Co-reporter:Kamrul Hasan, Matteo Grattieri, Tao Wang, Ross D. Milton, and Shelley D. Minteer
ACS Energy Letters September 8, 2017 Volume 2(Issue 9) pp:1947-1947
Publication Date(Web):July 31, 2017
DOI:10.1021/acsenergylett.7b00585
Shewanella oneidensis MR-1 is the model organism used in microbial fuel cells (MFCs). A great deal of research has focused on this bacterium to improve extracellular electron transfer (EET) and subsequently the power output in MFCs. Here, we report on the enhanced bioelectrocatalysis of S. oneidensis MR-1 by using a naphthoquinone redox polymer (NQ-LPEI) on a modified carbon felt electrode. A maximum anodic current of 3.70 ± 0.40 A m–2 is obtained in a three-electrode setup, a value 15 times higher than that obtained for an anode that did not contain the NQ-LPEI redox polymer (0.24 ± 0.05 A m–2). Additionally, a maximum power output of 0.53 ± 0.02 W m–2 was obtained in single-chamber MFCs where the NQ-LPEI modified anode was utilized. The power output was significantly higher than that obtained for MFCs with unmodified anodes (0.19 ± 0.05 W m–2). These findings suggest that NQ-LPEI could be used with known electrogenic microorganisms to further improve the performances of MFCs.
Co-reporter:Lin Xia, Khiem Van Nguyen, Yaovi Holade, Han Han, Kevin Dooley, Plamen Atanassov, Scott Banta, and Shelley D. Minteer
ACS Energy Letters June 9, 2017 Volume 2(Issue 6) pp:1435-1435
Publication Date(Web):May 17, 2017
DOI:10.1021/acsenergylett.7b00134
The development of enzymatic biofuel cells has been plagued by the high cost of enzyme purification and low efficiency of fuel oxidation. Here, we demonstrate a protein purification-free approach to assemble an alcohol dehydrogenase and aldehyde dehydrogenase enzyme cascade-based bioanode for use in a methanol biofuel cell. Each enzyme was fused to a different sequence-specific zinc finger DNA-binding protein. The zinc finger domains serve as both tags to isolate the enzymes from crude cell lysates as well as anchors to immobilize the enzymes on DNA-modified multiwalled carbon nanotubes. The biofuel cells based on the enzyme cascade bioanodes show a maximum power output of 24.5 ± 3.2 μW cm–2, which is comparable to fuel cells utilizing purified enzymes. Further analysis of kinetic behavior revealed a significant increase in the reactivity of the complexes due to substrate channeling of the aldehyde intermediate.
Co-reporter:Yuanchao Liu, David P. Hickey, Jing-Yao Guo, Erica Earl, Sofiene Abdellaoui, Ross D. Milton, Matthew S. Sigman, Shelley D. Minteer, and Scott Calabrese Barton
ACS Catalysis April 7, 2017 Volume 7(Issue 4) pp:2486-2486
Publication Date(Web):February 27, 2017
DOI:10.1021/acscatal.6b03440
Natural enzyme cascades utilize electrostatic guidance as an effective technique to control the diffusion of charged reaction intermediates between catalytic active sites in a process known as substrate channeling. However, the limited understanding of channeling mechanisms has abated the application of this technique in artificial catalytic cascades. In this work, we utilize molecular dynamics simulations to describe the transport of anionic intermediates (e.g., oxalate and glucose-6-phosphate) on a theoretical cationic α-helix peptide bridge and identify rules for molecular-level design of electrostatic channeling. These simulations allowed us to elucidate a surface diffusion mechanism whereby the anionic intermediate undergoes discrete hydrogen-bonding interactions along adjacent cationic residues on the peptide bridge. Using MD simulations as a foundational blueprint, we synthesized an enzyme complex using a poly(lysine) peptide chain as a cationic bridge between glucose-6-phosphate dehydrogenase and hexokinase. Stopped-flow lag time experiments demonstrate the ability of the artificially linked enzyme complex to facilitate electrostatic substrate channeling, while an analogous neutral poly(glycine)-bridged complex was used as a control to isolate proximity effects from artificial substrate channeling.Keywords: electrostatic diffusion; enzyme cascade; glucose-6-phosphate dehydrogenase; hexokinase; poly(lysine); surface diffusion;
Co-reporter:Florika C. Macazo;David P. Hickey;Sofiene Abdellaoui;Matthew S. Sigman
Chemical Communications 2017 vol. 53(Issue 74) pp:10310-10313
Publication Date(Web):2017/09/14
DOI:10.1039/C7CC05724E
The development of a hybrid, tri-catalytic architecture is demonstrated by immobilizing MWCNTs, TEMPO-modified linear poly(ethylenimine) and oxalate decarboxylase on an electrode to enable enhanced electrochemical oxidation of glycerol. This immobilized, hybrid catalytic motif results in a synergistic 3.3-fold enhancement of glycerol oxidation and collects up to 14 electrons per molecule of glycerol.
Co-reporter:Timothy Quah;Ross D. Milton;Sofiene Abdellaoui
Chemical Communications 2017 vol. 53(Issue 60) pp:8411-8414
Publication Date(Web):2017/07/25
DOI:10.1039/C7CC03842A
Diaphorase and a benzylpropylviologen redox polymer were combined to create a bioelectrode that can both oxidize NADH and reduce NAD+. We demonstrate how bioelectrocatalytic NAD+/NADH inter-conversion can transform a glucose/O2 enzymatic fuel cell (EFC) with an open circuit potential (OCP) of 1.1 V into an enzymatic redox flow battery (ERFB), which can be rapidly recharged by operation as an EFC.
Co-reporter:Sofiene Abdellaoui;Madelaine Seow Chavez;Ivana Matanovic;Andrew R. Stephens;Plamen Atanassov
Chemical Communications 2017 vol. 53(Issue 39) pp:5368-5371
Publication Date(Web):2017/05/11
DOI:10.1039/C7CC01027C
Glycerol is a common fuel considered for bioenergy applications. Computational docking studies were performed on formate dehydrogenase from Candida boidinii (cbFDH) that showed that mesoxalate can bind to the buried active site of the holo form predicting that mesoxalate, a byproduct of glycerol oxidation, may act as its substrate. Spectroscopic assays and characterization by HPLC and GC/TCD have shown for the first time that cbFDH can act as a decarboxylase with mesoxalate. From this assessment, cbFDH was combined with NH2-TEMPO to form a novel hybrid anode to oxidize glycerol to carbon dioxide at near-neutral pH.
Co-reporter:M. Grattieri;K. Hasan;R. D. Milton;S. Abdellaoui;M. Suvira;B. Alkotaini;S. D. Minteer
Sustainable Energy & Fuels (2017-Present) 2017 vol. 1(Issue 7) pp:1568-1572
Publication Date(Web):2017/08/22
DOI:10.1039/C7SE00270J
The optimization of bioelectrochemical systems operating with microorganisms requires a deep understanding of the extracellular electron transfer (EET) processes, however, EET studies have been reported for few bacterial species. Herein, the bioelectrocatalytic properties of Rikenella microfusus, an anaerobic bacterium commonly found in electrode-colonizing biofilms, have been investigated for the first time.
Co-reporter:Ricardo A. Escalona-Villalpando, Russell C. Reid, Ross D. Milton, L.G. Arriaga, Shelley D. Minteer, Janet Ledesma-García
Journal of Power Sources 2017 Volume 342(Volume 342) pp:
Publication Date(Web):28 February 2017
DOI:10.1016/j.jpowsour.2016.12.082
•First evaluation of a microfluidic lactate enzymatic fuel cell.•Demonstrate that microfluidic biofuel cells can improve performance 6.6 fold.•Highest current density, single step oxidation lactate biofuel cell.Lactate/O2 biofuel cells (BFC) can have high theoretical energy densities due to high solubility and high fuel energy density; however, they are rarely studied in comparison to glucose BFCs. In this paper, lactate oxidase (LOx) was coupled with a ferrocene-based redox polymer (dimethylferrocene-modified linear polyethylenimine, FcMe2-LPEI) as the bioanode and laccase (Lc) connected to pyrene-anthracene modified carbon nanotubes (PyrAn-MWCNT) to facilitate the direct electron transfer (DET) at the biocathode. Both electrodes were evaluated in two BFC configurations using different concentrations of lactate, in the range found in sweat (0–40 mM). A single compartment BFC evaluated at pH 5.6 provided an open circuit potential (OCP) of 0.68 V with a power density of 61.2 μWcm−2. On the other hand, a microfluidic BFC operating under the same conditions resulted in an OCP of 0.67 V, although an increase in the power density, increasing to 305 μW cm−2, was observed. Upon changing the pH to 7.4 in only the anolyte, its performance was further increased to 0.73 V and 404 μW cm−2, respectively. This work reports the first microfluidic lactate/oxygen enzymatic BFC and shows the importance of microfluidic flow in high performing BFCs where lactate is utilized as the fuel and O2 is the final electron acceptor.
Co-reporter:Matteo Grattieri, Milomir Suvira, Kamrul Hasan, Shelley D. Minteer
Journal of Power Sources 2017 Volume 356(Volume 356) pp:
Publication Date(Web):15 July 2017
DOI:10.1016/j.jpowsour.2016.11.090
•Halotolerant extremophile bacteria as bioelectrocatalysts in microbial fuel cells.•Possible treatment of hypersaline wastewater in Pt-free microbial fuel cells.•Magnesium salts recovery at the cathode electrode.The treatment of hypersaline wastewater (approximately 5% of the wastewater worldwide) cannot be performed by classical biological techniques. Herein the halotolerant extremophile bacteria obtained from the Great Salt Lake (Utah) were explored in single chamber microbial fuel cells with Pt-free cathodes for more than 18 days. The bacteria samples collected in two different locations of the lake (Stansbury Bay and Antelope Island) showed different electrochemical performances. The maximum achieved power output of 36 mW m−2 was from the microbial fuel cell based on the sample originated from Stansbury Bay, at a current density of 820 mA m−2. The performances throughout the long-term operation are discussed and a bioelectrochemical mechanism is proposed.Download high-res image (154KB)Download full-size image
Co-reporter:Florika C. Macazo, Shelley D. Minteer
Current Opinion in Electrochemistry 2017 Volume 5, Issue 1(Volume 5, Issue 1) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.coelec.2017.07.010
•Natural, non-natural, and hybrid enzyme cascades utilized in biofuel cells are discussed.•Enzymatic bioanodes utilize linear, cyclic, parallel, and random sequential cascades.•Future research will require advancements in scaffolding for substrate channeling.Enzymatic biofuel cells are a class of fuel cells that utilize oxidoreductase proteins to catalyze the oxidation of fuel and/or the reduction of oxygen. Although biofuel cell cathodes typically utilize a single enzyme system, enzyme cascades are frequently necessary in biofuel cell anodes to enable deep or complete oxidation of fuels, since most oxidase and dehydrogenase enzymes only catalyze two-electron oxidation of substrates. Herein, we detail a summary of all the significant advancements made using enzyme cascades in recent years. We present examples of natural, non-natural and hybrid enzyme cascades that have been used in biofuel cells and hybrid fuel cells, and classified them either as linear, cyclic, random sequential or parallel cascades. We conclude by discussing the future directions that are necessary to the field.
