TY  - JOUR
A1  - Kammer, Stefan
A1  - Kelling, Alexandra
A1  - Baier, Heiko
A1  - Mickler, Wulfhard
A1  - Dosche, Carsten
A1  - Rurack, Knut
A1  - Kapp, Andreas
A1  - Lisdat, Fred
A1  - Holdt, Hans-Jürgen
T1  - 2,11-dialkylated 1,12-diazaperylene copper(I) complexes : first supramolecular column assemblies by pi-pi stacking between homoleptic tetrahedral metal complexes, exhibiting low-energy MLCT transitions
N2  - 2,11-Dialkylated 1,12-diazaperylenes (alkyl = Me, Et, iPr) dmedap, detdap and dipdap have been synthesized by reductive cyclization of 3,3-dialkylated 1,1-biisoquinolines 3a-c, resulting in the first copper(I) complexes of a large- surface ligand. The new copper(I) complexes show low-energy MLCT absorptions unprecedented for bis(-diimin)copper(I) complexes. The solid structures of the complexes[Cu(dipdap)2]BF4·CH2Cl2·1.5H2O, [Cu(dipdap)2]OTf·CH2Cl2, [Cu(dipdap)2]I·C2H4Cl2·THF·2H2O, [Cu(dmedap)2]OTf and [Cu(dipdap)2]AQSO3·H2O (AQSO3 = sodium 9,10-dihydro-9,10-dioxo-2- anthracenesulfonate) are reported. In [Cu(dipdap)2]BF4·CH2Cl2·1.5H2O, each copper(I) complex cation interacts with two others by - stacking interactions forming a novel supramolecular column structural motif running along the crystallographic c axis. In the crystalline compound [Cu(dipdap)2]AQSO3·H2O, aggregation between two complex cations and two additional anions by - stacking interactions is observed, leading to a tetrameric assembly. Furthermore, the three complex compounds [Cu(L)2]BF4 (L = dmedap, detdap, dipdap) were tested for sensory applications in aqueous buffer solutions in electrochemical studies of the complex immobilized on glassy carbon electrodes.
Y1  - 2009
UR  - http://www3.interscience.wiley.com/journal/27721/home
U6  - https://doi.org/10.1002/ejic.200900695
SN  - 1434-1948
ER  - 
TY  - JOUR
A1  - Sarauli, David
A1  - Peters, Kristina
A1  - Xu, Chenggang
A1  - Schulz, Burkhard
A1  - Fattakhova-Rohlfing, Dina
A1  - Lisdat, Fred
T1  - 3D-Electrode architectures for enhanced direct bioelectrocatalysis of pyrroloquinoline quinone-dependent glucose dehydrogenase
JF  - ACS applied materials & interfaces
N2  - We report on the fabrication of a complex electrode architecture for efficient direct bioelectrocatalysis. In the developed procedure, the redox enzyme pyrroloquinoline quinone-dependent glucose dehydrogenase entrapped in a sulfonated polyaniline [poly(2-methoxyaniline-5-sulfonic acid)-co-aniline] was immobilized on macroporous indium tin oxide (macroITO) electrodes. The use of the 3D-conducting scaffold with a large surface area in combination with the conductive polymer enables immobilization of large amounts of enzyme and its efficient communication with the electrode, leading to enhanced direct bioelectrocatalysis. In the presence of glucose, the fabricated bioelectrodes show an exceptionally high direct bioelectrocatalytical response without any additional mediator. The catalytic current is increased more than 200-fold compared to planar ITO electrodes. Together with a high long-term stability (the current response is maintained for >90% of the initial value even after 2 weeks of storage), the transparent 3D macroITO structure with a conductive polymer represents a valuable basis for the construction of highly efficient bioelectronic units, which are useful as indicators for processes liberating glucose and allowing optical and electrochemical transduction.
