| 1. |
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| 2. |
- Clot, Sylvain, et al.
(författare)
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Laccase cathode approaches to physiological conditions by local pH acidification
- 2012
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Ingår i: Electrochemistry communications. - : Elsevier. - 1388-2481 .- 1873-1902. ; 18, s. 37-40
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Tidskriftsartikel (refereegranskat)abstract
- A new conceptual approach to improve the performance of a laccase-based cathode at neutral pH is presented. The working pH of Trametes hirsuta laccase, typically acidic, can be achieved by oxidn. of biol. compds. such as glucose catalyzed by a second enzyme immobilized in the vicinity of the laccase electrode.
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| 3. |
- Cruz, Raquel, et al.
(författare)
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Novel genes and sex differences in COVID-19 severity
- 2022
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Ingår i: Human Molecular Genetics. - : Oxford University Press. - 0964-6906 .- 1460-2083. ; 31:22, s. 3789-3806
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Tidskriftsartikel (refereegranskat)abstract
- Here, we describe the results of a genome-wide study conducted in 11 939 coronavirus disease 2019 (COVID-19) positive cases with an extensive clinical information that were recruited from 34 hospitals across Spain (SCOURGE consortium). In sex-disaggregated genome-wide association studies for COVID-19 hospitalization, genome-wide significance (P < 5 × 10−8) was crossed for variants in 3p21.31 and 21q22.11 loci only among males (P = 1.3 × 10−22 and P = 8.1 × 10−12, respectively), and for variants in 9q21.32 near TLE1 only among females (P = 4.4 × 10−8). In a second phase, results were combined with an independent Spanish cohort (1598 COVID-19 cases and 1068 population controls), revealing in the overall analysis two novel risk loci in 9p13.3 and 19q13.12, with fine-mapping prioritized variants functionally associated with AQP3 (P = 2.7 × 10−8) and ARHGAP33 (P = 1.3 × 10−8), respectively. The meta-analysis of both phases with four European studies stratified by sex from the Host Genetics Initiative (HGI) confirmed the association of the 3p21.31 and 21q22.11 loci predominantly in males and replicated a recently reported variant in 11p13 (ELF5, P = 4.1 × 10−8). Six of the COVID-19 HGI discovered loci were replicated and an HGI-based genetic risk score predicted the severity strata in SCOURGE. We also found more SNP-heritability and larger heritability differences by age (<60 or ≥60 years) among males than among females. Parallel genome-wide screening of inbreeding depression in SCOURGE also showed an effect of homozygosity in COVID-19 hospitalization and severity and this effect was stronger among older males. In summary, new candidate genes for COVID-19 severity and evidence supporting genetic disparities among sexes are provided.
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| 4. |
- Di Bari, Chiara, et al.
(författare)
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Fabrication of high surface area graphene electrodes with high performance towards enzymatic oxygen reduction
- 2016
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Ingår i: Electrochimica Acta. - : Elsevier. - 0013-4686 .- 1873-3859. ; 191, s. 500-509
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Tidskriftsartikel (refereegranskat)abstract
- High surface area graphene electrodes were prepd. by simultaneous electrodeposition and electroredn. of graphene oxide. The electrodeposition process was optimized in terms of pH and cond. of the soln. and the obtained graphene electrodes were characterized by XPS, FTIR spectroscopy, SEM and electrochem. methods (cyclic voltammetry and impedance spectroscopy). Electrodeposited electrodes were further functionalized to carry out covalent immobilization of two O-reducing multicopper oxidases: laccase and bilirubin oxidase. The enzymic electrodes were tested as direct electron transfer based biocathodes and catalytic currents ≤1 mA/cm2 were obtained. Finally, the mechanism of the enzymic O redn. reaction was studied for both enzymes calcg. the Tafel slopes and transfer coeffs.
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| 5. |
- Di Bari, Chiara, et al.