Co-reporter:Dr. Ross D. Milton;Rong Cai;Dr. Sofiene Abdellaoui; Dónal Leech;Dr. Antonio L. De Lacey;Dr. Marcos Pita; Shelley D. Minteer
Angewandte Chemie 2017 Volume 129(Issue 10) pp:2724-2727
Publication Date(Web):2017/03/01
DOI:10.1002/ange.201612500
AbstractNitrogenases are the only enzymes known to reduce molecular nitrogen (N2) to ammonia (NH3). By using methyl viologen (N,N′-dimethyl-4,4′-bipyridinium) to shuttle electrons to nitrogenase, N2 reduction to NH3 can be mediated at an electrode surface. The coupling of this nitrogenase cathode with a bioanode that utilizes the enzyme hydrogenase to oxidize molecular hydrogen (H2) results in an enzymatic fuel cell (EFC) that is able to produce NH3 from H2 and N2 while simultaneously producing an electrical current. To demonstrate this, a charge of 60 mC was passed across H2 /N2 EFCs, which resulted in the formation of 286 nmol NH3 mg−1 MoFe protein, corresponding to a Faradaic efficiency of 26.4 %.
Co-reporter:Ross D. Milton, Sofiene Abdellaoui, Nimesh Khadka, Dennis R. Dean, Dónal Leech, Lance C. Seefeldt and Shelley D. Minteer
Energy & Environmental Science 2016 vol. 9(Issue 8) pp:2550-2554
Publication Date(Web):20 Jun 2016
DOI:10.1039/C6EE01432A
Nitrogenase is the only enzyme known to catalyze the reduction of N2 to 2NH3. In vivo, the MoFe protein component of nitrogenase is exclusively reduced by the ATP-hydrolyzing Fe protein in a series of transient association/dissociation steps that are linked to the hydrolysis of two ATP for each electron transferred. We report MoFe protein immobilized at an electrode surface, where cobaltocene (as an electron mediator that can be observed in real time at a carbon electrode) is used to reduce the MoFe protein (independent of the Fe protein and of ATP hydrolysis) and support the bioelectrocatalytic reduction of protons to dihydrogen, azide to ammonia, and nitrite to ammonia. Bulk bioelectrosynthetic N3− or NO2− reduction (50 mM) for 30 minutes yielded 70 ± 9 nmol NH3 and 234 ± 62 nmol NH3, with NO2− reduction operating at high faradaic efficiency.
Co-reporter:Lindsey N. Pelster and Shelley D. Minteer
ACS Catalysis 2016 Volume 6(Issue 8) pp:4995
Publication Date(Web):June 22, 2016
DOI:10.1021/acscatal.6b00950
Researchers have proposed that the efficiency of the electron transport chain is due to the synergy among complexes I, III, and IV in the membrane. In this paper, the enzymes of the supercomplex were isolated together, reconstituted into lipids that mimic the inner membrane of mitochondria, and immobilized in a tethered lipid bilayer on a gold electrode. The supercomplex enzymes retained their activity with the addition of their substrates and were inhibited by their respective toxins. The bioelectrocatalytic studies indicate the interdependence of the activity of the different complexes in the bioelectrocatalysis of the electron transport chain supercomplex. These fundamental studies provide a starting point to consider the use of supercomplexes and enzyme cascades for bioenergy conversion applications and biosensing through the regulation of the activity by inhibition.Keywords: bioelectrocatalysis; cytochrome c; electron transport chain; enzyme cascade; metabolon; tethered lipid bilayer
Co-reporter:Khiem Van Nguyen, Yaovi Holade, and Shelley D. Minteer
ACS Catalysis 2016 Volume 6(Issue 4) pp:2603
Publication Date(Web):March 10, 2016
DOI:10.1021/acscatal.5b02699
We present the preparation of a redox DNA hydrogel for mediated bioelectrocatalysis of oxidoreductase enzymes for biosensor and biofuel cell applications. The noncovalent functionalization of DNA with redox molecules is achieved by intercalation of aromatic redox probes into the DNA double helix or electrostatic binding of redox-active tetraalkylammonium ions to phosphate groups on DNA. Prepared DNA redox hydrogels demonstrate the capability of mediating bioelectrocatalytic glucose oxidation by oxidoreductase enzymes. This is the first evidence that redox DNA hydrogels can replace redox polymer hydrogels for self-exchange-based mediation for bioelectrocatalytic applications. This study contributes toward advances in the use of DNA, an emerging biomaterial, in enzymatic bioelectrocatalysis-based applications.
Co-reporter:Sofiene Abdellaoui, Ross D. Milton, Timothy Quah and Shelley D. Minteer
Chemical Communications 2016 vol. 52(Issue 6) pp:1147-1150
Publication Date(Web):24 Nov 2015
DOI:10.1039/C5CC09161F
Electron mediation between NAD-dependent enzymes using quinone moieties typically requires the use of a diaphorase as an intermediary enzyme. The ability for a naphthoquinone redox polymer to independently oxidize enzymatically-generated NADH is demonstrated for application to glucose/O2 enzymatic fuel cells.
Co-reporter:Tao Wang, Ross D. Milton, Sofiene Abdellaoui, David P. Hickey, and Shelley D. Minteer
Analytical Chemistry 2016 Volume 88(Issue 6) pp:3243
Publication Date(Web):February 11, 2016
DOI:10.1021/acs.analchem.5b04651
The reversible inhibition of laccase by arsenite (As3+) and arsenate (As5+) is reported for the first time. Oxygen-reducing laccase bioelectrodes were found to be inhibited by both arsenic species for direct electron-transfer bioelectrodes (using anthracene functionalities for enzymatic orientation) and for mediated electron-transfer bioelectrodes [using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as an electron mediator]. Both arsenic species were determined to behave via a mixed inhibition model (behaving closely to that of uncompetitive inhibitors) when evaluated spectrophotometrically using ABTS as the electron donor. Finally, laccase bioelectrodes were employed within an enzymatic fuel cell, yielding a self-powered biosensor for arsenite and arsenate. This conceptual self-powered arsenic biosensor demonstrated limits of detection (LODs) of 13 μM for arsenite and 132 μM for arsenate. Further, this device possessed sensitivities of 0.91 ± 0.07 mV/mM for arsenite and 0.98 ± 0.02 mV/mM for arsenate.
Co-reporter:Maria José González-Guerrero, F. Javier del Campo, Juan Pablo Esquivel, Fabien Giroud, Shelley D. Minteer, Neus Sabaté
Journal of Power Sources 2016 Volume 326() pp:410-416
Publication Date(Web):15 September 2016
DOI:10.1016/j.jpowsour.2016.07.014
•A Biofuel Cell in which fluid transport is based on capillary action is presented.•The paper-based fuel cell is able to produce the same power output as one operated with an external syringe pump.•The system is simplified by evolving a two-stream flow device to a single-stream format.•The single stream fuel cell has the potential of powering a real application.This work presents a first approach towards the development of a cost-effective enzymatic paper-based glucose/O2 microfluidic fuel cell in which fluid transport is based on capillary action. A first fuel cell configuration consists of a Y-shaped paper device with the fuel and the oxidant flowing in parallel over carbon paper electrodes modified with bioelectrocatalytic enzymes. The anode consists of a ferrocenium-based polyethyleneimine polymer linked to glucose oxidase (GOx/Fc-C6-LPEI), while the cathode contains a mixture of laccase, anthracene-modified multiwall carbon nanotubes, and tetrabutylammonium bromide-modified Nafion (MWCNTs/laccase/TBAB-Nafion). Subsequently, the Y-shaped configuration is improved to use a single solution containing both, the anolyte and the catholyte. Thus, the electrolytes pHs of the fuel and the oxidant solutions are adapted to an intermediate pH of 5.5. Finally, the fuel cell is run with this single solution obtaining a maximum open circuit of 0.55 ± 0.04 V and a maximum current and power density of 225 ± 17 μA cm−2 and 24 ± 5 μW cm−2, respectively. Hence, a power source closer to a commercial application (similar to conventional lateral flow test strips) is developed and successfully operated. This system can be used to supply the energy required to power microelectronics demanding low power consumption.
Co-reporter:Sidney Aquino Neto, Ross D. Milton, David P. Hickey, Adalgisa R. De Andrade, Shelley D. Minteer
Journal of Power Sources 2016 Volume 324() pp:208-214
Publication Date(Web):30 August 2016
DOI:10.1016/j.jpowsour.2016.05.073
•Ethanol bioelectrooxidation was achieved in a membraneless enzymatic biofuel cell.•PQQ-dependent ADH and NAD+-dependent ADH showed ethanol bioelectrocatalysis.•Bilirubin oxidase-based biocathodes provided efficient oxygen reduction.•PQQ-dependent ADH bioanode in MET mode displayed the best biofuel cell performance.The bioelectrooxidation of ethanol was investigated in a fully enzymatic membraneless ethanol/O2 biofuel cell assembly using hybrid bioanodes containing multi-walled carbon nanotube (MWCNT)-decorated gold metallic nanoparticles with either a pyrroloquinoline quinone (PQQ)-dependent alcohol dehydrogenase (ADH) enzyme or a nicotinamide adenine dinucleotide (NAD+)-dependent ADH enzyme. The biofuel cell anode was prepared with the PQQ-dependent enzyme and designed using either a direct electron transfer (DET) architecture or via a mediated electron transfer (MET) configuration through a redox polymer, 1,1′-dimethylferrocene-modified linear polyethyleneimine (FcMe2-C3-LPEI). In the case of the bioanode containing the NAD+-dependent enzyme, only the mediated electron transfer mechanism was employed using an electropolymerized methylene green film to regenerate the NAD+ cofactor. Regardless of the enzyme being employed at the anode, a bilirubin oxidase-based biocathode prepared within a DET architecture afforded efficient electrocatalytic oxygen reduction in an ethanol/O2 biofuel cell. The power curves showed that DET-based bioanodes via the PQQ-dependent ADH still lack high current densities, whereas the MET architecture furnished maximum power density values as high as 226 ± 21 μW cm−2. Considering the complete membraneless enzymatic biofuel cell with the NAD+-dependent ADH-based bioanode, power densities as high as 111 ± 14 μW cm−2 were obtained. This shows the advantage of PQQ-dependent ADH for membraneless ethanol/O2 biofuel cell applications.
