| 1. |
- Antiochia, Riccarda, et al.
(författare)
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Composite Material Based on Macroporous Polyaniline and Osmium Redox Complex for Biosensor Development
- 2014
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Ingår i: Electroanalysis. - : Wiley. - 1040-0397. ; 26:7, s. 1623-1630
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Tidskriftsartikel (refereegranskat)abstract
- Here the feasibility of layers based on the conducting polymer polyaniline (PANI) as component of glucose biosensors using glucose oxidase (GOx) as enzyme and [Os(bpy)(2)(4-aminomethylpyridine)Cl]PF6 (OsCmplx) as electrochemical mediator, is evaluated. Particularly, PANI was employed to obtain a nanostructured macroporous material (m-PANI) around polystyrene nanoparticles taken as template and the mediator was co-immobilized during the polymerizing procedure. The GOx biosensor based on OsCmplx modified m-PANI provides a linear response to glucose concentration in the range 5 up to 65 mM with a sensitivity of 3.54 mu A/mM/cm(2) (on a projected geometric area=0.07 cm(2)), an LOD of 0.8 mM and a good precision (%RSD <= 7, n=5); the biosensor is stable showing a decrease of 10% to the value of the sensitivity after 15 days of use and of about 50% after 40 days.
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| 2. |
- Aslan, Sema, et al.
(författare)
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Development of a Bioanode for Microbial Fuel Cells Based on the Combination of a MWCNT-Au-Pt Hybrid Nanomaterial, an Osmium Redox Polymer and Gluconobacter oxydans DSM 2343 Cells
- 2017
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Ingår i: ChemistrySelect. - : Wiley. - 2365-6549. ; 2:36, s. 12034-12040
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Tidskriftsartikel (refereegranskat)abstract
- In this work, a carbon felt electrode (CFE) was modified with a multiwalled carbon nanotube-gold-platinum (MWCNT-Au-Pt) hybrid nanomaterial and integrated with an osmium redox polymer (OsRP, [Os(2, 2’-bipyridine)2(poly-vinylimidazole)10Cl]Cl) and Gluconobacter oxydans DSM 2343 (G. oxydans) cells. The developed electrode was used as the bioanode in a 5.0 mM K3Fe(CN)6mediator containing phosphate buffer (pH 6.5) anolyte and combined with a Pt wire cathode in phosphoric acid medium (pH 3.5). As a result, a two chamber microbial fuel cell (MFC) was formed, in which an activated Nafion membrane was used as a proton exchange membrane. The OsRP/G.oxydans/MWCNT-Au-Pt/CFE based bioanode was electrochemically examined in differently deoxygenated bioanode chambers and additionally the amounts of hybrid nanomaterial and OsRP were optimized. In terms of MFC characteristics, it was found that an anaerobic OsRP/G.oxydans/MWCNT-Au-Pt/CFE bioanode based MFC had a maximum power density of 32.1 mW m-2(at 90 mV), a maximum current density of 1032 mA m-2and a charge transfer efficiency (E%) value of 22.30 (open circuit potential 180 mV).
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| 3. |
- Aslan, Sema, et al.
