A Biofuel Cell Based on Biocatalytic Reactions of Glucose on Both Anode and Cathode Electrodes

Biofuel cells based on electrocatalytic oxidation of NADH and reduction of H₂O₂ have been prepared using carbon fiber electrodes functionalized with graphene nano‐flakes. The electrochemical oxidation of NADH was catalyzed by Meldola's blue (MB), while the reduction of H₂O₂ was catalyzed by hemin, both catalysts were adsorbed on the graphene flakes due to their π‐π staking. In the next set of experiments, the MB‐ and hemin‐electrodes were additionally modified with glucose dehydrogenase (GDH) and glucose oxidase (GOx), respectively. The enzyme catalyzed reactions in the presence of glucose, NAD⁺ and O₂ resulted in the production of NADH and H₂O₂ in situ. The produced NADH and H₂O₂ were oxidized and reduced, respectively, at the bioelectrocatalytic electrodes, thus producing voltage and current generated by the biofuel cell. The enzyme‐based biofuel cells operated in a human serum solution modelling an implantable device powered from the natural biofluid. Finally, two enzyme‐based biofuel cell connected in series and operating in the serum solution produced electrical power sufficient for activation of an electronic watch used as an example device.     

Implanted biofuel cell operating in a living snail

Implantable biofuel cells have been suggested as sustainable micropower sources operating in living organisms, but such bioelectronic systems are still exotic and very challenging to design. Very few examples of abiotic and enzyme-based biofuel cells operating in animals in vivo have been reported. Implantation of biocatalytic electrodes and extraction of electrical power from small living creatures is even more difficult and has not been achieved to date. Here we report on the first implanted biofuel cell continuously operating in a snail and producing electrical power over a long period of time using physiologically produced glucose as a fuel. The "electrified" snail, being a biotechnological living "device", was able to regenerate glucose consumed by biocatalytic electrodes, upon appropriate feeding and relaxing, and then produce a new "portion" of electrical energy. The snail with the implanted biofuel cell will be able to operate in a natural environment, producing sustainable electrical micropower for activating various bioelectronic devices.     

Wireless Information Transmission System Powered by an Abiotic Biofuel Cell Implanted in an Orange

An “abiotic” biofuel cell composed of catalytic electrodes modified with inorganic nanoparticles (NPs) deposited on carbon black (CB) was used to activate a wireless information transmission system. The cathode and anode were made of carbon paper modified with Pt‐NPs/CB and buckypaper modified with Au₈₀Pt₂₀‐NPs/CB, respectively. The cathode/anode pair was implanted in orange pulp extracting power from its content (glucose and fructose in the juice). The open circuit voltage, V_oc, short circuit current density, j_sc, and maximum power produced by the biofuel cell, P_max, were found as 0.36 V, 1.3 mA cm^?2 and 182 µW, respectively. The voltage produced by the biofuel cell was amplified with an energy harvesting circuit and applied to a wireless transmitter. The present study continues the research line where different implantable biofuel cells are used for activation of electronic devices.     

Biofuel cell controlled by enzyme logic network — Approaching physiologically regulated devices

A “smart” biofuel cell switchable ON and OFF upon application of several chemical signals processed by an enzyme logic network was designed. The biocomputing system performing logic operations on the input signals was composed of four enzymes: alcohol dehydrogenase (ADH), amyloglucosidase (AGS), invertase (INV) and glucose dehydrogenase (GDH). These enzymes were activated by different combinations of chemical input signals: NADH, acetaldehyde, maltose and sucrose. The sequence of biochemical reactions catalyzed by the enzymes models a logic network composed of concatenated AND/OR gates. Upon application of specific “successful” patterns of the chemical input signals, the cascade of biochemical reactions resulted in the formation of gluconic acid, thus producing acidic pH in the solution. This resulted in the activation of a pH-sensitive redox-polymer-modified cathode in the biofuel cell, thus, switching ON the entire cell and dramatically increasing its power output. Application of another chemical signal (urea in the presence of urease) resulted in the return to the initial neutral pH value, when the O₂-reducing cathode and the entire cell are in the mute state. The reversible activation–inactivation of the biofuel cell was controlled by the enzymatic reactions logically processing a number of chemical input signals applied in different combinations. The studied biofuel cell exemplifies a new kind of bioelectronic device where the bioelectronic function is controlled by a biocomputing system. Such devices will provide a new dimension in bioelectronics and biocomputing benefiting from the integration of both concepts.     