Co-reporter:Michelle Rasmussen, Sofiene Abdellaoui, Shelley D. Minteer
Biosensors and Bioelectronics 2016 Volume 76() pp:91-102
Publication Date(Web):15 February 2016
DOI:10.1016/j.bios.2015.06.029
•Review of advancements in the field of enzymatic biofuel cells over the last 30 years.•Detailed discussion of the applications of enzymatic biofuel cells in biosensing and bioelectronics.•Detailed challenges for the future research and development in enzymatic biofuel cells.Enzymatic biofuel cells are bioelectronic devices that utilize oxidoreductase enzymes to catalyze the conversion of chemical energy into electrical energy. This review details the advancements in the field of enzymatic biofuel cells over the last 30 years. These advancements include strategies for improving operational stability and electrochemical performance, as well as device fabrication for a variety of applications, including implantable biofuel cells and self-powered sensors. It also discusses the current scientific and engineering challenges in the field that will need to be addressed in the future for commercial viability of the technology.
Co-reporter:David P. Hickey, Russell C. Reid, Ross D. Milton, Shelley D. Minteer
Biosensors and Bioelectronics 2016 Volume 77() pp:26-31
Publication Date(Web):15 March 2016
DOI:10.1016/j.bios.2015.09.013
•A self-powered lactate sensor a redox polymer with lactate oxidase as an anode.•Maximum current and sensitivity were 1.51±0.13 mA cm−2 and 400±20 μA cm−2 mM−1.•The self-powered sensor generated 122 μW cm−2 with a sensitivity of 45±6 μA cm−2 mM−1.•The lactate sensor maintained activity even after 21 days of storage at 4 °C.Lactate is an important biomarker due to its excessive production by the body during anerobic metabolism. Existing methods for electrochemical lactate detection require the use of an external power source to supply a positive potential to the working electrode of a given device. Herein we describe a self-powered amperometric lactate biosensor that utilizes a dimethylferrocene-modified linear poly(ethylenimine) (FcMe2-LPEI) hydrogel to simultaneously immobilize and mediate electron transfer from lactate oxidase (LOx) at the anode and a previously described enzymatic cathode. Operating as a half-cell, the FcMe2-LPEI electrode material generates a jmax of 1.51±0.13 mA cm−2 with a KM of 1.6±0.1 mM and a sensitivity of 400±20 μA cm−2 mM−1 while operating with an applied potential of 0.3 V vs. SCE. When coupled with an enzymatic biocathode, the self-powered biosensor has a detection range between 0 mM and 5 mM lactate with a sensitivity of 45±6 μA cm−2 mM−1. Additionally, the FcMe2-LPEI/LOx-based self-powered sensor is capable of generating a power density of 122±5 μW cm−2 with a current density of 657±17 μA cm−2 and an open circuit potential of 0.57±0.01 V, which is sufficient to act as a supplemental power source for additional small electronic devices.
Co-reporter:Ross D. Milton, Tao Wang, Krysti L. Knoche, and Shelley D. Minteer
Langmuir 2016 Volume 32(Issue 10) pp:2291-2301
Publication Date(Web):February 21, 2016
DOI:10.1021/acs.langmuir.5b04742
Bioelectrocatalysis is an expanding research area due to the use of this type of electrocatalysis in electrochemical biosensors, biofuel cells, bioelectrochemical cells, and biosolar cells. This feature article discusses recent advancements in tailoring the biointerface between electrodes and biocatalysts for facile electrocatalysis. This includes the design of pyrene moieties for directing the orientation of biocatalysts on electrode surfaces and mediation as well as the rational design of redox polymers for self-exchange-based electron transport to/from biocatalysts and the electrode and the use of bioscaffolding techniques for designing the bioelectrode structure. However, recent advances in the past decade have shown the importance of hybrid bioelectrocatalytic systems, and future work will be needed to use these same pyrene, redox polymer, and bioscaffolding techniques for hybrid bioelectrocatalysis.
Co-reporter:Krysti L. Knoche, David P. Hickey, Ross D. Milton, Carol L. Curchoe, and Shelley D. Minteer
ACS Energy Letters 2016 Volume 1(Issue 2) pp:380
Publication Date(Web):July 19, 2016
DOI:10.1021/acsenergylett.6b00225
Small implantable electronic devices require biologically compatible energy sources that are capable of delivering quick high-energy pulses. Combining batteries and supercapacitors allows for high power and energy density while providing both small size and biocompatibility. Here, we report a hybrid supercapacitor/biobattery whereby an oxygen-reducing cathode of bilirubin oxidase immobilized with anthracene-modified carbon nanotubes and tetrabutylammonium bromide-modified Nafion is coupled with a glucose bioanode of flavin adenine dinucleotide-dependent glucose dehydrogenase. The redox polymer, dimethylferrocene-modified linear poly(ethylenimine), used at the bioanode simultaneously immobilizes enzyme, mediates electron transfer, and acts as a pseudocapacitor where capacitance of the anode scales with increased polymer loading. Both multiwalled carbon nanotubes and carbon felt incorporated into the anode construction improve polymer conductivity, subsequently resulting in further improved anodic capacitance. A supercapacitor/biobattery device of the above configuration results in a specific capacitance of 300 ± 100 F/g, which is over 4 times higher than that of other reported biologically derived supercapacitors.
Co-reporter:David P. Hickey; David A. Schiedler; Ivana Matanovic; Phuong Vy Doan; Plamen Atanassov; Shelley D. Minteer;Matthew S. Sigman
Journal of the American Chemical Society 2015 Volume 137(Issue 51) pp:16179-16186
Publication Date(Web):December 3, 2015
DOI:10.1021/jacs.5b11252
Stable nitroxyl radical-containing compounds, such as 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) and its derivatives, are capable of electrocatalytically oxidizing a wide range of alcohols under mild and environmentally friendly conditions. Herein, we examine the structure–function relationships that determine the catalytic activity of a diverse range of water-soluble nitroxyl radical compounds. A strong correlation is described between the difference in the electrochemical oxidation potentials of a compound and its electrocatalytic activity. Additionally, we construct a simple computational model that is able to accurately predict the electrochemical potential and catalytic activity of a wide range of nitroxyl radical derivatives.
Co-reporter:Ross D. Milton, David P. Hickey, Sofiene Abdellaoui, Koun Lim, Fei Wu, Boxuan Tan and Shelley D. Minteer
Chemical Science 2015 vol. 6(Issue 8) pp:4867-4875
Publication Date(Web):08 Jun 2015
DOI:10.1039/C5SC01538C
Enzymatic fuel cells (EFCs) are devices that can produce electrical energy by enzymatic oxidation of energy-dense fuels (such as glucose). When considering bioanode construction for EFCs, it is desirable to use a system with a low onset potential and high catalytic current density. While these two properties are typically mutually exclusive, merging these two properties will significantly enhance EFC performance. We present the rational design and preparation of an alternative naphthoquinone-based redox polymer hydrogel that is able to facilitate enzymatic glucose oxidation at low oxidation potentials while simultaneously producing high catalytic current densities. When coupled with an enzymatic biocathode, the resulting glucose/O2 EFC possessed an open-circuit potential of 0.864 ± 0.006 V, with an associated maximum current density of 5.4 ± 0.5 mA cm−2. Moreover, the EFC delivered its maximum power density (2.3 ± 0.2 mW cm−2) at a high operational potential of 0.55 V.
Co-reporter:Ross D. Milton, Fei Wu, Koun Lim, Sofiene Abdellaoui, David P. Hickey, and Shelley D. Minteer
ACS Catalysis 2015 Volume 5(Issue 12) pp:7218
Publication Date(Web):November 9, 2015
DOI:10.1021/acscatal.5b01777
Enzymatic biofuel cells (EFCs) are devices that are capable of producing electrical energy from the enzymatic oxidation of simple, energy-dense fuels (such as sugars and alcohols). Glucose oxidase (GOx) is perhaps the most widely used enzyme at the bioanode of EFCs, affording devices that can be fueled by glucose. Due to its high substrate specificity, GOx was initially employed in glucose biosensor applications, which later translated into EFC technology. This high substrate specificity, however, often restricts EFC devices to operation on single fuels. Herein, we report the use of a commercial GOx with greater substrate promiscuity (broader substrate GOx, “bGOx”), which can result in the fabrication of EFCs that can utilize a single versatile catalyst for the oxidation of many mono-, di-, tri-, and polysaccharides. The EFCs presented within this study were fueled by glucose, maltose, maltotriose, cellobiose, lactose, galactose, and xylose. Additionally, the ability for the same biocatalyst to oxidize sugars from alternative sources was investigated, with EFCs producing electrical energy from lactose within dairy milk (0.43 ± 0.01 mA cm–2 and 80.1 ± 1.2 μW cm–2) and starch solutions (0.19 ± 0.00 mA cm–2 and 50.9 ± 0.9 μW cm–2).Keywords: enzymatic fuel cell; enzyme engineering; glucose oxidase; lactose oxidation; milk fuel cell; saccharides
Co-reporter:David P. Hickey, Ross D. Milton, Dayi Chen, Matthew S. Sigman, and Shelley D. Minteer
ACS Catalysis 2015 Volume 5(Issue 9) pp:5519
Publication Date(Web):August 14, 2015
DOI:10.1021/acscatal.5b01668
We demonstrate a method to simultaneously immobilize the oxidation catalyst, TEMPO, while dramatically enhancing its electrocatalytic activity toward several biologically available alcohols. TEMPO is covalently immobilized onto linear poly(ethylenimine), which is then cross-linked onto the surface of a glassy carbon electrode to form a hydrogel through which substrates can readily diffuse. The TEMPO-LPEI electrode is used as an anode capable of generating currents from 0.41 ± 0.06 mA cm–2 in the presence of 250 mM sucrose to 8.20 ± 0.04 mA cm–2 in the presence of 2 M methanol and 33.4 ± 9.4 mA cm–2 in the presence of 500 mM formate under neutral pH and at 25 °C. The newly described anode is combined with an enzymatic biocathode to construct a hybrid biofuel cell to produce 0.38 ± 0.04 mA cm–2 while using 2 M methanol as a fuel source.Keywords: alcohols; electrocatalysis; hybrid fuel cell; oxidation; TEMPO
Co-reporter:Fabien Giroud, Ross D. Milton, Bo-Xuan Tan, and Shelley D. Minteer
ACS Catalysis 2015 Volume 5(Issue 2) pp:1240
Publication Date(Web):January 13, 2015
DOI:10.1021/cs501940g
An elegant method to perform bioelectocatalysis with different oxidoreductases at the cathode and at the anode of an enzymatic biofuel cell is presented. Noncovalent functionalization of multiwalled carbon nanotubes (MWCNTs) was accomplished via π–π interactions of pyrene derivatives. 1-[Bis(2-naphthoquinonyl)aminomethyl]pyrene was synthesized and successfully immobilized on MWCNTs. The incorporation of the quinone-modified MWCNTs within enzymatic bioelectrocatalytic applications was evaluated. The hydrophobic nature of the naphthoquinone aided orientation of laccase and bilirubin oxidase toward the electrode, which enhanced their ability to undergo the direct bioelectrocatalysis of oxygen. In contrast, the electrochemical properties of the quinone were used at the bioanode to mediate electrons from the bioelectrocatalytic oxidation of glucose by pyrroloquinoline quinone-dependent glucose dehydrogenase. This method demonstrates how the smart modification of MWCNTs can develop materials, which can be used simultaneously at both electrodes of enzymatic biofuel cells.Keywords: bioelectrocatalysis; biofuel cells; glucose oxidase; multicopper oxidases; pyrene; quinones
Co-reporter:Fei Wu, Lindsey N. Pelster and Shelley D. Minteer
Chemical Communications 2015 vol. 51(Issue 7) pp:1244-1247
Publication Date(Web):28 Nov 2014
DOI:10.1039/C4CC08702J
Dynamics of metabolon formation in mitochondria was probed by studying diffusional motion of two sequential Krebs cycle enzymes in a microfluidic channel. Enhanced directional co-diffusion of both enzymes against a substrate concentration gradient was observed in the presence of intermediate generation. This reveals a metabolite directed compartmentation of metabolic pathways.