(författare)
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Halides inhibition of multicopper oxidases studied by FTIR spectroelectrochemistry using azide as an active infrared probe
- 2017
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Ingår i: Journal of Biological Inorganic Chemistry. - : Springer. - 0949-8257 .- 1432-1327. ; 22:8, s. 1179-1186
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Tidskriftsartikel (refereegranskat)abstract
- An IR spectroelectrochem. study of Trametes hirsuta laccase and Magnaporthe oryzae bilirubin oxidase has been performed using azide, an inhibitor of multicopper oxidases, as an active IR probe incorporated into the T2/T3 copper cluster of the enzymes. The redox potential-controlled measurements indicate that N3- stretching IR bands of azide ion bound to the T2/T3 cluster are only detected for the oxidized enzymes, confirming that azide only binds to Cu2+. Moreover, the process of binding/dissocn. of azide ion is shown to be reversible. The interaction of halide anions, which also inhibit multicopper oxidases, with the active site of the enzymes was studied by measuring the changes in the azide FTIR bands. Enzymes inhibited by azide respond differently upon addn. of fluoride or chloride ions to the sample soln. inhibited by azide. Fluoride ions compete with azide for binding at one of the T2/T3 Cu ions, whereas competition from chloride ions is much less evident.
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| 6. |
- Di Bari, Chiara, et al.
(författare)
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Laccase-modified gold nanorods for electrocatalytic reduction of oxygen
- 2016
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Ingår i: Bioelectrochemistry. - : Elsevier. - 1567-5394 .- 1878-562X. ; 107, s. 30-36
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Tidskriftsartikel (refereegranskat)abstract
- The multicopper oxidase Trametes hirsuta laccase (ThLc) served as a bioelectrocatalyst on nanostructured cathodes. Nanostructuring was provided by gold nanorods (AuNRs), which were characterized and covalently attached to electrodes made of low-d. graphite. The nanostructured electrode was the scaffold for covalent and oriented attachment of ThLc. The bioelectrocatalytic currents measured for oxygen redn. were as high as 0.5 mA/cm2 and 0.7 mA/cm2, which were recorded under direct and mediated electron transfer regimes, resp. The exptl. data were fitted to math. models showing that when the O2 is bioelectroreduced at high rotation speed of the electrode the heterogeneous electron transfer step is the rate-liming stage. The electrochem. measurement hints a wider population of non-optimally wired laccases than previously reported for 5-8 nm size Au nanoparticle-modified electrode, which could be due to a larger size of the AuNRs when compared to the laccases as well as their different crystal facets.
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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. |
- Gonzalez-Arribas, Elena, et al.
(författare)
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Transparent, mediator- and membrane-free enzymatic fuel cell based on nanostructured chemically modified indium tin oxide electrodes
- 2017
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Ingår i: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 97, s. 46-52
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Tidskriftsartikel (refereegranskat)abstract
- We detail a mediator- and membrane-free enzymatic glucose/oxygen biofuel cell based on transparent and nanostructured conducting supports. Chemically modified indium tin oxide nanoparticle modified electrodes were used to substantially increase the active surface area without significantly compromising transparency. Two different procedures for surface nanostructuring were employed, viz. spray-coating and drop-coating. The spray-coated biodevice showed superior characteristics as compared to the drop-coated enzymatic fuel cell, as a result of the higher nanostructured surface area as confirmed by electrochemical characterisation, as well as scanning electron and atomic force microscopy. Subsequent chemical modification with silanes, followed by the immobilisation of either cellobiose dehydrogenase from Corynascus thermophiles or bilirubin oxidase from Myrothecium verrucaria, were performed to obtain the bioanodes and biocathodes, respectively. The optimised biodevice exhibited an OCV of 0.67 V and power output of up to 1.4 mu W/cm(2) at an operating voltage of 0.35 V. This is considered a significant step forward in the field of glucose/oxygen membrane- and mediator-free, transparent enzymatic fuel cells.
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| 10. |
- Gutierrez-Sanchez, Cristina, et al.
(författare)
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Gold nanoparticles as electronic bridges for laccase-based biocathodes
- 2012
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 134:41, s. 17212-17220
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Tidskriftsartikel (refereegranskat)abstract
- Direct electron transfer (DET) reactions between redox enzymes and electrodes can be maximized by oriented immobilization of the enzyme mols. onto an electroactive surface modified with functionalized Au nanoparticles (AuNPs). Here, the authors present such strategy for obtaining a DET-based laccase (Lc) cathode for O2 electroredn. at low overpotentials. The stable nanostructured enzymic electrode is based on the step-by-step covalent attachment of AuNPs and Lc mols. to porous graphite electrodes using the diazonium salt redn. strategy. Oriented immobilization of the enzyme mols. on adequately functionalized AuNPs allows establishing very fast DET with the electrode via their Cu T1 site. The measured electrocatalytic waves of O2 redn. can be deconvoluted into two contributions. The one at lower overpotentials corresponds to immobilized Lc mols. that are efficiently wired by the AuNPs with a heterogeneous electron transfer rate const. k0 » 400 s-1.
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