(författare)
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Development of an Osmium Redox Polymer Mediated Bioanode and Examination of Its Performance in Gluconobacter oxydans Based Microbial Fuel Cell
- 2017
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Ingår i: Electroanalysis. - : Wiley. - 1040-0397. ; 29:6, s. 1651-1657
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Tidskriftsartikel (refereegranskat)abstract
- Gluconobacter oxydans (G. oxydans) cells together with an osmium redox polymer (ORP) [Osmium (2,2'-bipyridine)2(poly-vinylimidazole)10Cl]Cl were combined with a glassy carbon paste electrode (GCPE) to form a bioanode for a microbial fuel cell (MFC) based on G. oxydans. Although there are G.oxydans/ ORP combined bioanode in the literature, as far as it is known, this system is the first one where G.oxydans/ORP bioanode is combined with a cathode and a MFC is formed. After the optimization of experimental parameters, analytical characteristics of ORP/G. oxydans/GCPE bioanode were investigated. ORP/G. oxydans/GCPE showed two linear ranges for ethanol substrate as 1.0-30mM (R2=0.902) and 30-500mM (R2=0.997) and analytical range as 1.0-1000mM. Limit of detection (3.0s/m) and limit of quantification (10s/m) values were calculated as 1.29mM and 4.30mM respectively where the RSD value was 1.16% for n=5. Combining the developed bioanode in the presence of 5.0mM K3Fe(CN)6 mediator with a Pt wire cathode a double compartment MFC was obtained via a salt bridge. G. oxydans/GCPE bioanode based MFC had maximum power density of 0.133 μW cm-2 (at 33.5 mV), maximum current density as 8.73 μA cm-2 and OCP value of 156 mV. On the other hand, ORP/G. oxydans/GCPE based MFC showed maximum power density as 0.26 μW cm-2 (at 46.8 mV), maximum current density as 15.079 μA cm-2 and OCP value of 176 mV.
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| 4. |
- Bollella, Paolo, et al.
(författare)
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Highly sensitive, stable and selective hydrogen peroxide amperometric biosensors based on peroxidases from different sources wired by Os-polymer : A comparative study
- 2018
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Ingår i: Solid State Ionics. - : Elsevier BV. - 0167-2738. ; 314, s. 178-186
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Tidskriftsartikel (refereegranskat)abstract
- A comparison was made between two plant peroxidases, cationic horseradish peroxidase (HRP) and anionic tobacco peroxidase (TOP), combined with a highly cationic osmium polymer [Os(4,4'-dimethyl-2,2'-bipyridine)2poly(N-vinylimidazole)10Cl]+2/+ ([Os(dmp)PVI]+/2+) to develop highly sensitive, stable and selective hydrogen peroxide biosensors. The two different plant peroxidases were individually immobilized onto graphite rod (G) electrodes by a three steps drop-casting procedure consisting of the subsequent deposition of an aqueous solution of ([Os(dmp)PVI]+/2+), followed by a solution of poly(ethyleneglycol) diglycidyl ether (PEGDGE), used as a cross linking agent and finally an aliquot of a solution of cationic HRP or anionic TOP to make HRP/PEGDGE/[Os(dmp)PVI]+/2+/G and TOP/PEGDGE/[Os(dmp)PVI]+/2+/G based electrodes, respectively. Electrochemical experiments were carried out to investigate the influence of the surface charge of the enzyme and the charge of the polymer on the efficiency of the electron transfer (ET) between the enzyme and the wiring redox polymer and the efficiency for electrocatalytic reduction of H2O2. In the case of HRP a decrease in the ET rate was observed due to the repulsion between this enzyme and the polymer, both positively charged, whereas with TOP there was an enhanced ET rate due to the attraction between the anionic enzyme and the cationic polymer. The effects of enzyme loading and pH were investigated. Both peroxidase modified electrodes exhibited a wide dynamic response range (1-500μM H2O2) and a low detection limit (0.3μM H2O2). The TOP based electrode showed a higher sensitivity (470nAμM-1 cm-2) compared to that of the HRP based electrode (300nAμM-1 cm-2) and an improved long-term stability (decrease in 17.3% upon 30days compared with 50% for HRP). Both enzyme electrodes showed a response time of 3s. The HRP based sensor was more sensitive to the presence of phenolic compounds acting as alternative electron donors, whereas the TOP based sensor was virtually interference free. Both HRP and TOP based electrodes were successfully tested in contact lens cleaning samples and real "spiked" samples from different sources such as tap water, milk and dairy products.
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| 5. |
- Bunea, Ada-Ioana, et al.