Co-reporter:Khiem Van Nguyen and Shelley D. Minteer
Chemical Communications 2015 vol. 51(Issue 66) pp:13071-13073
Publication Date(Web):06 Jul 2015
DOI:10.1039/C5CC04810A
We report the usage of DNA hydrogels for enzyme entrapment in an enzymatic biobattery. With the recent advancements in DNA nanotechnology, the incorporation of DNA materials to bioelectrocatalytic electrodes holds great promise to improve the performance of bioelectrocatalysis-based devices.
Co-reporter:Sofiene Abdellaoui, David P. Hickey, Andrew R. Stephens and Shelley D. Minteer
Chemical Communications 2015 vol. 51(Issue 76) pp:14330-14333
Publication Date(Web):10 Aug 2015
DOI:10.1039/C5CC06131H
The complete electro-oxidation of glycerol to CO2 is performed through an oxidation cascade using a hybrid catalytic system combining a recombinant enzyme, oxalate decarboxylase from Bacillus subtilis, and an organic oxidation catalyst, 4-amino-TEMPO. This system is capable of electrochemically oxidizing glycerol at a carbon electrode collecting all 14 electrons per molecule.
Co-reporter:Khiem Van Nguyen and Shelley D. Minteer
Chemical Communications 2015 vol. 51(Issue 23) pp:4782-4784
Publication Date(Web):11 Feb 2015
DOI:10.1039/C4CC10250A
We present here the construction of a DNA biosensor based on a tubular micromotor that only produces motion-based signal in the presence of DNA target. This “turn on” characteristic of the sensor is achieved by the addition of Pt nanoparticle-DNA conjugate as the motion-inducing catalyst for the micromotors through DNA hybridization. Our work potentially offers new design strategies for motion-based biosensors with higher specificity.
Co-reporter:Sidney Aquino Neto, Ross D. Milton, Laís B. Crepaldi, David P. Hickey, Adalgisa R. de Andrade, Shelley D. Minteer
Journal of Power Sources 2015 Volume 285() pp:493-498
Publication Date(Web):1 July 2015
DOI:10.1016/j.jpowsour.2015.03.121
•Au nanoparticles electrooxidize glucose even under acidic conditions.•A hybrid configuration improve electrochemical response towards glucose oxidation.•Higher catalytic current is obtained with the hybrid bioelectrode.•The prepared hybrid bioanode provided more than 30% increase in power.Recently, there has been much effort in developing metal nanoparticle catalysts for fuel oxidation, as well as the development of enzymatic bioelectrocatalysts for fuel oxidation. However, there has been little study of the synergy of hybrid electrocatalytic systems. We report the preparation of hybrid bioanodes based on Au nanoparticles supported on multi-walled carbon nanotubes (MWCNTs) co-immobilized with glucose oxidase (GOx). Mediated electron transfer was achieved by two strategies: ferrocene entrapped within polypyrrole and a ferrocene-modified linear poly(ethylenimine) (Fc-LPEI) redox polymer. Electrochemical characterization of the Au nanoparticles supported on MWCNTs indicate that this catalyst exhibits an electrocatalytic response for glucose even in acidic conditions. Using the redox polymer Fc-LPEI as the mediator, voltammetric and amperometric data demonstrated that these bioanodes can efficiently achieve mediated electron transfer and also indicated higher catalytic currents with the hybrid bioelectrode. From the amperometry, the maximum current density (Jmax) achieved with the hybrid bioelectrode was 615 ± 39 μA cm−2, whereas the bioanode employing GOx only achieved a Jmax of 409 ± 26 μA cm−2. Biofuel cell tests are consistent with the electrochemical characterization, thus confirming that the addition of the metallic species into the bioanode structure can improve fuel oxidation and consequently, improve the power generated by the system.
Co-reporter:Dayi Chen, Shelley D. Minteer
Journal of Power Sources 2015 Volume 284() pp:27-37
Publication Date(Web):15 June 2015
DOI:10.1016/j.jpowsour.2015.02.143
•NiOOH catalyzes methanol oxidation in alkaline media.•A high methanol to OH− ratio could poison the NiOOH sites during methanol oxidation.•Oxygen evolution is preferred over methanol oxidation at high pH.•NiOOH is more efficient as an oxygen evolution catalyst than a methanol oxidation catalyst.Nickel based catalysts have been studied as catalysts for either organic compound (especially methanol) oxidation or oxygen evolution reactions in alkaline medium for decades, but methanol oxidation and oxygen evolution reactions occur at a similar potential range and pH with nickel based catalysts. In contrast to previous studies, we studied these two reactions simultaneously under various pH and methanol concentrations with electrodes containing a series of NiOOH surface concentrations. We found that nickel based catalysts are more suitable to be used as oxygen evolution catalysts than methanol oxidation catalysts based on the observation that: The rate-determining step of methanol oxidation involves NiOOH, OH− and methanol while high methanol to OH− ratio could poison the NiOOH sites. Since NiOOH is involved in the rate-determining step, methanol oxidation suffers from high overpotential and oxygen evolution is favored over methanol oxidation in the presence of an equivalent amount (0.1 M) of alkali and methanol.
Co-reporter:Fei Wu ; Shelley Minteer
Angewandte Chemie 2015 Volume 127( Issue 6) pp:1871-1874
Publication Date(Web):
DOI:10.1002/ange.201409336
Abstract
It has been hypothesized that the high metabolic flux in the mitochondria is due to the self-assembly of enzyme supercomplexes (called metabolons) that channel substrates from one enzyme to another, but there has been no experimental confirmation of this structure or the channeling. A structural investigation of enzyme organization within the Krebs cycle metabolon was accomplished by in vivo cross-linking and mass spectrometry. Eight Krebs cycle enzyme components were isolated upon chemical fixation, and interfacial residues between mitochondrial malate dehydrogenase, citrate synthase, and aconitase were identified. Using constraint protein docking, a low-resolution structure for the three-enzyme complex was achieved, as well as the two-fold symmetric octamer. Surface analysis showed formation of electrostatic channeling upon protein–protein association, which is the first structural evidence of substrate channeling in the Krebs cycle metabolon.
Co-reporter:Sidney Aquino Neto, David P. Hickey, Ross D. Milton, Adalgisa R. De Andrade, Shelley D. Minteer
Biosensors and Bioelectronics 2015 Volume 72() pp:247-254
Publication Date(Web):15 October 2015
DOI:10.1016/j.bios.2015.05.011
•Direct and mediated electron transfer using PQQ-ADH and AldDH were investigated.•TBAB-modified Nafion bioanode provided the best electrochemical response.•Bioanodes containing MWCNTs or Au nanoparticles showed enhanced performance.•High currents were obtained with ferrocene-modified LPEI redox polymer bioanodes.In this paper, we explore the bioelectrooxidation of ethanol using pyrroloquinoline quinone (PQQ)-dependent alcohol and aldehyde dehydrogenase (ADH and AldDH) enzymes for biofuel cell applications. The bioanode architectures were designed with both direct electron transfer (DET) and mediated electron transfer (MET) mechanisms employing high surface area materials such as multi-walled carbon nanotubes (MWCNTs) and MWCNT-decorated gold nanoparticles, along with different immobilization techniques. Three different polymeric matrices were tested (tetrabutyl ammonium bromide (TBAB)-modified Nafion; octyl-modified linear polyethyleneimine (C8-LPEI); and cellulose) in the DET studies. The modified Nafion membrane provided the best electrical communication between enzymes and the electrode surface, with catalytic currents as high as 16.8±2.1 µA cm−2. Then, a series of ferrocene redox polymers were evaluated for MET. The redox polymer 1,1′-dimethylferrocene-modified linear polyethyleneimine (FcMe2-C3-LPEI) provided the best electrochemical response. Using this polymer, the electrochemical assays conducted in the presence of MWCNTs and MWCNTs–Au indicated a Jmax of 781±59 µA cm−2 and 925±68 µA cm−2, respectively. Overall, from the results obtained here, DET using the PQQ-dependent ADH and AldDH still lacks high current density, while the bioanodes that operate via MET employing ferrocene-modified LPEI redox polymers show efficient energy conversion capability in ethanol/air biofuel cells.
Co-reporter:Fei Wu ; Shelley Minteer
Angewandte Chemie International Edition 2015 Volume 54( Issue 6) pp:1851-1854
Publication Date(Web):
DOI:10.1002/anie.201409336
Abstract
It has been hypothesized that the high metabolic flux in the mitochondria is due to the self-assembly of enzyme supercomplexes (called metabolons) that channel substrates from one enzyme to another, but there has been no experimental confirmation of this structure or the channeling. A structural investigation of enzyme organization within the Krebs cycle metabolon was accomplished by in vivo cross-linking and mass spectrometry. Eight Krebs cycle enzyme components were isolated upon chemical fixation, and interfacial residues between mitochondrial malate dehydrogenase, citrate synthase, and aconitase were identified. Using constraint protein docking, a low-resolution structure for the three-enzyme complex was achieved, as well as the two-fold symmetric octamer. Surface analysis showed formation of electrostatic channeling upon protein–protein association, which is the first structural evidence of substrate channeling in the Krebs cycle metabolon.
Co-reporter:David P. Hickey ; Matthew S. McCammant ; Fabien Giroud ; Matthew S. Sigman
Journal of the American Chemical Society 2014 Volume 136(Issue 45) pp:15917-15920
Publication Date(Web):October 28, 2014
DOI:10.1021/ja5098379
We demonstrate the complete electrochemical oxidation of the biofuel glycerol to CO2 using a hybrid enzymatic and small-molecule catalytic system. Combining an enzyme, oxalate oxidase, and an organic oxidation catalyst, 4-amino-TEMPO, we are able to electrochemically oxidize glycerol at a carbon electrode, while collecting up to as many as 16 electrons per molecule of fuel. Additionally, we investigate the anomalous electrocatalytic properties that allow 4-amino-TEMPO to be active under the acidic conditions that are required for oxalate oxidase to function.