Guanine/Ionic Liquid Derived Ordered Mesoporous Carbon Decorated with AuNPs as Efficient NADH Biosensor and Suitable Platform for Enzymes Immobilization and Biofuel Cell Design

Guanine‐ionic liquid derived ordered mesoporous carbon (GIOMC) decorated with gold nanoparticles was used as electrocatalyste for NADH oxidation and electrochemical platform for immobilization of glucose dehydrogenase (GDH) enzyme. The resulting GIOMC/AuNPs on the glassy carbon electrode can be used as novel redox‐mediator free for NADH sensing and this integrated system (GIOMC/AuNPs/GDH) shows excellent electrocatalytic activity toward glucose oxidation. Furthermore, the ionic liquid derived ordered mesoporous carbon derivate with Ph‐SO₃H (IOMC‐PhSO₃H) decorated with AuNPs has been developed to bilirubin oxidase enzyme (BOD) immobilization and the GC/IOMC‐PhSO₃H/BOD integrated system shows excellent bioelectrocatalytic activity toward oxygen reduction reaction. The proposed mesostructured platforms decorated by AuNPs have been developed to enhance mass transfer and charge transfer from biocatalyst to electrode, leading these bioanode and biocathode used for biofuel cell assembly. Integration designed bioanode and biocathode yielding a membrane‐less glucose/O₂ biofuel cell with power density of 33 (mW.cm⁻²) at 257 mV. The open circuit voltage of this biofuel cell and maximum produced current density were 508 mV and 0.252 (mA.cm⁻²) respectively.     

Concentric glucose/O2 biofuel cell

A concentric glucose/O₂ biofuel cell has been developed. The device is constituted of two carbon tubular electrodes, one in the other, and combines glucose electrooxidation at the anode and oxygen electroreduction at the cathode. The anodic catalyst is glucose oxidase co-immobilized with the mediator 8-hydroxyquinoline-5-sulfonic acid hydrate, and the cathodic catalyst is bilirubin oxidase co-immobilized with the mediator 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonate) diammonium salt. Both enzymes and mediators are entrapped at the surface of the tubular electrodes by an electrogenerated polypyrrole polymer. The originality of the concentric configuration is to compartmentalize the anode and cathode electrodes and to supply dissolved oxygen separate from the electrolyte in order to avoid secondary reactions. The dissolved oxygen circulates through the inside of the cathode tube and diffuses from the inner to the external surface of the tube to react directly with the immobilized bilirubin oxidase. The assembled biofuel cell is studied at 37 °C in phosphate buffer pH 7.4. We show the influence of the thickness of the polypyrrole polymer on the electrochemical activity of the biocathodes. We also demonstrate the effect of the chemical reticulation of the enzymes by glutaraldehyde within the polymer on the performances of the bioelectrodes. The maximum power density delivered by the assembled glucose/O₂ biofuel cell reaches 42 μW cm⁻², evaluated from the geometric area of the electrodes, at a cell voltage of 0.30 V with 10 mM glucose. The results demonstrate that the concentric design of the BFC based on compartmented electrodes is a promising architecture for further development of micro electronic devices.     