KW  - 3D electrode structures
KW  - macroITO
KW  - conductive polymer
KW  - PQQ-GDH
KW  - direct bioelectrocatalysis
KW  - bioelectrochemistry
Y1  - 2014
U6  - https://doi.org/10.1021/am5046026
SN  - 1944-8244
VL  - 6
IS  - 20
SP  - 17887
EP  - 17893
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - GEN
A1  - Sarauli, David
A1  - Xu, Chenggang
A1  - Dietzel, Birgit
A1  - Schulz, Burkhard
A1  - Lisdat, Fred
T1  - A multilayered sulfonated polyaniline network with entrapped pyrroloquinoline quinone-dependent glucose dehydrogenase
BT  - tunable direct bioelectrocatalysis
N2  - A feasible approach to construct multilayer films of sulfonated polyanilines – PMSA1 and PABMSA1 – containing different ratios of aniline, 2-methoxyaniline-5-sulfonic acid (MAS) and 3-aminobenzoic acid (AB), with the entrapped redox enzyme pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH) on Au and ITO electrode surfaces, is described. The formation of layers has been followed and confirmed by electrochemical impedance spectroscopy (EIS), which demonstrates that the multilayer assembly can be achieved in a progressive and uniform manner. The gold and ITO electrodes subsequently modified with PMSA1:PQQ-GDH and PABMSA1 films are studied by cyclic voltammetry (CV) and UV-Vis spectroscopy which show a significant direct bioelectrocatalytical response to the oxidation of the substrate glucose without any additional mediator. This response correlates linearly with the number of deposited layers. Furthermore, the constructed polymer/enzyme multilayer system exhibits a rather good long-term stability, since the catalytic current response is maintained for more than 60% of the initial value even after two weeks of storage. This verifies that a productive interaction of the enzyme embedded in the film of substituted polyaniline can be used as a basis for the construction of bioelectronic units, which are useful as indicators for processes liberating glucose and allowing optical and electrochemical transduction.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 275 
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-98744
ER  - 
TY  - JOUR
A1  - Sarauli, David
A1  - Xu, Chenggang
A1  - Dietzel, Birgit
A1  - Schulz, Burkhard
A1  - Lisdat, Fred
T1  - A multilayered sulfonated polyaniline network with entrapped pyrroloquinoline quinone-dependent glucose dehydrogenase: tunable direct bioelectrocatalysis
JF  - Journal of materials chemistry : B, Materials for biology and medicine
N2  - A feasible approach to construct multilayer films of sulfonated polyanilines - PMSA1 and PABMSA1 containing different ratios of aniline, 2-methoxyaniline-5-sulfonic acid (MAS) and 3-aminobenzoic acid (AB), with the entrapped redox enzyme pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH) on Au and ITO electrode surfaces, is described. The formation of layers has been followed and confirmed by electrochemical impedance spectroscopy (EIS), which demonstrates that the multilayer assembly can be achieved in a progressive and uniform manner. The gold and ITO electrodes subsequently modified with PMSA1:PQQ-GDH and PABMSA1 films are studied by cyclic voltammetry (CV) and UV-Vis spectroscopy which show a significant direct bioelectrocatalytical response to the oxidation of the substrate glucose without any additional mediator. This response correlates linearly with the number of deposited layers. Furthermore, the constructed polymer/enzyme multilayer system exhibits a rather good long-term stability, since the catalytic current response is maintained for more than 60% of the initial value even after two weeks of storage. This verifies that a productive interaction of the enzyme embedded in the film of substituted polyaniline can be used as a basis for the construction of bioelectronic units, which are useful as indicators for processes liberating glucose and allowing optical and electrochemical transduction.
Y1  - 2014
U6  - https://doi.org/10.1039/c4tb00336e
SN  - 2050-750X
SN  - 2050-7518
VL  - 2
IS  - 21
SP  - 3196
EP  - 3203
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Beissenhirtz, Moritz Karl
A1  - Scheller, Frieder W.
A1  - Lisdat, Fred
T1  - A superoxide sensor based on a multilayer cytochrome c electrode
N2  - A novel multilayer cytochrome c electrode for the quantification of superoxide radical concentrations is introduced. The electrode consists of alternating layers of cytochrome c and poly(aniline(sulfonic acid)) on a gold wire electrode. The formation of multilayer structures was proven by SPR experiments. Assemblies with 2-15 protein layers showed electrochemical communication with the gold electrode. For every additional layer, a substantial increase in electrochemically active cytochrome c (cyt. c) was found. For electrodes of more than 10 layers, the increase was more than 1 order of magnitude as compared to monolayer electrode systems. Thermodynamic and kinetic parameters of the electrodes were characterized. The mechanism of electron transfer within the multilayer assembly was studied, with results suggesting a protein-protein electron-transfer model. Electrodes of 2-15 layers were applied to the in vitro quantification of enzymatically generated superoxide, showing superior sensitivity as compared to a monolayer-based sensor. An electrode with 6 cyt. c/PASA layers showed the highest sensitivity of the systems studied, giving an increase in sensitivity of half an order of magnitude versus the that of the monolayer electrode. The stability of the system was optimized using thermal treatment, resulting in no loss in sensor signal or protein loading after 10 successive measurements or 2 days of storage
Y1  - 2004
SN  - 0003-2700
ER  - 
TY  - JOUR
A1  - Ignatov, S.
