Mikael Bergelin - Academia.edu (original) (raw)

Papers by Mikael Bergelin

Measurement Setup to Study the Electrode Potentials Separately in a Printed Biofuel Cell. [ECS Me... more Measurement Setup to Study the Electrode Potentials Separately in a Printed Biofuel Cell. [ECS Meeting Abstracts 1001, 420 (2010)]. Saara Tuurala, Maria H. Smolander, Matti Valkiainen, Anu Vaari, Ville-Mikko Ojala, Mikael Bergelin.

Oxidation of Metals

The present study investigates the early stages of the oxide layer degradation process of Sanicro... more The present study investigates the early stages of the oxide layer degradation process of Sanicro 28 (Fe31Cr27Ni) stainless steel when exposed to KCl at 450 and 535 °C. A novel combinatory technique was developed and utilized, where CA was employed as a qualitative method to follow the varying stages of the onset of the corrosion reaction. XPS was then used to identify the elemental distribution and depth profile within the oxide layer at each identified reaction stage, and the resulting change in surface morphology and the progress of the corrosion front was studied by SEM-EDXA. Additionally, the main mechanism behind the spreading of the reaction front was identified using a novel test approach. The corrosion reaction could be separated into several overlapping stages, with the process being initiated by the alternation of the oxide layer resulting in the loss of passivity, the formation of chromate within the oxide layer and finally the oxidation of the chromium and iron from und...

Sensing and Bio-Sensing Research, 2015

In this work, biobatteries assembled using roll-to-roll screen printed enzymatic electrodes were ... more In this work, biobatteries assembled using roll-to-roll screen printed enzymatic electrodes were characterised in terms of their electrical performance and storage stability. The enzymes and mediators used on the anode and cathode were glucose oxidase with ferrocenemethanol and laccase with ABTS, respectively. This study shows that besides rheological properties of enzyme inks used for the printing of the biobattery electrodes also adhesion of these electrodes to the printing substrate can be adjusted by varying the amount and composition of the binder in the ink. Another important observation is that the mediator has a strong impact on both the performance and the stability of the anode electrode. Consequently, electrochemical performance of biobatteries can be enhanced by adding fresh mediator into the battery during activation or by some other method preserving the activity of the mediator.

Solid State Phenomena, 2015

ABSTRACT

Journal of Applied Electrochemistry, 2014

ABSTRACT Production of printable enzymatic power sources was scaled up from laboratory to roll-to... more ABSTRACT Production of printable enzymatic power sources was scaled up from laboratory to roll-to-roll (R2R) pilot production. The anode and cathode enzymes were glucose oxidase (GOx) and laccase, respectively. The best laboratory-scale cells had a maximum power and energy density of 1.4 ± 0.1 µW cm−2 and 5.5 ± 0.2 µWh cm−2, respectively. These values are 5 and 28 times higher compared to our previously published values. The R2R-produced cells had a maximum power and energy density of 0.40 ± 0.03 µW cm−2 and 0.6 ± 0.1 µWh cm−2, respectively. This is 11 % of the best laboratory manufactured cells. It is suspected that the decrease in electrochemical performance originates from the lower mediator amount and higher drying temperature than that of the laboratory produced cells. However, the trials conducted in this work showed that printed enzymatic active layers can be fabricated and dried with a rotary screen-printing machine in R2R process. Hence, fully printed GOx//laccase power sources could be produced from R2R on a large scale for printed electronics applications.

Synthetic Metals, 2010

Poly(3,4-ethylenedioxythiophene) (PEDOT) films, with Cl−, NO3−, poly(styrene sulfonate) (PSS−) or... more Poly(3,4-ethylenedioxythiophene) (PEDOT) films, with Cl−, NO3−, poly(styrene sulfonate) (PSS−) or carbon nanotubes (CNTs) as counter ions, were electrochemically deposited onto indium tin oxide (ITO) glass from aqueous electrolyte. PEDOT film, with tetrafluoroborate anions (BF4−) as counter ions, was also electrochemically deposited on ITO glass from a propylene carbonate-based electrolyte. The effect of counter ions on the morphology of PEDOT films