A microfluidic glucose biofuel cell to generate micropower from enzymes at ambient temperature

A Y-shaped microfluidic channel is applied for the first time to the construction of a glucose/O₂ biofuel cell, based on both laminar flow and biological enzyme strategies. During operation, the fuel and oxidant streams flow parallel at gold electrode surfaces without convective mixing. At the anode, the glucose oxidation is performed by the enzyme glucose oxidase whereas at the cathode, the oxygen is reduced by the enzyme laccase, in the presence of specific redox mediators. Such cell design protects the anode from an interfering parasite reaction of O₂ at the anode and offers the advantage of using different streams of oxidant and fuel for optimal performance of the enzymes. Electrochemical characterizations of the device show the influence of the flow rate on the output potential and current density. The maximum power density delivered by the assembled biofuel cell reached 110 μW cm^?2 at 0.3 V with 10 mM glucose at 23 °C. The microfluidic approach reported here demonstrates the feasibility of advanced microfabrication techniques to build an efficient microfluidic glucose/O₂ biofuel cell device.     

Biofuel Cell Operating in Vivo in Rat

Biocatalytic electrodes made of buckypaper were modified with PQQ‐dependent glucose dehydrogenase on the anode and with laccase on the cathode. The enzyme modified electrodes were assembled in a biofuel cell which was first characterized in human serum solution and then the electrodes were placed onto exposed rat cremaster tissue. Glucose and oxygen dissolved in blood were used as the fuel and oxidizer, respectively, for the implanted biofuel cell operation. The steady‐state open circuitry voltage of 140±30 mV and short circuitry current of 10±3 µA (current density ca. 5 µA cm^?2 based on the geometrical electrode area of 2 cm²) were achieved in the in vivo operating biofuel cell. Future applications of implanted biofuel cells for powering of biomedical and sensor devices are discussed.     

Study on Glucose Biofuel Cells Using an Electrochemical Noise Device

An electrochemical noise (ECN) device was utilized for the first time to study and characterize a glucose/O₂ membraneless biofuel cell (BFC) and a monopolar glucose BFC. In the glucose/O₂ membraneless BFC, ferrocene (Fc) and glucose oxidase (GOD) were immobilized on a multiwalled carbon nanotubes (MWCNTs)/Au electrode with a gelatin film at the anode; and laccase (Lac) and an electron mediator, 2,2′‐azinobis (3‐ethylbenzothiazoline‐6‐sulfonate) diammonium salt (ABTS), were immobilized on a MWCNTs/Au electrode with polypyrrole at the cathode. This BFC was performed in a stirred acetate buffer solution (pH 5.0) containing 40 mmol/L glucose in air, with a maximum power density of 8 μW/cm², an open‐circuit cell voltage of 0.29 V, and a short‐circuit current density of 85 μA/cm², respectively. The cell current at the load of 100 kΩ retained 78.9% of the initial value after continuous discharging for 15 h in a stirred acetate buffer solution (pH 5.0) containing 40 mmol/L glucose in air. The performance decrease of the BFC resulted mainly from the leakage of the ABTS mediator immobilized at the cathode, as revealed by the two‐channel quartz crystal microbalance technique. In addition, a monopolar glucose BFC was performed with the same anode as that in the glucose/O₂ membraneless BFC in a stirred phosphate buffer solution (pH 7.0) containing 40 mmol/L glucose, and a carbon cathode in Nafion‐membrane‐isolated acidic KMnO₄, with a maximum power density of 115 μW/cm², an open‐circuit cell voltage of 1.24 V, and a short‐circuit current density of 202 μA/cm², respectively, which are superior to those of the glucose/O₂ membraneless BFC. A modification of the anode with MWCNTs for the monopolar glucose BFC increased the maximum power density by a factor of 1.8. The ECN device is highly recommended as a convenient, real‐time and sensitive technique for BFC studies.     