A1  - Shishniashvili, D.
A1  - Ge, Bixia
A1  - Scheller, Frieder W.
A1  - Lisdat, Fred
T1  - Amperometric biosensor based on a functionalized gold electrode for the detection of antioxidants
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Lisdat, Fred
A1  - Ge, Bixia
A1  - Reszka, R.
A1  - Kozniewska, E.
T1  - An electrochemical method for quantification of the radical scavening activity of SOD
Y1  - 1999
ER  - 
TY  - JOUR
A1  - Lisdat, Fred
A1  - Utepbergenov, D.
A1  - Haseloff, R. F.
A1  - Blasig, Ingolf E.
A1  - Stöcklein, Walter F. M.
A1  - Scheller, Frieder W.
A1  - Brigelius-Flohé, Regina
T1  - An optical method for the detection of oxidative stress using protein-RNA interaction
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
A1  - Lisdat, Fred
A1  - Wollenberger, Ursula
T1  - Application of electrically contacted enzymes for biosensors
Y1  - 2005
SN  - 3-527- 30690-0
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
A1  - Wollenberger, Ursula
A1  - Lei, Chenghong
A1  - Jin, Wen
A1  - Ge, Bixia
A1  - Lehmann, Claudia
A1  - Lisdat, Fred
A1  - Fridman, Vadim
T1  - Bioelectrocatalysis by redox enzymes at modified electrodes
Y1  - 2002
UR  - www.elsevier.nl/inca/publications/6/0/1/3/4/7/index.htt
ER  - 
TY  - JOUR
A1  - Beissenhirtz, Moritz Karl
A1  - Kwan, R. C. H.
A1  - Ko, K. M.
A1  - Renneberg, Reinhard
A1  - Scheller, Frieder W.
A1  - Lisdat, Fred
T1  - Comparing in vitro electrochemical measurement of superoxide scavenging activity with an in vivo assessment of antioxidant potential in Chinese tonifying herbs
N2  - The in vitro superoxide scavenging activity (as determined by electrochemical measurement) and the in vivo antioxidant potential (as determined by a mouse model of carbon tetrachloride (CCl4) hepatotoxicity) of methanolic extracts prepared from 10 Chinese tonifying herbs were compared. Electrochemical measurement using a cytochrome c (Cyt. c) sensor showed that all of the tested herbal extracts exhibited a medium superoxide scavenging activity of different potency, as indicated by their IC50 values. The in vivo measurement demonstrated that 80% of the herbal extracts displayed in vivo antioxidant potential, as assessed by the percentage of protection of the activity of plasma alanine aminotransferases and the hepatic glutathione regeneration capacity under CCl4-intoxicated condition. Although the in vitro antioxidant activity did not correlate quantitatively with the in vivo antioxidant potential, for 8 out of 10 samples a similar tendency was found. The rapid amperometric assessment of antioxidant potential by Cyt. c sensor may offer a convenient and direct method for screening as well as the quality control of herbal products. Copyright (C) 2004 John Wiley Sons, Ltd
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Riedel, M.
A1  - Sabir, N.
A1  - Scheller, Frieder W.
A1  - Parak, Wolfgang J.