Journal of Power Sources, 2003

Catalyst materials in form of inks, as half-MEAs and inside a polymer electrolyte membrane unit c... more Catalyst materials in form of inks, as half-MEAs and inside a polymer electrolyte membrane unit cell were characterized by cyclic voltammetry. Laboratory made Pt inks were modified with Ru, Os and Ru þ Ir and the methanol oxidation activity of the created surfaces was tested. A novel electrode, which enables the study of the oxygen reduction reaction on the cathode was introduced. With the measuring device it was possible to vary the oxygen content on the ink side and the proton activity of the electrolyte on the membrane side of a half-MEA. Catalyst layers based on Pt, Pt-Ru and Pt-Co inside a PEM-unit cell were also characterized in situ by cyclic voltammetry. The active surface areas were found to be linearly dependent on the Pt mass density in the catalyst layers. Approximately 30% of the Pt loading in the MEAs were electroactive. #

Journal of Power Sources, 2011

ABSTRACT Journal of Power Sources Vol.196 Nr.11, 4957-4964

Journal of Electroanalytical Chemistry, 2002

The behaviour of Os submonolayers on polycrystalline Pt was investigated by means of a flow cell ... more The behaviour of Os submonolayers on polycrystalline Pt was investigated by means of a flow cell of impinging jet type. Os was electrodeposited onto the electrode for various periods of time. From the loss in the hydrogen region charge it was possible to estimate the Os surface coverage. The activity of Os towards hydrogen adsorption was also studied by depositing the metal onto an Au electrode. An estimation of 40% hydrogen coverage for Os was made, which was taken into consideration in the determination of the Os coverage. Another method for estimating the surface coverage was also considered where the oxidation charge of OsO 4 was taken as a measure of the amount of Os present on the surface. It was also found that the deposition potential influences the voltammetry in the hydrogen region. A potential dependent preferential deposition onto Pt [110] and Pt[100] surface sites was observed. #

Enzyme and Microbial Technology, 2008

Laccases belong to the family of blue multicopper oxidases, which catalyze the four-electron redu... more Laccases belong to the family of blue multicopper oxidases, which catalyze the four-electron reduction of dioxygen to water concomitantly through the oxidation of phenolic and other aromatic compounds. They are potential enzymes in many applications including biofuel cells to produce electricity through chemical reactions. We have tested here the incorporation of a high redox potential laccase from Trametes hirsuta in different types of conducting inks to produce dry printed enzyme electrode layers. ABTS was used as the redox mediator to shuttle the electrons between the surface of the cathodic electrode and the enzyme active sites. Our results demonstrate that the dry printed layers maintained their enzymatic activity even after several months. Furthermore, fuel cell prototypes could be constructed utilising an optimized printed laccase-ABTS layer as the cathode, and printed Zn layer as the anode. Under humidity controlled conditions, a cell voltage between 0.8 and 0.6 V could be maintained for several days under a 2.2 k load. In addition, a corresponding stand-alone cell could be constructed where the cell voltage was maintained for 15 h under a load. These results offer a good starting point for further development of mass-producible, completely enzymatic printed biofuel cells.

Electrochimica Acta, 2012

An O 2 -consuming cathode for biofuel cell applications consisting of Trametes hirsuta laccase (T... more An O 2 -consuming cathode for biofuel cell applications consisting of Trametes hirsuta laccase (ThL) immobilized in an electropolymerized fine-tuned poly(3,4-ethylenedioxythiophene) (PEDOT) bilayer structure as the catalyst was studied. A NO 3 − -doped PEDOT layer with a relatively porous structure was used as the immobilization matrix on which the enzyme was added by solution casting. A capping layer of polystyrene sulphonate, PSS − -doped PEDOT was then electrodeposited on top of the first PEDOT layer in order to entrap the ThL between the layers. The PEDOT-NO 3 − /ThL/PEDOT-PSS − enzyme electrode is reported to be able to promote direct electron transfer (DET) between ThL and the current collector and it catalyzes the reduction of O 2 into water. The applicability of the PEDOT-NO 3 − /ThL/PEDOT-PSS − enzyme electrode structure on ITO glass with a geometrical surface area of 1 cm 2 as the electrode material was studied. The influence of different enzyme electrode fabrication parameters, such as the dopant ion used during electropolymerization, different combinations of PEDOT films, the thickness of both PEDOT layers and ThL loading on the enzyme electrode performance were investigated by chronoamperometric and cyclic voltammetric measurements. The optimum working pH for the enzyme electrode was found to be in the pH range 3.0-3.5. No enhanced cell performance was recorded when 2,2 -azinobis(3ethylbenzothiazoline-6-sulfonate) (ABTS) was used as mediator compared to DET in the PEDOT bilayer structure.