Biofuel Cell Based on Anode and Cathode Modified by Glucose Oxidase

A single compartment biofuel cell (BFC) based on an anode and a cathode powered by the same fuel glucose is reported. Glucose oxidase (GOx) from Aspergillus niger was applied as a glucose consuming biocatalyst for both anode and cathode of the BFC. The 5‐amino‐1,10‐phenanthroline modified graphite rod electrode (GRE) with cross‐linked GOx was used as the bioanode, and the GRE with co‐immobilised horseradish peroxidase and GOx was exploited as the biocathode of the BFC. The open‐circuit voltage of the designed BFC exceeded 450 mV and a maximal power density of 3.5 µW/cm² was registered at a cell voltage of 300 mV.     

4-巯基苯甲酸功能化纳米金粒子固定葡萄糖氧化酶/漆酶基燃料电池性能

以4-巯基苯甲酸修饰纳米金粒子作为固酶载体和导电基体构建了新型纳米结构固酶葡萄糖/O₂燃料电池,其制备简单,长期使用性能稳定。利用纳米金粒子通过表面修饰基团和酶分子活性中心附近疏水结合位之间的相互作用固定葡萄糖氧化酶(GO_x)和漆酶(Lac)分子,分别制备了固酶阳极-4-巯基苯甲酸功能化纳米金粒子固定葡萄糖氧化酶修饰金盘电极GO_x/4-MBA@GNP/Au和固酶阴极-4-巯基苯甲酸功能化纳米金粒子固定漆酶修饰金盘电极Lac/4-MBA@GNP/Au。电化学实验结果表明,两种电极在不引入任何外加电子中介的条件下,均可以实现酶活性中心-纳米金粒子之间的直接电子迁移,而且具有较快的催化反应能力(固酶阳极和阴极的转化速率分别为1.3和0.5 s^-1;催化葡萄糖氧化和氧气还原的起始电位分别为-0.23和0.76 V)。评估了固酶阳极和阴极组装成的纳米结构固酶葡萄糖/O₂燃料电池的能量输出性能。该燃料电池在没有Nafion薄膜和阳极无N₂气保护下,开路电压和最大输出能量密度分别可达0.56 V和760.0 μW/cm²,使用一周后输出能量密度仍然可以达到最初值的~88%。进一步测试结果显示,该燃料电池呈现出与游离漆酶类似的pH依赖关系和热稳定性,这些实验结果均暗示:影响整个酶燃料电池性能的关键在于漆酶基阴极催化氧还原的过程。此外,这种燃料电池的性能虽然受到共存干扰物抗坏血酸的影响,但在人类血清中测试结果显示其仍然具有较高的输出能量密度(132.0 μW/cm²,开路电压0.40 V)。本文研究结果给出了设计高性能葡萄糖/O₂燃料电池的新思路,同时也为研究固酶燃料电池的构效关系提供了实验依据和有价值的启示。     

An implantable biofuel cell for a live insect

A biofuel cell incorporating a bienzymatic trehalase|glucose oxidase trehalose anode and a bilirubin oxidase dioxygen cathode using Os complexes grafted to a polymeric backbone as electron relays was designed and constructed. The specific power densities of the biofuel cell implanted in a female Blaberus discoidalis through incisions into its abdomen yielded maximum values of ca. 55 μW/cm(2) at 0.2 V that decreased by only ca. 5% after ca. 2.5 h of operation.     

A promising dehydrogenase-based bioanode for a glucose biosensor and glucose/O2 biofuel cell

A new type of dehydrogenase-based amperometric glucose biosensor was constructed using glucose dehydrogenase (GDH) which was immobilized on the edge-plane pyrolytic graphite (EPPG) electrode modified with poly(phenosafranin)-functionalized single-walled carbon nanotubes (PPS-SWCNTs). The PPS-SWCNT-modified EPPG electrode was prepared by electropolymerization of phenosafranin on the EPPG electrode which had been previously coated with SWCNTs. The performance of the GDH/PPS-SWCNT/EPPG bioanode was evaluated using cyclic voltammetry and amperometry in the presence of glucose. The GDH/PPS-SWCNT/EPPG electrode possesses promising characteristics as a glucose sensor: a wide linear dynamic range of 50 to 700 μM, low detection limit of 0.3 μM, fast response time (1-2 s), high sensitivity (96.5 μA cm(-2) mM(-1)), and anti-interference and anti-fouling abilities. Moreover, the performance of the GDH/PPS-SWCNT/EPPG bioanode was tested in a glucose/O(2) biofuel cell. The maximum power density delivered by the assembled glucose/O(2) biofuel cell could reach 64.0 μW cm(-2) at a cell voltage of 0.3 V with 40 mM glucose.     