A1  - Lisdat, Fred
T1  - Connecting quantum dots with enzymes
BT  - mediator-based approaches for the light-directed read-out of glucose and fructose oxidation
JF  - Nanoscale
N2  - The combination of the biocatalytic features of enzymes with the unique physical properties of nanoparticles in a biohybrid system provides a promising approach for the development of advanced bioelectrocatalytic devices. This study describes the construction of photoelectrochemical signal chains based on CdSe/ZnS quantum dot (QD) modified gold electrodes as light switchable elements, and low molecular weight redox molecules for the combination with different biocatalysts. Photoelectrochemical and photoluminescence experiments verify that electron transfer can be achieved between the redox molecules hexacyanoferrate and ferrocene, and the QDs under illumination. Since for both redox mediators a concentration dependent photocurrent change has been found, light switchable enzymatic signal chains are built up with fructose dehydrogenase (FDH) and pyrroloquinoline quinone-dependent glucose dehydrogenase ((PQQ) GDH) for the detection of sugars. After immobilization of the enzymes at the QD electrode the biocatalytic oxidation of the substrates can be followed by conversion of the redox mediator in solution and subsequent detection at the QD electrode. Furthermore, (PQQ) GDH has been assembled together with ferrocenecarboxylic acid on top of the QD electrode for the construction of a funtional biohybrid architecture, showing that electron transfer can be realized from the enzyme over the redox mediator to the QDs and subsequently to the electrode in a completely immobilized fashion. The results obtained here do not only provide the basis for light-switchable biosensing and bioelectrocatalytic applications, but may also open the way for self-driven point-of-care systems by combination with solar cell approaches (power generation at the QD electrode by enzymatic substrate consumption).
Y1  - 2017
U6  - https://doi.org/10.1039/c7nr00091j
SN  - 2040-3364
SN  - 2040-3372
VL  - 9
SP  - 2814
EP  - 2823
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Lei, Chenghong
A1  - Lisdat, Fred
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
T1  - Cytochrome c : Clay-modified electrode
Y1  - 1999
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
A1  - Jin, Wen
A1  - Ehrentreich-Förster, Eva
A1  - Ge, Bixia
A1  - Lisdat, Fred
A1  - Büttemeyer, R.
A1  - Wollenberger, Ursula
T1  - Cytochrome c based superoxide sensor for in vivo application
Y1  - 1999
ER  - 
TY  - JOUR
A1  - Ge, Bixia
A1  - Meyer, T.
A1  - Schöning, M. J.
A1  - Wollenberger, Ursula
A1  - Lisdat, Fred
T1  - Cytochrome c from chromatium vinosum on gold electrodes
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Wegerich, Franziska
A1  - Turano, Paola
A1  - Allegrozzi, Marco
A1  - Moehwald, Helmuth
A1  - Lisdat, Fred
T1  - Cytochrome c mutants for superoxide biosensors
N2  - The effect of introducing positive charges (lysines) in human cytochrome c (cyt c) on the redox properties and reaction rates of cyt c with superoxide radicals was studied. The mutated forms of this electron-transfer protein are used as sensorial recognition elements for the amperometric detection of the reactive oxygen radical. The proteins were prepared by site-directed mutagenesis focusing on amino acids near the heme edge. The 11 mutants of human cyt c expressed in the course of this research have been characterized by UV-vis spectroscopy, circular dichroism, and NMR spectroscopy to verify overall structure integrity as well as axial coordination of the heme iron. The mutants are investigated voltammetrically using promoter-modified gold electrodes with respect to redox activity and formal redox potential. The rate constants for the reaction with superoxide have been determined spectrophotometrically. Four mutants show a higher reaction rate with the radical as compared to the wild type. These mutants are used for the construction of superoxide sensors based on thiol-modified gold electrodes and covalently fixed proteins. We found that the E66K mutant-based electrode has a clearly higher sensitivity in comparison with the wild-type-based sensor while retaining the high selectivity and showing a good storage stability.
Y1  - 2009
UR  - http://pubs.acs.org/journal/ancham
U6  - https://doi.org/10.1021/Ac802571h
SN  - 0003-2700
ER  - 
TY  - JOUR
A1  - Kepplinger, Christian
A1  - Lisdat, Fred
A1  - Wollenberger, Ursula
T1  - Cytochrome c/polyelectrolyte multilayers investigated by E-QCM-D - effect of temperature on the assembly structure
JF  - Langmuir
N2  - Protein multilayers, consisting of cytochrome c (cyt c) and poly(aniline sulfonic acid) (PASA), are investigated by electrochemical quartz crystal microbalance with dissipation monitoring (E-QCM-D). This technique reveals that a four-bilayer assembly has rather rigid properties. A thickness of 16.3 +/- 0.8 nm is calculated with the Sauerbrey equation and is found to be in good agreement with a viscoelastic model. The electroactive amount of cyt c is estimated by the deposited mass under the assumption of 50% coupled water. Temperature-induced stabilization of the multilayer assembly has been investigated in the temperature range between 30 and 45 degrees C. The treatment results in a loss of material and a contraction of the film. The electroactive amount of cyt c also decreases during heating and remains constant after the cooling period. The contraction of the film is accompanied by the enhanced stability of the assembly. In addition, it is found that cyt c and PASA can be assembled at higher temperatures, resulting in the formation of multilayer systems with less dissipation.
