moreover, it shows excellent catalytic selectivity and good chemical safety. In this paper, the design of a glucose-based enzymatic BFC demonstrator is described and the performance of both the individual electrodes and the complete cell is evaluated. The measured maximum power output of the designed BFC-demonstrator was 5.8 µWcm-2. Additionally, the kinetics of the detailed energy conversion processes, occurring inside the BFC system, have been investigated from both an experimental and theoretical point of view. The proposed model describes the glucose oxidation at the anode of a BFC and includes the diffusion for all (electro-) chemically active species. The modeling results are qualitatively and quantitatively in good agreement with the experimental results

Biofuel cell based on microscale nanostructured electrodes with inductive coupling to rat brain neurons.

Miniature, self-contained biodevices powered by biofuel cells may enable a new generation of implantable, wireless, minimally invasive neural interfaces for neurophysiological in vivo studies and for clinical applications. Here we report on the fabrication of a direct electron transfer based glucose/oxygen enzymatic fuel cell (EFC) from genuinely three-dimensional (3D) nanostructured microscale gold electrodes, modified with suitable biocatalysts. We show that the process underlying the simple fabrication method of 3D nanostructured electrodes is based on an electrochemically driven transformation of physically deposited gold nanoparticles. We experimentally demonstrate that mediator-, cofactor-, and membrane-less EFCs do operate in cerebrospinal fluid and in the brain of a rat, producing amounts of electrical power sufficient to drive a self-contained biodevice, viz. 7 μW cm(-2) in vitro and 2 μW cm(-2) in vivo at an operating voltage of 0.4 V. Last but not least, we also demonstrate an inductive coupling between 3D nanobioelectrodes and living neurons

Characteristics of Glucose Oxidase Gene (GGOx) from Aspergillus niger IPBCC 08.610

Glucose oxidase is used in various industries for the development of enzymatic fuel cell. Based on prior studies, this compound is sourced from the local isolates of Aspergillus niger IPBCC 08.610, although investigations on the encoding gene have not been conducted. The purpose of this research, therefore, is to identify and characterized the gene responsible for encoding glucose oxidase, in the aspect of sequence, length, and restriction patterns. This experiment involved the amplification of genomic DNA using specific primers for gene recognition, which was followed by the restriction technique with EcoRI and PstI endonucleases. Furthermore, the gene is inserted into vector pGEM®T-Easy and transformed into competent E. coli DH5α cells, in an attempt to perform sequencing. The glucose oxidase gene from A. niger IPBCC 08.610 was confirmed to possess a size of 1848 bp, and a GC content of 57.8%, with a possibility of restriction into two fragments of size 908 bp and 980 bp, using the EcoRI restriction