Co-reporter:Yevgenia Ulyanova, Mary A. Arugula, Michelle Rasmussen, Erica Pinchon, Ulf Lindstrom, Sameer Singhal, and Shelley D. Minteer
ACS Catalysis 2014 Volume 4(Issue 12) pp:4289
Publication Date(Web):October 23, 2014
DOI:10.1021/cs500802d
Alkanes are attractive fuels for fuel cells due to their high energy density, but their use has not transitioned to biofuel cells. This paper discusses the development of a novel enzyme cascade utilizing alkane monooxygenase (AMO) and alcohol oxidase (AOx) to perform mediated bioelectrocatalytic oxidation of hexane and octane. This was then applied for the bioelectrocatalysis of the jet fuel JP-8, which was tested directly in an enzymatic biofuel cell to evaluate performance. The enzymatic catalysts were shown to be sulfur tolerant and produced power densities up to 3 mW/cm2 from native JP-8 without desulfurization as opposed to traditional metal catalysts, which require fuel preprocessing.Keywords: alcohol dehydrogenase; alcohol oxidase; alkane monooxygenase; alkane oxidation; bioelectrocatalysis; biofuel cells; JP-8
Co-reporter:Shuai Xu and Shelley D. Minteer
ACS Catalysis 2014 Volume 4(Issue 7) pp:2241
Publication Date(Web):June 2, 2014
DOI:10.1021/cs500442b
One of the main technological issues with enzymatic biofuel cells and biosensors is improving the electron transfer between the enzyme and the current collector to improve current densities. In this study, we show the use of a conducting polymer to mediate pyrroloquinoline quinone-dependent enzymatic bioelectrocatalysis. A self-doped polyaniline (PANi) film is electropolymerized on a Toray carbon paper electrode surface to covalently bond enzymes to this three-dimensional interface. Sulfonic acid groups are introduced into the PANi backbone structure to increase the polymer conductivity at neutral pH via a self-doping process, and the carboxyl groups can be activated to covalently bond to enzymes. The electropolymerization of 2-methoxyaniline-5-sulfonic acid and 3-aminobenzoic acid is optimized with respect to the rate of the bioelectrocatalytic conversion of enzyme substrates. Comparing this PANi conducting copolymer enzyme immobilization technique with the hydrophobically modified Nafion encapsulation-based enzyme immobilization method showed a 9.8-fold increase in current density.Keywords: bioelectrocatalysis; biofuel cell; conducting polymer; enzyme immobilization; polyaniline; PQQ-dependent dehydrogenases
Co-reporter:Michelle Rasmussen and Shelley D. Minteer
Physical Chemistry Chemical Physics 2014 vol. 16(Issue 32) pp:17327-17331
Publication Date(Web):03 Jul 2014
DOI:10.1039/C4CP02754J
Thylakoid membranes from spinach were separated into grana and stroma thylakoid fractions which were characterized by several methods (pigment content, protein gel electrophoresis, photosystem activities, and electron microscopy analysis) to confirm that the intact thylakoids were differentiated into the two domains. The results of photoelectrochemical experiments showed that stroma thylakoid electrodes generate photocurrents more than four times larger than grana thylakoids (51 ± 4 nA cm−2 compared to 11 ± 1 nA cm−2). A similar trend was seen in a bio-solar cell configuration with stroma thylakoids giving almost twice the current (19 ± 3 μA cm−2) as grana thylakoids (11 ± 2 μA cm−2) with no change in open circuit voltage.
Co-reporter:Dr. Fabien Giroud;Dr. David P. Hickey; David W. Schmidtke; Daniel T. Glatzhofer; Shelley D. Minteer
ChemElectroChem 2014 Volume 1( Issue 11) pp:1880-1885
Publication Date(Web):
DOI:10.1002/celc.201402162
Abstract
The utilization of carbon felt as the conductive material for the construction of a monosaccharide-based coin-cell biobattery is explored. Anthracene-modified carbon nanotubes were used at the positive electrode to preferentially orientate laccase for direct electron transfer during O2 reduction. A ferrocene-modified poly(ethylenimine) redox polymer was used to electrically communicate with either glucose oxidase or fructose dehydrogenase at the negative electrode. The use of carbon felt helped in the immobilization of a larger quantity of enzyme. Cathodic and anodic currents with carbon felt electrodes showed a three-fold and twofold increase, respectively, relative to the currents obtained with Toray paper materials. Bioelectrodes were assembled in a commercial coin-cell battery casing and were tested as possible biobatteries. This work presents the first time in which a traditional battery design is used for the performance evaluation of different biobatteries.
Co-reporter:Dr. Fabien Giroud;Dr. David P. Hickey; David W. Schmidtke; Daniel T. Glatzhofer; Shelley D. Minteer
ChemElectroChem 2014 Volume 1( Issue 11) pp:
Publication Date(Web):
DOI:10.1002/celc.201402338
Co-reporter:Shuai Xu and Shelley D. Minteer
ACS Catalysis 2013 Volume 3(Issue 8) pp:1756
Publication Date(Web):June 28, 2013
DOI:10.1021/cs400316b
To investigate the effect of the orientation of large and complex multi-subunit enzymes (MW > 50 kDa) on direct bioelectrocatalysis, we immobilized enzymes known to be capable of direct electron transfer (DET) via a site specific immobilization technique to form a monolayer of biocatalysts with a uniform orientation toward the gold electrode. Six recombinant pyrroloquinoline quinone-dependent aldehyde dehydrogenases (PQQ-AlDHs) were employed, where the enzymes had been labeled with six-histidine tags (His-tag) at the N- or C-terminus of each of the three subunits. His-tags were utilized as linking sites to perform site specific immobilization of PQQ-AlDHs. Results show that the orientation of multi-subunit enzymes can affect DET greatly by varying the electron tunneling distances. The favorable orientation allowing for a minimal heme c electron transfer distance showed a DET rate 6.6-fold higher than that with the orientation closest to the active site of the enzyme, while the unfavorable attachment to a nonelectroactive subunit showed no DET.Keywords: bioelectrocatalysis; direct electron transfer; enzyme orientation; PQQ-dependent dehydrogenases; quinohemoproteins
Co-reporter:David P. Hickey, Fabien Giroud, David W. Schmidtke, Daniel T. Glatzhofer, and Shelley D. Minteer
ACS Catalysis 2013 Volume 3(Issue 12) pp:2729
Publication Date(Web):October 18, 2013
DOI:10.1021/cs4003832
Biofuel cells provide a safe and renewable means of powering small electronic devices. In this work, we demonstrate a bioanode that is capable of extracting four electrons from a single molecule of sucrose by way of a three-enzyme cascade. Invertase, fructose dehydrogenase and glucose oxidase are immobilized in a ferrocene-modified linear poly(ethylenimine) (LPEI) hydrogel onto the surface of a carbon electrode. Fuel sources are generated in the polymer film by (1) hydrolyzing sucrose into fructose and glucose and then (2) electroenzymatically oxidizing fructose and glucose to produce a current response. A previously unreported synergistic effect is observed between glucose oxidase and fructose dehydrogenase that results in a current response that is considerably higher than expected. The newly described enzyme cascade generated 302 ± 57 μA/cm2 at 25 °C and 602 ± 62 μA/cm2 at 37 °C and when poised against an air breathing platinum cathode in a biofuel cell, the multienzyme-containing film generated 42 ± 15 μW/cm2 at 172 mV with a maximum current density of 344 ± 25 μA/cm2 in 100 mmol/L sucrose at 25 °C. This is the first example of an enzymatic biofuel cell that utilizes both fructose and glucose as oxidation fuel sources.Keywords: ferrocene; fructose dehydrogenase; glucose oxidase; invertase; poly(ethylenimine); redox polymer
Co-reporter:Alain Walcarius, Shelley D. Minteer, Joseph Wang, Yuehe Lin and Arben Merkoçi
Journal of Materials Chemistry A 2013 vol. 1(Issue 38) pp:4878-4908
Publication Date(Web):23 Jul 2013
DOI:10.1039/C3TB20881H
Recent years have faced stimulating developments in the functionalization of electrode surfaces with biological materials, notably due to the significant input of nanosciences and nanotechnology. In this review (over 450 references), we are discussing the interest of both nano-objects (metal nanoparticles and quantum dots, carbon nanotubes and graphene) and nano-engineered and/or nanostructured materials (template-based materials, advanced organic polymers) for the rational design of bio-functionalized electrodes and related (bio)sensing systems. The attractiveness of such nanomaterials relies not only on their ability to act as effective immobilization matrices, which are, e.g., likely to enhance the long-term stability of bioelectrochemical devices, but also on their intrinsic and unique features (large surface areas, electrocatalytic properties, controlled morphology and structure, possible use as labels) that can be advantageously combined with the functioning of biomolecules, thus contributing to improved bioelectrode performance in terms of sensitivity and selectivity (enzymatic biosensors, DNA sensors, immunosensors and cell sensors) or power (biofuel cells).
Co-reporter:Sidney Aquino Neto, Emily L. Suda, Shuai Xu, Matthew T. Meredith, Adalgisa R. De Andrade, Shelley D. Minteer
Electrochimica Acta 2013 Volume 87() pp:323-329
Publication Date(Web):1 January 2013
DOI:10.1016/j.electacta.2012.09.052
This paper compares the performance of a DET (direct electron transfer) bioanode containing both PQQ-ADH (pyrroloquinoline quinone-dependent alcohol dehydrogenase) and PQQ-AldDH (PQQ-dependent aldehyde dehydrogenase) immobilized onto different modified electrode surfaces employing either a tetrabutylammonium (TBAB)-modified Nafion® membrane polymer or polyamidoamine (PAMAM) dendrimers for the enzyme immobilization. The electrochemical characterization showed that the prepared bioelectrodes were able to undergo DET onto glassy carbon surface in the presence as well as the absence of multi-walled carbon nanotubes (MWCNTs); also, in the latter case a relevant shift in the oxidation peak of about 180 mV vs. saturated calomel electrode (SCE) was observed. A very similar redox potential was achieved with the self-assembled bioelectrode prepared onto modified-gold surfaces with dendrimers, indicating that both methodologies provide an environment that enables the PQQ-enzymes to undergo DET. The biofuel cell tests confirmed the ease of the DET process and the enhanced performance in the presence of the carbon nanotubes. Considering the bioanodes prepared with PAMAM dendrimers, the power density values vary from 19.4 μW cm−2 without MWCNTs to 25.7 μW cm−2 in the presence of MWCNTs. Similarly, with the bioanodes prepared with the TBAB-modified-Nafion® polymer, the results indicate power densities of 27.9 and 38.4 μW cm−2 respectively. These electrode modifications represent effective methods for immobilization and direct electrical connection of quinohemoproteins to electrode surfaces.