(författare)
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Micropatterned Carbon-on-Quartz Electrode Chips for Photocurrent Generation from Thylakoid Membranes
- 2018
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Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 1:7, s. 3313-3322
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Tidskriftsartikel (refereegranskat)abstract
- Harvesting the energy generated by photosynthetic organisms through light-dependent reactions is a significant step toward a sustainable future energy supply. Thylakoid membranes are the site of photosynthesis, and thus particularly suited for developing photo-bioelectrochemical cells. Novel electrode materials and geometries could potentially improve the efficiency of energy harvesting using thylakoid membranes. For commercial applications, electrodes with large surface areas are needed. Photolithographic patterning of a photoresist, followed by pyrolysis, is a flexible and fast approach for the fabrication of carbon electrodes with tailored properties. In this work, electrode chips consisting of patterned carbon supported on quartz were designed and fabricated. The patterned electrode area is 1 cm2, and the measurement chamber footprint is 0.5 cm2, 1 order of magnitude larger than previously tested electrodes for thylakoid membrane immobilization. The use of a transparent substrate allows back-side illumination, protecting the bioelectrochemical system from the environment and vice versa. Two different mediators, monomeric ([Ru(NH3)6]3+) and polymeric ([Os(2,2′-bipyridine)2-poly(N-vinylimidazole)10Cl]+/2+), are used for evaluating photocurrent generation from thylakoid membranes with different electrode geometries. Current densities up to 71 μA cm–2 are measured upon illumination through the transparent electrode chip with solar simulated irradiance (1000 W m–2).
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| 6. |
- Darus, Libertus, et al.
(författare)
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Redox-polymers enable uninterrupted day/night photo-driven electricity generation in biophotovoltaic devices
- 2017
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 164:3, s. 3037-3040
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Tidskriftsartikel (refereegranskat)abstract
- Biophotovoltaic devices modified with immobilized polymeric osmium/azine redox-mediators exhibited a considerable electrical output enhancement (64/43-fold under light/dark conditions, respectively). More importantly, the systems exhibited uninterrupted current generation at same magnitude levels during day/night cycles, paving the way toward solar energy conversion bio-panels that will not require energy storage peripherals.
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| 7. |
- Falk, Magnus, et al.
(författare)
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Self-powered wireless carbohydrate/oxygen sensitive biodevice based on radio signal transmission
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 9:10, s. e109104/1-e109104/9
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Tidskriftsartikel (refereegranskat)abstract
- Here for the first time, we detail self-contained (wireless and self-powered) biodevices with wireless signal transmission. Specifically, we demonstrate the operation of self-sustained carbohydrate and oxygen sensitive biodevices, consisting of a wireless electronic unit, radio transmitter and sep. sensing bioelectrodes, supplied with elec. energy from a combined multi-enzyme fuel cell generating sufficient current at required voltage to power the electronics. A carbohydrate/oxygen enzymic fuel cell was assembled by comparing the performance of a range of different bioelectrodes followed by selection of the most suitable, stable combination. Carbohydrates (viz. lactose for the demonstration) and oxygen were also chosen as bioanalytes, being important biomarkers, to demonstrate the operation of the self-contained biosensing device, employing enzyme-modified bioelectrodes to enable the actual sensing. A wireless electronic unit, consisting of a micropotentiostat, an energy harvesting module (voltage amplifier together with a capacitor) and a radio microchip, were designed to enable the biofuel cell to be used as a power supply for managing the sensing devices and for wireless data transmission. The electronic system used required current and voltages greater than 44 μA and 0.57 V, resp. to operate; which the biofuel cell was capable of providing, when placed in a carbohydrate and oxygen contg. buffer. In addn., a USB based receiver and computer software were employed for proof-of concept tests of the developed biodevices. Operation of bench-top prototypes was demonstrated in buffers contg. different concns. of the analytes, showcasing that the variation in response of both carbohydrate and oxygen biosensors could be monitored wirelessly in real-time as analyte concns. in buffers were changed, using only an enzymic fuel cell as a power supply.
