| 1. |
- Pankratov, Dmitry, et al.
(författare)
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Impact of surface modification with gold nanoparticles on the bioelectrocatalytic parameters of immobilized bilirubin oxidase
- 2014
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Ingår i: Acta Naturae. - : Park Media Ltd. - 2075-8251. ; 6:1, s. 102-106
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Tidskriftsartikel (refereegranskat)abstract
- We unveil experimental evidence that put into question the widely held notion concerning the impact of nanoparticles on the bioelectrocatalytic parameters of enzymatic electrodes. Comparative studies of the bioelectrocatalytic properties of fungal bilirubin oxidase from Myrothecium verrucaria adsorbed on gold electrodes, modified with gold nanoparticles of different diameters, clearly indicate that neither the direct electron transfer rate (standard heterogeneous electron transfer rate constants were calculated to be 31±9 s-1) nor the biocatalytic activity of the adsorbed enzyme (bioelectrocatalytic constants were calculated to be 34±11 s-1) depends on the size of the nanoparticles, which had diameters close to or larger than those of the enzyme molecules.
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| 2. |
- Pankratov, Dmitry, et al.
(författare)
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Scalable, high performance, enzymatic cathodes based on nanoimprint lithography
- 2015
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Ingår i: Beilstein Journal of Nanotechnology. - : Beilstein Institut. - 2190-4286. ; 6, s. 1377-1384
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Tidskriftsartikel (refereegranskat)abstract
- Here we detail high performance, enzymatic electrodes for oxygen bio-electroreduction, which can be easily and reproducibly fabricated with industry-scale throughput. Planar and nanostructured electrodes were built on biocompatible, flexible polymer sheets, while nanoimprint lithography was used for electrode nanostructuring. To the best of our knowledge, this is one of the first reports concerning the usage of nanoimprint lithography for amperometric bioelectronic devices. The enzyme (Myrothecium verrucaria bilirubin oxidase) was immobilised on planar (control) and artificially nanostructured, gold electrodes by direct physical adsorption. The detailed electrochemical investigation of bioelectrodes was performed and the following parameters were obtained: open circuit voltage of approximately 0.75 V, and maximum bio-electrocatalytic current densities of 18 mu A/cm(2) and 58 mu A/cm(2) in air-saturated buffers versus 48 mu A/cm(2) and 186 mu A/cm(2) in oxygen-saturated buffers for planar and nanostructured electrodes, respectively. The half-deactivation times of planar and nanostructured biocathodes were measured to be 2 h and 14 h, respectively. The comparison of standard heterogeneous and bio-electrocatalytic rate constants showed that the improved bio-electrocatalytic performance of the nanostructured biocathodes compared to planar biodevices is due to the increased surface area of the nanostructured electrodes, whereas their improved operational stability is attributed to stabilisation of the enzyme inside nanocavities.
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| 3. |
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| 4. |
- Pankratov, Dmitry, et al.
(författare)
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The influence of nanoparticles on enzymatic bioelectrocatalysis
- 2014
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 4:72, s. 38164-38168
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Tidskriftsartikel (refereegranskat)abstract
- In nearly all papers concerning enzyme–nanoparticle based bioelectronic devices, it is stated that the presence of nanoparticles on electrode surfaces per se enhances bioelectrocatalysis, although the reasons for that enhancement are often unclear. Here, we report detailed experimental evidence that neither an overpotential of bioelectrocatalysis, nor direct electron transfer and bioelectrocatalytic reaction rates for an adsorbed enzyme depend on the size of nanoparticles within the range of 20–80 nm, i.e. for nanoparticles that are considerably larger than the enzyme molecules.
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| 5. |
- Pankratov, Dmitry, et al.
(författare)
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The influence of nanoparticles on enzymatic bioelectrocatalysis
- 2014
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:72, s. 38164-38168
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Tidskriftsartikel (refereegranskat)abstract
- In nearly all papers concerning enzyme-nanoparticle based bio-electronic devices, it is stated that the presence of nanoparticles on electrode surfaces per se enhances bioelectrocatalysis, although the reasons for that enhancement are often unclear. Here, we report detailed experimental evidence that neither an overpotential of bioelectrocatalysis, nor direct electron transfer and bioelectrocatalytic reaction rates for an adsorbed enzyme depend on the size of nanoparticles within the range of 20-80 nm, i.e. for nanoparticles that are considerably larger than the enzyme molecules.
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| 6. |
- Pankratov, Dmitry, et al.