Co-reporter:Fabien Giroud, Shelley D. Minteer
Electrochemistry Communications 2013 Volume 34() pp:157-160
Publication Date(Web):September 2013
DOI:10.1016/j.elecom.2013.06.006
•Pyrene derivatives are functionalized with anthracene groups.•The pyrene derivatives are immobilized onto MWCNTs via π-π interactions.•Laccase direct bioelectrocatalysis is improved via anthracene modified pyrene.Enhancement of direct bioelectrocatalysis of dioxygen reduction with laccase has been investigated using π-electron rich compounds, such as anthracene, for docking the laccase active site in close proximity to the electrode. These molecules have been shown to promote direct bioelectrocatalysis by orienting the enzyme to undergo fast, direct electron transfer. In this study, pyrene moieties have been covalently grafted to anthracene groups to be able to functionalize carbon nanotube walls to increase the number of binding sites on nanotubes for laccase. Current densities were compared to unmodified pyrene immobilized by non-covalent interactions on the hydroxylated carbon nanotubes (MWCNT-OH). The presence of pyrene derivatives leads to higher current density than regular MWCNT-OH. In both configurations, the covalent grafting of the anthracene group to pyrene improved electrocatalytic signals. Under normal aerated conditions, 1-pyrenemethanol-modified and 1-aminopyrene-modified electrodes produced 81.4 ± 14.5 μA/cm2 and 62.5 ± 4.9 μA/cm2, respectively, while for derivatives 1 and 2, current densities produced 186.4 ± 10.4 μA/cm2 and 153.0 ± 5.2 μA/cm2. Once characterized, the best pyrene-based bioelectrodes were used with laccase as a biocathode and combined with a glucose oxidase (GOx)-based bioanode to form glucose/O2 biofuel cells.
Co-reporter:Garett G. W. Lee and Shelley D. Minteer
ACS Sustainable Chemistry & Engineering 2013 Volume 1(Issue 3) pp:359
Publication Date(Web):January 24, 2013
DOI:10.1021/sc300162d
Efforts to reduce the cost of production and reduce hazards associated with catalyst production, as well as improve catalytic performance of fuel cells, is increasingly gaining attention in chemistry, materials science, and chemical engineering. Costs, particularly of the catalyst system, are incurred in each step of production, including raw materials and their processing, catalyst preparation, and immobilization on electrodes. Here is described a low-temperature neutral pH method of electrodepositing a manganese oxygen-reducing electrocatalyst for alkaline fuel cell systems. The analysis emphasizes the effects of anions used during the deposition process and their effect on catalytic performance.Keywords: Alkaline; Electrocatalyst; Electrochemistry; Fuel cell; Oxygen reduction reaction
Co-reporter:Michelle Rasmussen, Alexander Shrier and Shelley D. Minteer
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 23) pp:9062-9065
Publication Date(Web):13 May 2013
DOI:10.1039/C3CP51813B
Thylakoid membranes have previously been used for electrochemical solar energy conversion, but the current output and open circuit voltage are low, in part due to limitations of the cathode. In this paper, a thylakoid bioanode and laccase biocathode were combined in the construction of a bio-solar cell capable of light-induced generation of electrical power. This two-compartment cell showed a greater than 5-fold increase in short circuit current density and an open circuit voltage 0.275 V larger than that of a thylakoid bio-solar cell incorporating an air-breathing Pt cathode. The electrodes were then tested in several solutions of varying pH to evaluate the possibility of constructing a compartment-less bio-solar cell. This membrane-less cell, operating at pH 5.5, generated a short circuit photocurrent density of 14.0 ± 1.8 μA cm−2 which is 25% larger than the two-compartment cell and a similar open circuit voltage of 0.720 ± 0.018 V.
Co-reporter:Robert L. Arechederra, Abdul Waheed, William S. Sly, Claudiu T. Supuran, Shelley D. Minteer
Bioorganic & Medicinal Chemistry 2013 Volume 21(Issue 6) pp:1544-1548
Publication Date(Web):15 March 2013
DOI:10.1016/j.bmc.2012.06.053
Obesity is quickly becoming an increasing problem in the developed world. One of the major fundamental causes of obesity and diabetes is mitochondria dysfunction due to faulty metabolic pathways which alter the metabolic substrate flux resulting in the development of these diseases. This paper examines the role of mitochondrial carbonic anhydrase (CA) isozymes in the metabolism of pyruvate, acetate, and succinate when specific isozyme inhibitors are present. Using a sensitive electrochemical approach of wired mitochondria to analytically measure metabolic energy conversion, we determine the resulting metabolic difference after addition of an inhibitory compound. We found that certain sulfonamide analogues displayed broad spectrum inhibition of metabolism, where others only had significant effect on some metabolic pathways. Pyruvate metabolism always displayed the most dramatically affected metabolism by the sulfonamides followed by fatty acid metabolism, and then finally succinate metabolism. This allows for the possibility of using designed sulfonamide analogues to target specific mitochondrial CA isozymes in order to subtly shift metabolism and glucogenesis flux to treat obesity and diabetes.
Co-reporter:Michelle Rasmussen and Shelley D. Minteer
Analytical Methods 2013 vol. 5(Issue 5) pp:1140-1144
Publication Date(Web):17 Jan 2013
DOI:10.1039/C3AY26488B
A self-powered biosensor has been developed for the detection of herbicides in water. It consists of a bio-solar cell incorporating thylakoid membranes at the bioanode for direct photoelectrocatalysis with an air-breathing platinum cathode. The biosolar cell produces power in the presence of light, but inhibition of photosystems of the thylakoids by herbicides leads to a decrease in current output. This current decrease can be used to determine herbicide concentration. This sensor was able to detect several commercial herbicides, including: atrazine, bromacil, and diuron with a linear response up to concentrations of ∼15 μg L−1 and limits of detection (LOD) below 0.5 μg L−1, which are below the EPA limits.
Co-reporter:Fabien Giroud, Tera A. Nicolo, Sara J. Koepke, Shelley D. Minteer
Electrochimica Acta 2013 110() pp: 112-119
Publication Date(Web):
DOI:10.1016/j.electacta.2013.02.087
Co-reporter:Fei Wu and Shelley D. Minteer
Biomacromolecules 2013 Volume 14(Issue 8) pp:
Publication Date(Web):July 12, 2013
DOI:10.1021/bm400569k
Sequential metabolic enzymes can form supramolecular complexes named metabolons in vivo through enzyme–enzyme association or aggregation to facilitate efficient substrate channeling. By separately labeling enzymes with lysine-targeting carboxylic acid succinimidyl ester fluorophores of distinct excitation wavelengths, this research presents a quantitative study of polymer-entrapment-induced in vitro multi-enzyme aggregation from three Krebs cycle enzymes using Förster resonance energy transfer (FRET) to find potential polymer materials for immobilizing enzyme cascades and inducing the metabolon biomimic formation on electrodes. The effect of hydrophobic modification of linear polyethylenimine, Nafion, and chitosan polymers on metabolon formation has been investigated through photobleaching FRET imaging in addition to traditional steady-state fluorescence spectroscopy. By partially destroying FRET acceptors of longer excitation wavelength, increased fluorescence from dequenched donors of shorter excitation wavelength was measured and enzyme interactions in terms of energy-transfer efficiencies were mapped point by point. Results show that trimethyloctadecylammonium-modified Nafion works best in inducing multi-enzyme aggregation and exhibits a promising future in immobilized metabolon biomimics with the most uniform enzyme organization, as indicated by the protein distance distribution.
Co-reporter:Shelley D. Minteer, Plamen Atanassov, Heather R. Luckarift, Glenn R. Johnson
Materials Today 2012 Volume 15(Issue 4) pp:166-173
Publication Date(Web):April 2012
DOI:10.1016/S1369-7021(12)70070-6
Major improvements in biological fuel cells over the last ten years have been the result of the development and application of new materials. These new materials include: nanomaterials, such as nanotubes and graphene, that improve the electron transfer between the biocatalyst and electrode surface; materials that provide improved stability and immobilization of biocatalysts; materials that increase the conductivity and surface area of the electrodes; and materials that aid facile mass transport. With a focus on enzymatic biological fuel cell technology, this brief review gives an overview of the latest developments in each of these material science areas and describes how this progress has improved the performance of biological fuel cells to yield a feasible technology.
Co-reporter:Shuai Xu and Shelley D. Minteer
ACS Catalysis 2012 Volume 2(Issue 1) pp:91
Publication Date(Web):December 6, 2011
DOI:10.1021/cs200523s
Glucose has been widely studied as a fuel in biofuel cells because it not only is abundant in nature and in the bloodstream but also demonstrates low volatility, is nontoxic, and is inexpensive. Those qualities coupled with its relatively high energy density qualify glucose as a promising fuel. However, one key to efficient use of this substrate as fuel is the ability to oxidize glucose to CO2 and convert, more efficiently, the chemical energy released upon the redox reactions to electrical power. Most glucose biofuel cells in literature only oxidize glucose to gluconolactone. In this paper, we report the development of a six-enzyme cascade bioanode containing pyrroloquinoline quinone-dependent enzymes extracted from Gluconobacter sp., aldolase from Sulfolobus solfataricus and oxalate oxidase from barley to sequentially oxidize glucose to carbon dioxide through a synthetic minimal metabolic pathway. This bioanode is also capable of performing direct electron transfer to carbon electrode surfaces and eliminates the need for mediators.Keywords: bioanodes; bioelectrocatalysis; biofuel cell; enzyme cascades; glucose metabolism;
Co-reporter:Michael J. Moehlenbrock, Matthew T. Meredith, and Shelley D. Minteer
ACS Catalysis 2012 Volume 2(Issue 1) pp:17
Publication Date(Web):November 8, 2011
DOI:10.1021/cs200482v
Enzymatic biofuel cells and bioelectrochemical sensors are often limited in performance because of their inability to utilize all of the energy confined in chemical bonds of complex molecules. Multi-enzyme cascade catalysis provides a means to remedy this limitation, but efficiencies of such electrodes can be further enhanced by improving interenzyme substrate mass transport. This consideration is demonstrated to be advantageous in biological systems, as displayed by nearly ubiquitous organization of sequential enzymes in natural metabolic pathways. This sequential organization, termed a metabolon, is examined in this work for a two-enzyme pentose phosphate pathway bioelectrode for the oxidation of glucose. This two-enzyme electrode is compared with a single enzyme, glucose dehydrogenase, and demonstrates increased performance. In addition, increases in efficiency are demonstrated through the creation of a synthetic two-enzyme metabolon versus randomly suspended enzymes immobilized within a hydrogel matrix.Keywords: biofuel cell; glucose biosensor; metabolon; pentose phosphate pathway; substrate channeling;
Co-reporter:Garett G. W. Lee, Johna Leddy and Shelley D. Minteer
Chemical Communications 2012 vol. 48(Issue 98) pp:11972-11974
Publication Date(Web):22 Oct 2012
DOI:10.1039/C2CC36965F
The addition of a magnetic composite membrane to a traditional nickel electrocatalyst was employed to increase the methanol and n-butanol electrocatalysis in alkaline media.