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| 8. |
- Figueiredo, Carina, et al.
(författare)
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Effect of Protection Polymer Coatings on the Performance of an Amperometric Galactose Biosensor in Human Plasma
- 2024
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Ingår i: Biosensors. - 2079-6374. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- Galactose monitoring in individuals allows the prevention of harsh health conditions related to hereditary metabolic diseases like galactosemia. Current methods of galactose detection need development to obtain cheaper, more reliable, and more specific sensors. Enzyme-containing amperometric sensors based on galactose oxidase activity are a promising approach, which can be enhanced by means of their inclusion in a redox polymer coating. This strategy simultaneously allows the immobilization of the biocatalyst to the electroactive surface and hosts the electron shuttling units. An additional deposition of capping polymers prevents external interferences like ascorbic or uric acid as well as biofouling when measuring in physiological fuels. This work studies the protection effect of poly(2-methacryloyloxyethyl phosphorylcholine-co-glycidyl methacrylate (MPC) and polyvinylimidazole-polysulfostyrene (P(VI-SS)) when incorporated in the biosensor design for the detection of galactose in human plasma.
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| 9. |
- Gonaus, Christoph, et al.
(författare)
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Analysis of Agaricus meleagris pyranose dehydrogenase N-glycosylation sites and performance of partially non-glycosylated enzymes
- 2017
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Ingår i: Enzyme and Microbial Technology. - : Elsevier BV. - 0141-0229. ; 99, s. 57-66
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Tidskriftsartikel (refereegranskat)abstract
- Pyranose Dehydrogenase 1 from the basidiomycete Agaricus meleagris (AmPDH1) is an oxidoreductase capable of oxidizing a broad variety of sugars. Due to this and its ability of dioxidation of substrates and no side production of hydrogen peroxide, it is studied for use in enzymatic bio-fuel cells. In-vitro deglycosylated AmPDH1 as well as knock-out mutants of the N-glycosylation sites N75 and N175, near the active site entrance, were previously shown to improve achievable current densities of graphite electrodes modified with AmPDH1 and an osmium redox polymer acting as a redox mediator, up to 10-fold. For a better understanding of the role of N-glycosylation of AmPDH1, a systematic set of N-glycosylation site mutants was investigated in this work, regarding expression efficiency, enzyme activity and stability. Furthermore, the site specific extend of N-glycosylation was compared between native and recombinant wild type AmPDH1. Knocking out the site N252 prevented the attachment of significantly extended N-glycan structures as detected on polyacrylamide gel electrophoresis, but did not significantly alter enzyme performance on modified electrodes. This suggests that not the molecule size but other factors like accessibility of the active site improved performance of deglycosylated AmPDH1/osmium redox polymer modified electrodes. A fourth N-glycosylation site of AmPDH1 could be confirmed by mass spectrometry at N319, which appeared to be conserved in related fungal pyranose dehydrogenases but not in other members of the glucose-methanol-choline oxidoreductase structural family. This site was shown to be the only one that is essential for functional recombinant expression of the enzyme.
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| 10. |
- Hamidi, Hassan, et al.
(författare)
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Photocurrent Generation from Thylakoid Membranes on Osmium-Redox-Polymer-Modified Electrodes.
- 2015
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Ingår i: ChemSusChem. - : Wiley. - 1864-564X .- 1864-5631. ; 8:6, s. 990-993
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Tidskriftsartikel (refereegranskat)abstract
- Thylakoid membranes (TMs) are uniquely suited for photosynthesis owing to their distinctive structure and composition. Substantial efforts have been directed towards use of isolated photosynthetic reaction centers (PRCs) for solar energy harvesting, however, few studies investigate the communication between whole TMs and electrode surfaces, due to their complex structure. Here we report on a promising approach to generate photosynthesis-derived bioelectricity upon illumination of TMs wired with an osmium-redox-polymer modified graphite electrode, and generate a photocurrent density of 42.4 μA cm(-2) .
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