(författare)
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Transparent and flexible, nanostructured and mediatorless glucose/oxygen enzymatic fuel cells
- 2015
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 1873-2755 .- 0378-7753. ; 294, s. 501-506
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Tidskriftsartikel (refereegranskat)abstract
- Here we detail transparent, flexible, nanostructured, membrane-less and mediator-free glucose/oxygen enzymatic fuel cells, which can be reproducibly fabricated with industrial scale throughput. The electrodes were built on a biocompatible flexible polymer, while nanoimprint lithography was used for their nanostructuring. The electrodes were covered with gold, their surfaces were visualised using scanning electron and atomic force microscopies, and they were also studied spectrophotometrically and electrochemically. The enzymatic fuel cells were fabricated following our previous reports on membrane-less and mediator-free biodevices in which cellobiose dehydrogenase and bilirubin oxidase were used as anodic and cathodic biocatalysts, respectively. The following average characteristics of transparent and flexible biodevices operating in glucose and chloride containing neutral buffers were registered: 0.63 V open-circuit voltage, and 0.6 mu W cm(-2) maximal power density at a cell voltage of 0.35 V. A transparent and flexible enzymatic fuel cell could still deliver at least 0.5 mu W cm(-2) after 12 h of continuous operation. Thus, such biodevices can potentially be used as self-powered biosensors or electric power sources for smart electronic contact lenses. (C) 2015 Elsevier B.V. All rights reserved.
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| 7. |
- Blum, Zoltan, et al.
(författare)
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Powering electronic contact lenses : current achievements, challenges, and perspectives
- 2014
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Ingår i: Expert Review of Ophthalmology. - : Expert Reviews. - 1746-9902 .- 1746-9899. ; 9:4, s. 269-273
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Tidskriftsartikel (refereegranskat)abstract
- The recent media hoopla regarding ‘smart’, ‘bionic’, or more appropriately, electronically augmented contact lenses is analyzed in terms of real achievements coupled to the critically important issue of power management. Not depending on the availability, currently or in the near future, of to-the-purpose discrete or integrated electronic devices, power management, including delivery/supply and temporal sustainability, will be an outstanding issue if present-day technology should remain the only option. Radically different approaches have been taken to deliver electric power to electronically augmented contact lenses, that is, ranging from quite simplistic wire-based delivery assemblies, grossly inappropriate for end users, to various elaborate wireless designs drawing on over-the-air power delivery, as well as solar and electrochemical cells. Nonetheless, given the complex restrictions offered by a contact lens, conventional, even state-of-the-art, power management technology is at an impasse, and to ensure a bright future for smart lenses, radical technological measures need to be taken. Bridging the conceptual gap between fuel cells and supercapacitors, an ingenious novel approach to on-lens power management is presented: a charge-storing fuel cell, or alternatively, a self-charging capacitor, that is, a hybrid electric power device.
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| 8. |
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| 9. |
- Falk, Magnus, et al.
(författare)
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Miniature direct electron transfer based enzymatic fuel cell operating in human sweat and saliva
- 2014
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Ingår i: Fuel Cells. - : John Wiley & Sons. - 1615-6846 .- 1615-6854. ; 14:6, s. 1050-1056
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Tidskriftsartikel (refereegranskat)abstract
- We present data on operation of a miniature membrane-less, direct electron transfer based enzymatic fuel cell in human sweat and saliva. The enzymatic fuel cell was fabricated following our previous reports on miniature biofuel cells, utilizing gold nanoparticle modified gold microwires with immobilized cellobiose dehydrogenase and bilirubin oxidase. The following average characteristics of miniature glucose/oxygen biodevices operating in human sweat and saliva, respectively, were registered: 580 and 560 mV open-circuit voltage, 0.26 and 0.1 μW cm–2 power density at a cell voltage of 0.5 V, with up to ten times higher power output at 0.2 V. When saliva collected after meal ingestion was used, roughly a two-fold increase in power output was obtained, with a further two-fold increase by addition of 500 μM glucose. Likewise, the power generated in sweat at 0.5 V increased two-fold by addition of 500 μM glucose.
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| 10. |
- Gonzalez-Arribas, Elena, et al.
(författare)
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Transparent and Capacitive Bioanode Based on Specifically Engineered Glucose Oxidase
- 2016
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Ingår i: Electroanalysis. - : John Wiley & Sons. - 1040-0397 .- 1521-4109. ; 28:6, s. 1290-1297
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Tidskriftsartikel (refereegranskat)abstract
- Here the authors detail an optimized transparent capacitive glucose oxidizing bioanode, capable of supplying current densities of 10 μA cm-2 at applied potentials of 0.1 V-0.2 V vs. SCE, when continuously performing in a simple phosphate buffer, pH 7.4 and artificial human tears, both with a glucose concn. of 0.05 mM only. When operating in pulse mode, the bioanode was able to deliver current densities ≤21 μA cm-2 at the beginning of the pulse with 571 μC cm-2 total charges stored. The biogenic part of the enzymic device was a recombinant glucose oxidase mutant from Penicillium amagasakiense with high catalytic efficiency towards glucose, up to 14.5x104 M-1 s-1. The nonbiogenic part of the anodic system was based on a poly(3,4-ethylenedioxythiophene)-graphene nanocomposite, as a highly capacitive component with a capacitance d. in the 1 mF cm-2 range, multi-walled carbon nanotubes, as an addnl. nanostructuring element, and a conductive org. complex, as an electron shuttle between the redox enzyme and the electrode surface. The bioanode could potentially serve as a prototype of a double-function enzymic anode for hybrid elec. power biodevices, energizing smart contact lenses.
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