Co-reporter:Lindsey N. Pelster, Shelley D. Minteer
Electrochimica Acta 2012 Volume 82() pp:214-217
Publication Date(Web):1 November 2012
DOI:10.1016/j.electacta.2011.11.121
Electron transport chain complexes are critical to metabolism in living cells. Ubiquinol-cytochrome c reductase (Complex III) is responsible for carrying electrons from ubiquinol to cytochrome c, but the complex has not been evaluated electrochemically. This work details the bioelectrochemistry of ubiquinol-cytochrome c reductase of the electron transport chain of tuber mitochondria. The characterization of the electrochemistry of this enzyme is investigated in carboxylated multi-walled carbon nanotube/tetrabutyl ammonium bromide-modified Nafion® modified glassy carbon electrodes by cyclic voltammetry. Increasing concentrations of cytochrome c result in a catalytic response from the active enzyme in the nanotube sandwich. The experiments show that the enzyme followed Michaelis–Menten kinetics with a Km for the immobilized enzyme of 2.97 (±0.11) × 10−6 M and a Vmax of 6.31 (±0.82) × 10−3 μmol min−1 at the electrode, but the Km and Vmax values decreased compared to the free enzyme in solution, which is expected for immobilized redox proteins. This is the first evidence of ubiquinol-cytochrome c reductase bioelectrocatalysis.Highlights► The electron transport chain is important to the understanding of metabolism in the living cell. ► Ubiquinol-cytochrome c reductase is a membrane bound complex of the electron transport chain (Complex III). ► The paper details the first bioelectrochemical characterization of ubiquinol-cytochrome c reductase at an electrode.
Co-reporter:Matthew T. Meredith, Fabien Giroud, Shelley D. Minteer
Electrochimica Acta 2012 Volume 72() pp:207-214
Publication Date(Web):30 June 2012
DOI:10.1016/j.electacta.2012.04.017
The development of new, efficient bioelectrodes is important to the improvement of biosensor and biofuel cell technology. NAD-dependent dehydrogenase enzymes represent a diverse field of oxidoreductase enzymes that can be used to create unique biosensors and biofuel cells, but require electrocatalysts to oxidize NADH in order to harvest the electrons efficiently from fuel oxidation. This study presents a new methodology for the co-immobilization of dehydrogenase enzymes, azine-based NADH electrocatalysts, carbon nanotubes, and polymer hydrogels. The easy “one-pot” mixing and casting procedure is shown to produce electrodes that can electro-oxidize NADH at low potentials. In situ electropolymerization of the azine dyes within the composites is shown to improve NADH sensitivity, but harms enzyme activity. Biosensors and biofuel cells are constructed with a model enzyme, glucose dehydrogenase, to show the application of this system in a glucose biosensor and biofuel cell. Glucose biosensors produced limiting current densities of 400 μA/cm2 and glucose/air-breathing biofuel cells produced power densities slightly greater than 100 μW/cm2.
Co-reporter:Stephanie L. Maltzman and Shelley D. Minteer
Analytical Methods 2012 vol. 4(Issue 5) pp:1202-1206
Publication Date(Web):12 Mar 2012
DOI:10.1039/C2AY05946K
The mode of action of many pesticides is to inhibit electron transport chain complexes of the mitochondria of living cells. Therefore, this paper investigated whether mitochondrial modified electrodes could be utilized to electrochemically sense pesticides. This paper details the fabrication of a two electrode electrochemical cell utilizing a mitochondrial modified bioanode in pyruvate solution and an air-breathing platinum cathode. 2,4-Dichlorophenoxyacetic acid, atrazine, paraquat, parathion, and permethrin were studied as pesticides. Pesticide detection was performed by background subtracted linear scan voltammetry of the two-electrode mitochondrial biofuel cell before and after the addition of pesticide. Pesticides were shown to attenuate pyruvate bioelectrocatalysis for all pesticides studied. A concentration study was performed with atrazine and showed a sigmoidal inhibition response with concentration and the ability to detect concentrations at the EPA maximum contaminant level of 3 ppb.
Co-reporter:Shelley D. Minteer
Topics in Catalysis 2012 Volume 55( Issue 16-18) pp:1157-1161
Publication Date(Web):2012 November
DOI:10.1007/s11244-012-9898-8
This review details the use of nanomaterials to improve bioelectrocatalysis for biosensor and biological fuel cell applications. Different types of bioelectrocatalysts are described as well as different types of nanomaterials for improving the rate of bioelectrocatalysis, as well as the active surface area of the electrodes.
Co-reporter:Matthew T. Meredith, Michael Minson, David Hickey, Kateryna Artyushkova, Daniel T. Glatzhofer, and Shelley D. Minteer
ACS Catalysis 2011 Volume 1(Issue 12) pp:1683
Publication Date(Web):October 21, 2011
DOI:10.1021/cs200475q
The development of new methods to facilitate direct electron transfer (DET) between enzymes and electrodes is of much interest because of the desire for stable biofuel cells that produce significant amounts of power. In this study, hydroxylated multiwalled carbon nanotubes (MWCNTs) were covalently modified with anthracene groups to help orient the active sites of laccase to allow for DET. The onset of the catalytic oxygen reduction current for these biocathodes occurred near the potential of the T1 active site of laccase, and optimized biocathodes produced background-subtracted current densities up to 140 μA/cm2. Potentiostatic and galvanostatic stability measurements of the biocathodes revealed losses of 25% and 30%, respectively, after 24 h of constant operation. Finally, the novel biocathodes were utilized in biofuel cells employing two different anodic enzymes. A compartmentalized cell using a mediated glucose oxidase anode produced an open circuit voltage of 0.819 ± 0.022 V, a maximum power density of 56.8 (±1.8) μW/cm2, and a maximum current density of 205.7 (±7.8) μA/cm2. A compartment-less cell using a DET fructose dehydrogenase anode produced an open circuit voltage of 0.707 ± 0.005 V, a maximum power density of 34.4 (±2.7) μW/cm2, and a maximum current density of 201.7 (±14.4) μA/cm2.Keywords: anthracene; bioelectrocatalysis; direct electron transfer; laccase; oxygen reduction reaction;
Co-reporter:Robert L. Arechederra, Abdul Waheed, William S. Sly and Shelley D. Minteer
Analyst 2011 vol. 136(Issue 18) pp:3747-3752
Publication Date(Web):21 Jul 2011
DOI:10.1039/C1AN15370F
In the continual search of new therapeutics, many possible drug candidates are excluded, because they are found to negatively affect mitochondrial function. We have developed an approach for directly, electrochemically assaying mitochondrial metabolic activity as a function of metabolic substrate to determine drug toxicity. By wiring mouse mitochondria to a carbon electrode surface, electrons can be intercepted before they reach Complex IV, the terminal step of electron transport chain. The electrons are rerouted, to a separate electrode of the electrochemical cell, the cathode. This allows for the direct measurement of electrical current and potential of the mitochondria during their oxidation of substrates such as pyruvate and fatty acids when there are different concentrations of drug present. This analytical technique has been shown to reliably assay several classical mitochondrial toxins and exhibits potential for the further development of a drug candidate screening technique, as well as other applications where the quantitative study of mitochondrial dysfunction is important.
Co-reporter:Shelley D. Minteer
Biochimica et Biophysica Acta (BBA) - Bioenergetics (May 2016) Volume 1857(Issue 5) pp:621-624
Publication Date(Web):May 2016
DOI:10.1016/j.bbabio.2015.08.008
Co-reporter:Krysti L. Knoche, Erika Aoyama, Kamrul Hasan, Shelley D. Minteer
Electrochimica Acta (1 April 2017) Volume 232() pp:
Publication Date(Web):1 April 2017
DOI:10.1016/j.electacta.2017.02.148
Current ammonia production methods are costly and environmentally detrimental. Biological nitrogen fixation has implications for low cost, environmentally friendly ammonia production. It has been shown that electrochemical stimulation increases the ammonia output of the cyanobacteria SA-1 mutant of Anabaena variabilis, but the mechanism of bioelectrocatalysis has been unknown. Here, the mechanism of electrostimulated biological ammonia production is investigated by immobilization of the cyanobacteria with polyvinylamine on indium tin oxide (ITO) coated polyethylene. Cyclic voltammetry is performed in the absence and presence of various substrates and with nitrogenase repressed and nitrogenase derepressed cells to study mechanism, and cyclic voltammetry and UV–vis spectroscopy are used to identify redox moieties in the spent electrolyte. A bioelectrocatalytic signal is observed for nitrogenase derepressed A. variabilis SA-1 in the presence of N2 and light. Results indicate that the redox protein ferredoxin mediates electron transfer between nitrogenase and the electrode to stimulate ammonia production.
Co-reporter:Sofiene Abdellaoui, Madelaine Seow Chavez, Ivana Matanovic, Andrew R. Stephens, Plamen Atanassov and Shelley D. Minteer
Chemical Communications 2017 - vol. 53(Issue 39) pp:NaN5371-5371
Publication Date(Web):2017/04/07
DOI:10.1039/C7CC01027C
Glycerol is a common fuel considered for bioenergy applications. Computational docking studies were performed on formate dehydrogenase from Candida boidinii (cbFDH) that showed that mesoxalate can bind to the buried active site of the holo form predicting that mesoxalate, a byproduct of glycerol oxidation, may act as its substrate. Spectroscopic assays and characterization by HPLC and GC/TCD have shown for the first time that cbFDH can act as a decarboxylase with mesoxalate. From this assessment, cbFDH was combined with NH2-TEMPO to form a novel hybrid anode to oxidize glycerol to carbon dioxide at near-neutral pH.
Co-reporter:Timothy Quah, Ross D. Milton, Sofiene Abdellaoui and Shelley D. Minteer
Chemical Communications 2017 - vol. 53(Issue 60) pp:NaN8414-8414
Publication Date(Web):2017/06/09
DOI:10.1039/C7CC03842A
Diaphorase and a benzylpropylviologen redox polymer were combined to create a bioelectrode that can both oxidize NADH and reduce NAD+. We demonstrate how bioelectrocatalytic NAD+/NADH inter-conversion can transform a glucose/O2 enzymatic fuel cell (EFC) with an open circuit potential (OCP) of 1.1 V into an enzymatic redox flow battery (ERFB), which can be rapidly recharged by operation as an EFC.
Co-reporter:David P. Hickey, Krysti L. Knoche, Kelan Albertson, Carolina Castro, Ross D. Milton and Shelley D. Minteer
Chemical Communications 2016 - vol. 52(Issue 90) pp:NaN13302-13302
Publication Date(Web):2016/10/20
DOI:10.1039/C6CC07215A
Here, we demonstrate the use of phospholipid micelles to enhance O2 concentrations by two-fold at the surface of a bilirubin oxidase biocathode. Specifically, 1,2-diarachidoyl-sn-glycero-3-phosphocholine was used in a glucose enzymatic fuel cell to limit power losses due to O2 transport, even in a quiescent solution.