Electrochimica Acta, 1998

An impinging jet electrochemical¯ow cell developed for use with bead type electrodes was successf... more An impinging jet electrochemical¯ow cell developed for use with bead type electrodes was successfully employed in a surface structure sensitive study involving the processes of CO adsorption and oxidation on Pt(111) in 1.0 mol dm À3 H 2 SO 4 and HClO 4 . The¯ow cell enabled straightforward CO coverage control by means of varying the dosing time. Anion and hydrogen displacement charge curves with high potential resolution were obtained by means of CO adsorption and an electrolyte dependent ®ne structure was found. During the dosing of the electrolyte dissolved CO in the potential range 700±800 mV (vs. RHE) a slow delayed oxidation of adsorbed CO was noted and interpreted as being due to adsorption competition between CO and an oxygen containing species. A novel anion±anion displacement method was developed in which adsorbed bisulfate was replaced by perchlorate or water. The negative current transient obtained indicated desorption of bisulfate. #

Electrochimica Acta, 2012

ABSTRACT Printed supercapacitors were prepared to be applied as a part of a hybrid power source i... more ABSTRACT Printed supercapacitors were prepared to be applied as a part of a hybrid power source in printed electronics applications. The use of non-toxic materials was preferred. The supercapacitor structure consisting of current collectors and activated carbon electrodes was applied on paperboard substrate using silver, graphite and activated carbon inks. Aqueous electrolytes with NaCl salt limit the maximum potential to about 1.2 V but are environmentally friendly and provide low equivalent series resistance (ESR).The capacitance values of our printed supercapacitors were typically 0.1–0.5 F. With 2 cm2 geometrical active area the ESR was below 1 Ω which is acceptable for 50 mA current output. The efficiency with 50 mA charge and discharge current was typically about 90% and with 10 mA about 95%.

Measurement Setup to Study the Electrode Potentials Separately in a Printed Biofuel Cell. [ECS Me... more Measurement Setup to Study the Electrode Potentials Separately in a Printed Biofuel Cell. [ECS Meeting Abstracts 1001, 420 (2010)]. Saara Tuurala, Maria H. Smolander, Matti Valkiainen, Anu Vaari, Ville-Mikko Ojala, Mikael Bergelin.

Biosensors and Bioelectronics, 2012

We report on the fabrication and characterisation of a gold-nanoparticle (AuNP)-based mediatorles... more We report on the fabrication and characterisation of a gold-nanoparticle (AuNP)-based mediatorless sugar/oxygen biofuel cell (BFC) operating in neutral sugar-containing buffers and human physiological fluids, such as blood and plasma. First, Corynascus thermophilus cellobiose dehydrogenase (CtCDH) and Myrothecium verrucaria bilirubin oxidase (MvBOx), used as anodic and cathodic bioelements, respectively, were immobilised on gold electrodes modified with 20 nm AuNPs. Detailed characterisation and optimisation of a new CDH/AuNP-based bioanode were performed and the following fundamental parameters were obtained: (i) the redox potential of the haem-containing centre of the enzyme was measured to be 75 mV vs. NHE, (ii) the surface coverage of CtCDH was found to be 0.65 pmol cm −2 corresponding to a sub-monolayer coverage of the thiol-modified AuNPs by the enzyme, (iii) a turnover number for CtCDH immobilised on thiol-modified AuNPs was calculated to be ca. 0.5 s −1 , and (iv) the maximal current densities as high as 40 A cm −2 were registered in sugar-containing neutral buffers. Second, both biomodified electrodes, namely the CtCDH/AuNP-based bioanode and the MvBOx/AuNP-based biocathode, were combined into a functional BFC and the designed biodevices were carefully investigated. The following characteristics of the mediator-, separator-and membrane-less, miniature BFC were obtained: in phosphate buffer; an open-circuit voltage of 0.68 V, a maximum power density of 15 W cm −2 at a cell voltage of 0.52 V and in human blood; an open-circuit voltage of 0.65 V, a maximum power density of 3 W cm −2 at a cell voltage of 0.45 V, respectively. The estimated half-lives of the biodevices were found to be >12, <8, and <2 h in a sugar-containing buffer, human plasma, and blood, respectively. The basic characteristics of mediatorless sugar/oxygen BFCs were significantly improved compared with previously designed biodevices, because of the usage of three-dimensional AuNP-modified electrodes. (S. Shleev). URL: http://www.mah.se/Shleev (S. Shleev). 1 X. Wang and M. Falk equally contributed to the present work.