Y1  - 2011
U6  - https://doi.org/10.1021/la200860p
SN  - 0743-7463
VL  - 27
IS  - 13
SP  - 8309
EP  - 8315
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Krylov, Andrey V.
A1  - Pfeil, Wolfgang
A1  - Lisdat, Fred
T1  - Denaturation and renaturation of cytochrome c immobilized on gold electrodes in DMSO-containing buffers
N2  - Cytochrome c (cyt c) was immobilized on surface-modified gold electrodes using a self-assembling approach. The resulting cyt c electrode was studied using cyclic voltammetry. Compared to pure phosphate buffer, cyt c electrodes exhibited in DMSO-containing solutions lower oxidation and reduction peak currents, which originated from a decrease in the addressable electro-active amount of the surface-immobilized protein. This is associated with the process of protein denaturation. The denaturation kinetics can be described by a sum of two processes with time constants differing by more than one order of magnitude. The subsequent change of the aqueous/organic medium back to a pure aqueous buffer resulted in a shift of the formal potential to its initial value and a partial recovery of the peak current. This can be attributed to the renaturation of the cyt c. The extent of renaturation depended on the organic solvent/water ratio of the mixture used. The kinetics of protein renaturation were similar to those of the denaturation process. (C) 2004 Elsevier B.V. All rights reserved
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Ignatov, S.
A1  - Ge, Bixia
A1  - Scheller, Frieder W.
A1  - Lisdat, Fred
T1  - Detection of the antioxidant activity detection of flavonoids by using superoxide sensor
Y1  - 2001
SN  - 1-58603-164-3
ER  - 
TY  - JOUR
A1  - Sarauli, David
A1  - Xu, Chenggang
A1  - Dietzel, Birgit
A1  - Schulz, Burkhard
A1  - Lisdat, Fred
T1  - Differently substituted sulfonated polyanilines - the role of polymer compositions in electron transfer with pyrroloquinoline quinone-dependent glucose dehydrogenase
JF  - Acta biomaterialia
N2  - Sulfonated polyanilines have become promising building blocks in the construction of biosensors, and therefore we use here differently substituted polymer forms to investigate the role of their structural composition and properties in achieving a direct electron transfer with the redox enzyme pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH). To this end, new copolymers containing different ratios of 2-methoxyaniline-5-sulfonic acid (MAS), 3-aminobenzenesulfonic acid (ABS) and 3-aminobenzoic acid (AB) units have been chemically synthesized. All polymers have been studied with respect to their ability to react directly with PQQ-GDH. This interaction has been monitored initially in solution, and subsequently on electrode surfaces. The results show that only copolymers with MAS and aniline units can directly react with PQQ-GDH in solution; the background can be mainly ascribed to the emeraldine salt redox state of the polymer, allowing rather easy reduction. However, when polymers and the enzyme are immobilized on the surface of carbon nanotube-containing electrodes, direct bioelectrocatalysis is also feasible in the case of copolymers composed of ABS/AB and MAS/AB units, existing initially in pernigraniline base form. This verifies that a productive interaction of the enzyme with differently substituted polymers is feasible when the electrode potential can be used to drive the reaction towards the oxidation of the substrate-reduced enzyme. These results clearly demonstrate that enzyme electrodes based on sulfonated polyanilines and direct bioelectrocatalysis can be successfully constructed.
KW  - Sulfonated polyaniline
KW  - PQQ-dependent glucose dehydrogenase
KW  - Direct electron transfer
KW  - Immobilization
KW  - Bioelectrocatalysis
Y1  - 2013
U6  - https://doi.org/10.1016/j.actbio.2013.06.008
SN  - 1742-7061
VL  - 9
IS  - 9
SP  - 8290
EP  - 8298
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Beissenhirtz, Moritz Karl
A1  - Scheller, Frieder W.
A1  - Stöcklein, Walter F. M.
A1  - Kurth, D.
A1  - Möhwald, Helmuth
A1  - Lisdat, Fred
T1  - Electroactive cytochrome c multilayers within a polyelectrolyte assembly
Y1  - 2004
ER  - 
TY  - GEN
A1  - Spricigo, Roberto
A1  - Dronov, Roman
A1  - Lisdat, Fred
A1  - Leimkühler, Silke
A1  - Scheller, Frieder W.