Co-reporter:Yaovi Holade, David P. Hickey and Shelley D. Minteer
Journal of Materials Chemistry A 2016 - vol. 4(Issue 43) pp:NaN17162-17162
Publication Date(Web):2016/10/14
DOI:10.1039/C6TA08288B
Direct growth of hierarchical micro/nanostructured metal arrays on a 3D substrate is a powerful tool to enhance the catalytic efficiency of metal particles towards a wide range of substrates. In this contribution, we demonstrate a novel and versatile method for growing anisotropic microstructures directly onto a 3D carbon paper electrode, using Au, Pd and Pt nanoparticles as elementary building blocks. It was determined that halides play a crucial role in the morphology of synthesized Au particles, leading to either complex flower-like rough surfaces (exhibiting high catalytic activity) or featureless smooth surfaces (exhibiting low catalytic activity). Of the three metal materials studied, the Pt decorated carbon paper (Pt@carbon) material exhibits a high electrocatalytic activity toward the oxygen reduction reaction in an alkaline medium. We demonstrate that this new Pt material can operate as a cathode in an alkaline glucose fuel cell exhibiting outstanding peak power density of 2–3 mW cm−2 (using an anode of Au@carbon or Pt@carbon at room temperature and low metal loading without any fuel circulation). This newly described fabrication approach allows for the rational control of metallic particle growth, paving a new way towards materials with regulated surface roughness allowing for tuneable physical, optical and catalytic properties.
Co-reporter:
Analytical Methods (2009-Present) 2012 - vol. 4(Issue 5) pp:
Publication Date(Web):
DOI:10.1039/C2AY05946K
The mode of action of many pesticides is to inhibit electron transport chain complexes of the mitochondria of living cells. Therefore, this paper investigated whether mitochondrial modified electrodes could be utilized to electrochemically sense pesticides. This paper details the fabrication of a two electrode electrochemical cell utilizing a mitochondrial modified bioanode in pyruvate solution and an air-breathing platinum cathode. 2,4-Dichlorophenoxyacetic acid, atrazine, paraquat, parathion, and permethrin were studied as pesticides. Pesticide detection was performed by background subtracted linear scan voltammetry of the two-electrode mitochondrial biofuel cell before and after the addition of pesticide. Pesticides were shown to attenuate pyruvate bioelectrocatalysis for all pesticides studied. A concentration study was performed with atrazine and showed a sigmoidal inhibition response with concentration and the ability to detect concentrations at the EPA maximum contaminant level of 3 ppb.
Co-reporter:
Analytical Methods (2009-Present) 2013 - vol. 5(Issue 5) pp:NaN1144-1144
Publication Date(Web):2013/01/17
DOI:10.1039/C3AY26488B
A self-powered biosensor has been developed for the detection of herbicides in water. It consists of a bio-solar cell incorporating thylakoid membranes at the bioanode for direct photoelectrocatalysis with an air-breathing platinum cathode. The biosolar cell produces power in the presence of light, but inhibition of photosystems of the thylakoids by herbicides leads to a decrease in current output. This current decrease can be used to determine herbicide concentration. This sensor was able to detect several commercial herbicides, including: atrazine, bromacil, and diuron with a linear response up to concentrations of ∼15 μg L−1 and limits of detection (LOD) below 0.5 μg L−1, which are below the EPA limits.
Co-reporter:Sofiene Abdellaoui, Ross D. Milton, Timothy Quah and Shelley D. Minteer
Chemical Communications 2016 - vol. 52(Issue 6) pp:NaN1150-1150
Publication Date(Web):2015/11/24
DOI:10.1039/C5CC09161F
Electron mediation between NAD-dependent enzymes using quinone moieties typically requires the use of a diaphorase as an intermediary enzyme. The ability for a naphthoquinone redox polymer to independently oxidize enzymatically-generated NADH is demonstrated for application to glucose/O2 enzymatic fuel cells.
Co-reporter:Fei Wu, Lindsey N. Pelster and Shelley D. Minteer
Chemical Communications 2015 - vol. 51(Issue 7) pp:NaN1247-1247
Publication Date(Web):2014/11/28
DOI:10.1039/C4CC08702J
Dynamics of metabolon formation in mitochondria was probed by studying diffusional motion of two sequential Krebs cycle enzymes in a microfluidic channel. Enhanced directional co-diffusion of both enzymes against a substrate concentration gradient was observed in the presence of intermediate generation. This reveals a metabolite directed compartmentation of metabolic pathways.
Co-reporter:Khiem Van Nguyen and Shelley D. Minteer
Chemical Communications 2015 - vol. 51(Issue 66) pp:NaN13073-13073
Publication Date(Web):2015/07/06
DOI:10.1039/C5CC04810A
We report the usage of DNA hydrogels for enzyme entrapment in an enzymatic biobattery. With the recent advancements in DNA nanotechnology, the incorporation of DNA materials to bioelectrocatalytic electrodes holds great promise to improve the performance of bioelectrocatalysis-based devices.
Co-reporter:Garett G. W. Lee, Johna Leddy and Shelley D. Minteer
Chemical Communications 2012 - vol. 48(Issue 98) pp:NaN11974-11974
Publication Date(Web):2012/10/22
DOI:10.1039/C2CC36965F
The addition of a magnetic composite membrane to a traditional nickel electrocatalyst was employed to increase the methanol and n-butanol electrocatalysis in alkaline media.
Co-reporter:Ross D. Milton, David P. Hickey, Sofiene Abdellaoui, Koun Lim, Fei Wu, Boxuan Tan and Shelley D. Minteer
Chemical Science (2010-Present) 2015 - vol. 6(Issue 8) pp:NaN4875-4875
Publication Date(Web):2015/06/08
DOI:10.1039/C5SC01538C
Enzymatic fuel cells (EFCs) are devices that can produce electrical energy by enzymatic oxidation of energy-dense fuels (such as glucose). When considering bioanode construction for EFCs, it is desirable to use a system with a low onset potential and high catalytic current density. While these two properties are typically mutually exclusive, merging these two properties will significantly enhance EFC performance. We present the rational design and preparation of an alternative naphthoquinone-based redox polymer hydrogel that is able to facilitate enzymatic glucose oxidation at low oxidation potentials while simultaneously producing high catalytic current densities. When coupled with an enzymatic biocathode, the resulting glucose/O2 EFC possessed an open-circuit potential of 0.864 ± 0.006 V, with an associated maximum current density of 5.4 ± 0.5 mA cm−2. Moreover, the EFC delivered its maximum power density (2.3 ± 0.2 mW cm−2) at a high operational potential of 0.55 V.
Co-reporter:Alain Walcarius, Shelley D. Minteer, Joseph Wang, Yuehe Lin and Arben Merkoçi
Journal of Materials Chemistry A 2013 - vol. 1(Issue 38) pp:NaN4908-4908
Publication Date(Web):2013/07/23
DOI:10.1039/C3TB20881H
Recent years have faced stimulating developments in the functionalization of electrode surfaces with biological materials, notably due to the significant input of nanosciences and nanotechnology. In this review (over 450 references), we are discussing the interest of both nano-objects (metal nanoparticles and quantum dots, carbon nanotubes and graphene) and nano-engineered and/or nanostructured materials (template-based materials, advanced organic polymers) for the rational design of bio-functionalized electrodes and related (bio)sensing systems. The attractiveness of such nanomaterials relies not only on their ability to act as effective immobilization matrices, which are, e.g., likely to enhance the long-term stability of bioelectrochemical devices, but also on their intrinsic and unique features (large surface areas, electrocatalytic properties, controlled morphology and structure, possible use as labels) that can be advantageously combined with the functioning of biomolecules, thus contributing to improved bioelectrode performance in terms of sensitivity and selectivity (enzymatic biosensors, DNA sensors, immunosensors and cell sensors) or power (biofuel cells).
Co-reporter:Michelle Rasmussen and Shelley D. Minteer
Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 32) pp:NaN17331-17331
Publication Date(Web):2014/07/03
DOI:10.1039/C4CP02754J
Thylakoid membranes from spinach were separated into grana and stroma thylakoid fractions which were characterized by several methods (pigment content, protein gel electrophoresis, photosystem activities, and electron microscopy analysis) to confirm that the intact thylakoids were differentiated into the two domains. The results of photoelectrochemical experiments showed that stroma thylakoid electrodes generate photocurrents more than four times larger than grana thylakoids (51 ± 4 nA cm−2 compared to 11 ± 1 nA cm−2). A similar trend was seen in a bio-solar cell configuration with stroma thylakoids giving almost twice the current (19 ± 3 μA cm−2) as grana thylakoids (11 ± 2 μA cm−2) with no change in open circuit voltage.
Co-reporter:Michelle Rasmussen, Alexander Shrier and Shelley D. Minteer
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 23) pp:NaN9065-9065
Publication Date(Web):2013/05/13
DOI:10.1039/C3CP51813B
Thylakoid membranes have previously been used for electrochemical solar energy conversion, but the current output and open circuit voltage are low, in part due to limitations of the cathode. In this paper, a thylakoid bioanode and laccase biocathode were combined in the construction of a bio-solar cell capable of light-induced generation of electrical power. This two-compartment cell showed a greater than 5-fold increase in short circuit current density and an open circuit voltage 0.275 V larger than that of a thylakoid bio-solar cell incorporating an air-breathing Pt cathode. The electrodes were then tested in several solutions of varying pH to evaluate the possibility of constructing a compartment-less bio-solar cell. This membrane-less cell, operating at pH 5.5, generated a short circuit photocurrent density of 14.0 ± 1.8 μA cm−2 which is 25% larger than the two-compartment cell and a similar open circuit voltage of 0.720 ± 0.018 V.
Co-reporter:Khiem Van Nguyen and Shelley D. Minteer
Chemical Communications 2015 - vol. 51(Issue 23) pp:NaN4784-4784
Publication Date(Web):2015/02/11
DOI:10.1039/C4CC10250A
We present here the construction of a DNA biosensor based on a tubular micromotor that only produces motion-based signal in the presence of DNA target. This “turn on” characteristic of the sensor is achieved by the addition of Pt nanoparticle-DNA conjugate as the motion-inducing catalyst for the micromotors through DNA hybridization. Our work potentially offers new design strategies for motion-based biosensors with higher specificity.
Co-reporter:Sofiene Abdellaoui, David P. Hickey, Andrew R. Stephens and Shelley D. Minteer
Chemical Communications 2015 - vol. 51(Issue 76) pp:NaN14333-14333
Publication Date(Web):2015/08/10
DOI:10.1039/C5CC06131H
The complete electro-oxidation of glycerol to CO2 is performed through an oxidation cascade using a hybrid catalytic system combining a recombinant enzyme, oxalate decarboxylase from Bacillus subtilis, and an organic oxidation catalyst, 4-amino-TEMPO. This system is capable of electrochemically oxidizing glycerol at a carbon electrode collecting all 14 electrons per molecule.
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