Advances in Science and Technology, 2010

ABSTRACT Advances in Science and Technology Vol.72, 331-336 Low cost printable power sources are ... more ABSTRACT Advances in Science and Technology Vol.72, 331-336 Low cost printable power sources are needed e.g. in sensors and RFID applications. As manufacturing method printing techniques are preferred in order to keep the costs low. The materials should also be easily disposable. Enzymatic bio-fuel cells are an alternative for printable primary batteries. Since one drawback of bio-fuel cells is their low power, we have developed supercapacitors that can be combined with enzymatic bio-fuel cells to provide the power peaks necessary in the applications. The materials for the supercapacitors have been chosen to be compatible with the fuel cell and with printing methods, e.g. the activated carbon powder in the electrodes was bound with chitosan. As printing substrates we have used paperboards. The current collectors have been made of graphite and metal inks. Since the voltage requirement is limited to approximately 1 V, aqueous electrolytes have been used. Printed supercapacitors of various sizes have been prepared. The geometrical electrode areas have been between 0.5 and 2 cm2. The maximum feasible output current has been in the order of 50 mA corresponding to about 50 mW power. When the capacitor is used together with an enzymatic power source, the leakage current must be as low as possible. Typical leakage current values have been in the order of 10 µA. CIMTEC 2010, 5th Forum on New Materials, Montecatini Terme, Italia, 13.-18.6.2010

Measurement Setup to Study the Electrode Potentials Separately in a Printed Biofuel Cell. [ECS Me... more Measurement Setup to Study the Electrode Potentials Separately in a Printed Biofuel Cell. [ECS Meeting Abstracts 1001, 420 (2010)]. Saara Tuurala, Maria H. Smolander, Matti Valkiainen, Anu Vaari, Ville-Mikko Ojala, Mikael Bergelin.

Oxidation of Metals

The present study investigates the early stages of the oxide layer degradation process of Sanicro... more The present study investigates the early stages of the oxide layer degradation process of Sanicro 28 (Fe31Cr27Ni) stainless steel when exposed to KCl at 450 and 535 °C. A novel combinatory technique was developed and utilized, where CA was employed as a qualitative method to follow the varying stages of the onset of the corrosion reaction. XPS was then used to identify the elemental distribution and depth profile within the oxide layer at each identified reaction stage, and the resulting change in surface morphology and the progress of the corrosion front was studied by SEM-EDXA. Additionally, the main mechanism behind the spreading of the reaction front was identified using a novel test approach. The corrosion reaction could be separated into several overlapping stages, with the process being initiated by the alternation of the oxide layer resulting in the loss of passivity, the formation of chromate within the oxide layer and finally the oxidation of the chromium and iron from und...

Sensing and Bio-Sensing Research, 2015

In this work, biobatteries assembled using roll-to-roll screen printed enzymatic electrodes were ... more In this work, biobatteries assembled using roll-to-roll screen printed enzymatic electrodes were characterised in terms of their electrical performance and storage stability. The enzymes and mediators used on the anode and cathode were glucose oxidase with ferrocenemethanol and laccase with ABTS, respectively. This study shows that besides rheological properties of enzyme inks used for the printing of the biobattery electrodes also adhesion of these electrodes to the printing substrate can be adjusted by varying the amount and composition of the binder in the ink. Another important observation is that the mediator has a strong impact on both the performance and the stability of the anode electrode. Consequently, electrochemical performance of biobatteries can be enhanced by adding fresh mediator into the battery during activation or by some other method preserving the activity of the mediator.