Deactivation of bilirubin oxidase by a product of the reaction of urate and O2

The "wired" bilirubin oxidase (BOD) bioelectrocatalyst is superior to pure platinum as an electrocatalyst of the four-electron electroreduction of O(2) to water. Not only is its overpotential for O(2) reduction lower, but unlike platinum, it is not affected by organic compounds like glucose. The "wired" BOD-coated carbon cathode operates for >1 week at 37 degrees C in a glucose-containing physiological buffer solution. One of its key applications would be in a glucose-O(2) biofuel cell, which would operate in living tissues. The cathode is, however, short-lived in serum, losing its electrocatalytic activity in a few hours. Here we show that the damaging serum component is a product of the reaction of urate and dissolved oxygen. Exclusion of urate, by application of Nafion film on the cathode, improves the stability in serum.     

An easy compartment-less biofuel cell construction based on the physical co-inclusion of enzyme and mediator redox within pressed graphite discs

We report on the easy and fast immobilization of glucose oxidase (GOD) and laccase by mechanical compression with graphite particles to form disc electrodes. The electrical wiring of GOD and laccase was efficiently carried out by their co-inclusion with ferrocene (Fc) and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonate) diammonium salt (ABTS) respectively. A glucose/air compartment-less biofuel cell was constructed based on the association of GOD-ferrocene-graphite disc and laccase-ABTS – graphite disc electrodes as bioanode and biocathode respectively. Such biofuel cell yielded a power density of 23 μW cm^?2 at 0.33 V as well as an open-circuit voltage and a short-circuit current of 0.63 V and 166 μA, respectively.     

Preparation of Close‐Packed Silver Nanoparticles on Graphene to Improve the Enzyme Immobilization and Electron Transfer at Electrode in Glucose/O2 Biofuel Cell

In this study, chemical reduced graphene‐silver nanoparticles hybrid (AgNPs @CR‐GO ) with close‐packed AgNPs structure was used as a conductive matrix to adsorb enzyme and facilitate the electron transfer between immobilized enzyme and electrode. A facile route to prepare AgNPs @CR‐GO was designed involving in β ‐cyclodextrin (β ‐CD ) as reducing and stabilizing agent. The morphologies of AgNPs were regulated and controlled by various experimental factors. To fabricate the bioelectrode, AgNPs @CR‐GO was modified on glassy carbon electrode followed by immobilization of glucose oxidase (GOx ) or laccase. It was demonstrated by electrochemical testing that the electrode with close‐packed AgNPs provided high GOx loading (Γ =4.80 × 10⁻¹⁰ mol•cm⁻²) and fast electron transfer rate (k _s=5.76 s⁻¹). By employing GOx based‐electrode as anode and laccase based‐electrode as cathode, the assembled enzymatic biofuel cell exhibited a maximum power density of 77.437 μW •cm⁻² and an open‐circuit voltage of 0.705 V.     

A glucose/O2 biofuel cell base on nanographene platelet-modified electrodes

This study demonstrated a novel nanographene platelets (NGPs)-based glucose/O₂ biofuel cell (BFC) with the glucose oxidase (GOD) as the anodic biocatalysts and the laccase as the cathodic biocatalysts. The GOD/NGPs-modified electrode exhibited good catalytic activity towards glucose oxidation and the laccase/NGPs-modified electrode exhibited good catalytic activity towards O₂ electroreduction. The maximum power density was ca. 57.8 μW cm^? 2 for the assembled glucose/O₂ NGPs-based BFC. These results indicated that the NGPs were very useful for the future development of novel carbon-based nanomaterials BFC device.     