Solid State Phenomena, 2015

ABSTRACT

Journal of Applied Electrochemistry, 2014

ABSTRACT Production of printable enzymatic power sources was scaled up from laboratory to roll-to... more ABSTRACT Production of printable enzymatic power sources was scaled up from laboratory to roll-to-roll (R2R) pilot production. The anode and cathode enzymes were glucose oxidase (GOx) and laccase, respectively. The best laboratory-scale cells had a maximum power and energy density of 1.4 ± 0.1 µW cm−2 and 5.5 ± 0.2 µWh cm−2, respectively. These values are 5 and 28 times higher compared to our previously published values. The R2R-produced cells had a maximum power and energy density of 0.40 ± 0.03 µW cm−2 and 0.6 ± 0.1 µWh cm−2, respectively. This is 11 % of the best laboratory manufactured cells. It is suspected that the decrease in electrochemical performance originates from the lower mediator amount and higher drying temperature than that of the laboratory produced cells. However, the trials conducted in this work showed that printed enzymatic active layers can be fabricated and dried with a rotary screen-printing machine in R2R process. Hence, fully printed GOx//laccase power sources could be produced from R2R on a large scale for printed electronics applications.

Synthetic Metals, 2010

Poly(3,4-ethylenedioxythiophene) (PEDOT) films, with Cl−, NO3−, poly(styrene sulfonate) (PSS−) or... more Poly(3,4-ethylenedioxythiophene) (PEDOT) films, with Cl−, NO3−, poly(styrene sulfonate) (PSS−) or carbon nanotubes (CNTs) as counter ions, were electrochemically deposited onto indium tin oxide (ITO) glass from aqueous electrolyte. PEDOT film, with tetrafluoroborate anions (BF4−) as counter ions, was also electrochemically deposited on ITO glass from a propylene carbonate-based electrolyte. The effect of counter ions on the morphology of PEDOT films

Journal of Power Sources, 2003

Catalyst materials in form of inks, as half-MEAs and inside a polymer electrolyte membrane unit c... more Catalyst materials in form of inks, as half-MEAs and inside a polymer electrolyte membrane unit cell were characterized by cyclic voltammetry. Laboratory made Pt inks were modified with Ru, Os and Ru þ Ir and the methanol oxidation activity of the created surfaces was tested. A novel electrode, which enables the study of the oxygen reduction reaction on the cathode was introduced. With the measuring device it was possible to vary the oxygen content on the ink side and the proton activity of the electrolyte on the membrane side of a half-MEA. Catalyst layers based on Pt, Pt-Ru and Pt-Co inside a PEM-unit cell were also characterized in situ by cyclic voltammetry. The active surface areas were found to be linearly dependent on the Pt mass density in the catalyst layers. Approximately 30% of the Pt loading in the MEAs were electroactive. #

Journal of Power Sources, 2011

ABSTRACT Journal of Power Sources Vol.196 Nr.11, 4957-4964

Journal of Electroanalytical Chemistry, 2002

The behaviour of Os submonolayers on polycrystalline Pt was investigated by means of a flow cell ... more The behaviour of Os submonolayers on polycrystalline Pt was investigated by means of a flow cell of impinging jet type. Os was electrodeposited onto the electrode for various periods of time. From the loss in the hydrogen region charge it was possible to estimate the Os surface coverage. The activity of Os towards hydrogen adsorption was also studied by depositing the metal onto an Au electrode. An estimation of 40% hydrogen coverage for Os was made, which was taken into consideration in the determination of the Os coverage. Another method for estimating the surface coverage was also considered where the oxidation charge of OsO 4 was taken as a measure of the amount of Os present on the surface. It was also found that the deposition potential influences the voltammetry in the hydrogen region. A potential dependent preferential deposition onto Pt [110] and Pt[100] surface sites was observed. #