Amperometric Multienzyme Sensor for Determination of D-Glucono-δ-Lactone

Abstract

An amperometric enzyme sensor for the determination of gluconolactone in glucose-containing samples has been developed. The interfering glucose is eliminated by an outer anti-interference layer containing hexokinase, whilst the gluconolactone reaches a glucose de-hydrogenase-glucose oxidase layer, where it is converted into glucose (by glucose dehydrogenase) and then transformed by glucose oxidase, the associated oxygen consumption can be measured at the electrode. Gluconolactone is determined over the concentration range, 0.02–1 mmo1/1, with a toleration of glucose concentration up to 2 mmo1/1.     

The Application of Engineered Glucose Dehydrogenase to a Direct Electron–Transfer‐Type Continuous Glucose Monitoring System and a Compartmentless Biofuel Cell

Abstract

Continuous glucose monitoring (CGM) is expected to become an ideal way to monitor glycemic levels in diabetic patients. On the other hand, biofuel cells can be used as an alternative energy source in future implantable devices, such as implantable glucose sensors in the artificial pancreas. Glucose dehydrogenase from Acinetobacter calcoaceticus, which harbors pyrroloquinoline quinone as the prosthetic group (PQQGDH), is one of the enzymes most attractive as a glucose sensor constituent and as the anode enzyme in biofuel cells, due to its high catalytic activity and insensitivity to oxygen. However, the application of PQQGDH for these purposes is inherently limited because an electron mediator is required for the electron transfer to the electrode.

We have recently reported on the development of an engineered enzyme, quinohemoprotein glucose dehydrogenase (QH‐GDH), in which the cytochrome c domain of the quinohemoprotein ethanol dehydrogenase (QH‐EDH) was fused with PQQGDH, to enable electron transfer to the electrode in the absence of an artificial mediator. In this study, we constructed a direct electron‐transfer‐type CGM system employing QH‐GDH. This CGM system showed sufficient current response and high operational stability. Furthermore, we successfully constructed a compartmentless biofuel cell employing QH‐GDH.     

A glucose/hydrogen peroxide biofuel cell that uses oxidase and peroxidase as catalysts by composite bulk-modified bioelectrodes based on a solid binding matrix

An improved composite bulk-modified bioelectrode setup based on a solid binding matrix (SBM) has been used to develop a glucose/hydrogen peroxide biofuel cell. Fuel is combined through a catalytically promoted reaction with oxygen into and oxidized species and electricity. The present work explores the feasibility of a sugar-feed biofuel cell based on SBM technology. The biofuel cell that utilizes mediators as electron transporters from the glucose oxidation pathway of the enzyme directly to electrodes is considered in this work. The anode was a glucose oxidase (GOx, EC 1.1.3.4)/ferrocene-modified SBM/graphite composite electrode. The cathode was a horseradish peroxidase (HRP, EC 1.11.1.7)/ferrocene-modified SBM/graphite composite electrode. The composite transducer material was layered on a wide polymeric surface to obtain the biomodified electrodic elements, anodes and cathodes and were assembled into a biofuel cell using glucose and H(2)O(2) as the fuel substrate and the oxidizer. The electrochemical properties and the characteristics of single composite bioelectrodes are described. The open-circuit voltage of the cell was 0.22 V, and the power output of the cell was 0.15 microW/cm(2) at 0.021 V. The biofuel cell proved to be stable for an extended period of continuous work (30 days). The reproducibility of the biotransducers fabrication was also investigated. In addition, an application of presented biofuel cell, e.g. the use of hydrolyzed corn syrup as renewable biofuels, was discussed.