Enzyme and Microbial Technology, 2008

Laccases belong to the family of blue multicopper oxidases, which catalyze the four-electron redu... more Laccases belong to the family of blue multicopper oxidases, which catalyze the four-electron reduction of dioxygen to water concomitantly through the oxidation of phenolic and other aromatic compounds. They are potential enzymes in many applications including biofuel cells to produce electricity through chemical reactions. We have tested here the incorporation of a high redox potential laccase from Trametes hirsuta in different types of conducting inks to produce dry printed enzyme electrode layers. ABTS was used as the redox mediator to shuttle the electrons between the surface of the cathodic electrode and the enzyme active sites. Our results demonstrate that the dry printed layers maintained their enzymatic activity even after several months. Furthermore, fuel cell prototypes could be constructed utilising an optimized printed laccase-ABTS layer as the cathode, and printed Zn layer as the anode. Under humidity controlled conditions, a cell voltage between 0.8 and 0.6 V could be maintained for several days under a 2.2 k load. In addition, a corresponding stand-alone cell could be constructed where the cell voltage was maintained for 15 h under a load. These results offer a good starting point for further development of mass-producible, completely enzymatic printed biofuel cells.

Electrochimica Acta, 2012

An O 2 -consuming cathode for biofuel cell applications consisting of Trametes hirsuta laccase (T... more An O 2 -consuming cathode for biofuel cell applications consisting of Trametes hirsuta laccase (ThL) immobilized in an electropolymerized fine-tuned poly(3,4-ethylenedioxythiophene) (PEDOT) bilayer structure as the catalyst was studied. A NO 3 − -doped PEDOT layer with a relatively porous structure was used as the immobilization matrix on which the enzyme was added by solution casting. A capping layer of polystyrene sulphonate, PSS − -doped PEDOT was then electrodeposited on top of the first PEDOT layer in order to entrap the ThL between the layers. The PEDOT-NO 3 − /ThL/PEDOT-PSS − enzyme electrode is reported to be able to promote direct electron transfer (DET) between ThL and the current collector and it catalyzes the reduction of O 2 into water. The applicability of the PEDOT-NO 3 − /ThL/PEDOT-PSS − enzyme electrode structure on ITO glass with a geometrical surface area of 1 cm 2 as the electrode material was studied. The influence of different enzyme electrode fabrication parameters, such as the dopant ion used during electropolymerization, different combinations of PEDOT films, the thickness of both PEDOT layers and ThL loading on the enzyme electrode performance were investigated by chronoamperometric and cyclic voltammetric measurements. The optimum working pH for the enzyme electrode was found to be in the pH range 3.0-3.5. No enhanced cell performance was recorded when 2,2 -azinobis(3ethylbenzothiazoline-6-sulfonate) (ABTS) was used as mediator compared to DET in the PEDOT bilayer structure.

Electrochimica Acta, 1998

An impinging jet electrochemical¯ow cell developed for use with bead type electrodes was successf... more An impinging jet electrochemical¯ow cell developed for use with bead type electrodes was successfully employed in a surface structure sensitive study involving the processes of CO adsorption and oxidation on Pt(111) in 1.0 mol dm À3 H 2 SO 4 and HClO 4 . The¯ow cell enabled straightforward CO coverage control by means of varying the dosing time. Anion and hydrogen displacement charge curves with high potential resolution were obtained by means of CO adsorption and an electrolyte dependent ®ne structure was found. During the dosing of the electrolyte dissolved CO in the potential range 700±800 mV (vs. RHE) a slow delayed oxidation of adsorbed CO was noted and interpreted as being due to adsorption competition between CO and an oxygen containing species. A novel anion±anion displacement method was developed in which adsorbed bisulfate was replaced by perchlorate or water. The negative current transient obtained indicated desorption of bisulfate. #

Electrochimica Acta, 2012

ABSTRACT Printed supercapacitors were prepared to be applied as a part of a hybrid power source i... more ABSTRACT Printed supercapacitors were prepared to be applied as a part of a hybrid power source in printed electronics applications. The use of non-toxic materials was preferred. The supercapacitor structure consisting of current collectors and activated carbon electrodes was applied on paperboard substrate using silver, graphite and activated carbon inks. Aqueous electrolytes with NaCl salt limit the maximum potential to about 1.2 V but are environmentally friendly and provide low equivalent series resistance (ESR).The capacitance values of our printed supercapacitors were typically 0.1–0.5 F. With 2 cm2 geometrical active area the ESR was below 1 Ω which is acceptable for 50 mA current output. The efficiency with 50 mA charge and discharge current was typically about 90% and with 10 mA about 95%.

Measurement Setup to Study the Electrode Potentials Separately in a Printed Biofuel Cell. [ECS Me... more Measurement Setup to Study the Electrode Potentials Separately in a Printed Biofuel Cell. [ECS Meeting Abstracts 1001, 420 (2010)]. Saara Tuurala, Maria H. Smolander, Matti Valkiainen, Anu Vaari, Ville-Mikko Ojala, Mikael Bergelin.

Biosensors and Bioelectronics, 2012

We report on the fabrication and characterisation of a gold-nanoparticle (AuNP)-based mediatorles... more We report on the fabrication and characterisation of a gold-nanoparticle (AuNP)-based mediatorless sugar/oxygen biofuel cell (BFC) operating in neutral sugar-containing buffers and human physiological fluids, such as blood and plasma. First, Corynascus thermophilus cellobiose dehydrogenase (CtCDH) and Myrothecium verrucaria bilirubin oxidase (MvBOx), used as anodic and cathodic bioelements, respectively, were immobilised on gold electrodes modified with 20 nm AuNPs. Detailed characterisation and optimisation of a new CDH/AuNP-based bioanode were performed and the following fundamental parameters were obtained: (i) the redox potential of the haem-containing centre of the enzyme was measured to be 75 mV vs. NHE, (ii) the surface coverage of CtCDH was found to be 0.65 pmol cm −2 corresponding to a sub-monolayer coverage of the thiol-modified AuNPs by the enzyme, (iii) a turnover number for CtCDH immobilised on thiol-modified AuNPs was calculated to be ca. 0.5 s −1 , and (iv) the maximal current densities as high as 40 A cm −2 were registered in sugar-containing neutral buffers. Second, both biomodified electrodes, namely the CtCDH/AuNP-based bioanode and the MvBOx/AuNP-based biocathode, were combined into a functional BFC and the designed biodevices were carefully investigated. The following characteristics of the mediator-, separator-and membrane-less, miniature BFC were obtained: in phosphate buffer; an open-circuit voltage of 0.68 V, a maximum power density of 15 W cm −2 at a cell voltage of 0.52 V and in human blood; an open-circuit voltage of 0.65 V, a maximum power density of 3 W cm −2 at a cell voltage of 0.45 V, respectively. The estimated half-lives of the biodevices were found to be >12, <8, and <2 h in a sugar-containing buffer, human plasma, and blood, respectively. The basic characteristics of mediatorless sugar/oxygen BFCs were significantly improved compared with previously designed biodevices, because of the usage of three-dimensional AuNP-modified electrodes. (S. Shleev). URL: http://www.mah.se/Shleev (S. Shleev). 1 X. Wang and M. Falk equally contributed to the present work.

Advances in Science and Technology, 2010

ABSTRACT Advances in Science and Technology Vol.72, 331-336 Low cost printable power sources are ... more ABSTRACT Advances in Science and Technology Vol.72, 331-336 Low cost printable power sources are needed e.g. in sensors and RFID applications. As manufacturing method printing techniques are preferred in order to keep the costs low. The materials should also be easily disposable. Enzymatic bio-fuel cells are an alternative for printable primary batteries. Since one drawback of bio-fuel cells is their low power, we have developed supercapacitors that can be combined with enzymatic bio-fuel cells to provide the power peaks necessary in the applications. The materials for the supercapacitors have been chosen to be compatible with the fuel cell and with printing methods, e.g. the activated carbon powder in the electrodes was bound with chitosan. As printing substrates we have used paperboards. The current collectors have been made of graphite and metal inks. Since the voltage requirement is limited to approximately 1 V, aqueous electrolytes have been used. Printed supercapacitors of various sizes have been prepared. The geometrical electrode areas have been between 0.5 and 2 cm2. The maximum feasible output current has been in the order of 50 mA corresponding to about 50 mW power. When the capacitor is used together with an enzymatic power source, the leakage current must be as low as possible. Typical leakage current values have been in the order of 10 µA. CIMTEC 2010, 5th Forum on New Materials, Montecatini Terme, Italia, 13.-18.6.2010