A1  - Wollenberger, Ursula
T1  - Electrocatalytic sulfite biosensor with human sulfite oxidase co-immobilized with cytochrome c in a polyelectrolyte-containing multilayer
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - An efficient electrocatalytic biosensor for sulfite detection was developed by co-immobilizing sulfite oxidase and cytochrome c with polyaniline sulfonic acid in a layer-by-layer assembly. QCM, UV-Vis spectroscopy and cyclic voltammetry revealed increasing loading of electrochemically active protein with the formation of multilayers. The sensor operates reagentless at low working potential. A catalytic oxidation current was detected in the presence of sulfite at the modified gold electrode, polarized at +0.1 V ( vs. Ag/AgCl 1 M KCl). The stability of the biosensor performance was characterized and optimized. A 17-bilayer electrode has a linear range between 1 and 60 mu M sulfite with a sensitivity of 2.19 mA M-1 sulfite and a response time of 2 min. The electrode retained a stable response for 3 days with a serial reproducibility of 3.8% and lost 20% of sensitivity after 5 days of operation. It is possible to store the sensor in a dry state for more than 2 months. The multilayer electrode was used for determination of sulfite in unspiked and spiked samples of red and white wine. The recovery and the specificity of the signals were evaluated for each sample.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 945 
KW  - bioelectrocatalysis
KW  - sulfite
KW  - sulfite oxidase
KW  - cytochrome c
KW  - multilayer
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-431176
SN  - 1866-8372
IS  - 945
SP  - 225
EP  - 233
ER  - 
TY  - JOUR
A1  - Spricigo, Roberto
A1  - Dronov, Roman
A1  - Lisdat, Fred
A1  - Leimkühler, Silke
A1  - Scheller, Frieder W.
A1  - Wollenberger, Ursula
T1  - Electrocatalytic sulfite biosensor with human sulfite oxidase co-immobilized with cytochrome c in a polyelectrolyte-containing multilayer
N2  - An efficient electrocatalytic biosensor for sulfite detection was developed by co-immobilizing sulfite oxidase and cytochrome c with polyaniline sulfonic acid in a layer-by-layer assembly. QCM, UV-Vis spectroscopy and cyclic voltammetry revealed increasing loading of electrochemically active protein with the formation of multilayers. The sensor operates reagentless at low working potential. A catalytic oxidation current was detected in the presence of sulfite at the modified gold electrode, polarized at +0.1 V ( vs. Ag/AgCl 1 M KCl). The stability of the biosensor performance was characterized and optimized. A 17-bilayer electrode has a linear range between 1 and 60 mu M sulfite with a sensitivity of 2.19 mA M-1 sulfite and a response time of 2 min. The electrode retained a stable response for 3 days with a serial reproducibility of 3.8% and lost 20% of sensitivity after 5 days of operation. It is possible to store the sensor in a dry state for more than 2 months. The multilayer electrode was used for determination of sulfite in unspiked and spiked samples of red and white wine. The recovery and the specificity of the signals were evaluated for each sample.
Y1  - 2009
UR  - http://www.springerlink.com/content/100417
U6  - https://doi.org/10.1007/s00216-008-2432-y
SN  - 1618-2642
ER  - 
TY  - JOUR
A1  - Kapp, A.
A1  - Beissenhirtz, Moritz Karl
A1  - Geyer, F.
A1  - Scheller, F.
A1  - Viezzoli, Maria Silvia
A1  - Lisdat, Fred
T1  - Electrochemical and sensorial behavior of SOD mutants immobilized on gold electrodes in aqueous/organic solvent mixtures
JF  - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis
N2  - A cysteine mutant of a monomeric human Cu, Zn-SOD (Glycine 61, Serine 142) has been immobilized directly on gold electrodes using the thiol groups introduced. The electrochemical behavior of the surface confined protein was studied in mixtures of aqueous buffer and DMSO up to an organic solvent content of 60%. The formal potential was found to be rather independent of the DMSO content. However, half peak width increased and the redoxactive amount clearly decreased with raising DMSO content. In addition, the kinetics of the heterogeneous electron transfer became slower; but still a quasireversible electrochemical conversion of the mutant SOD was feasible. Thus, the electrodes were applied for sensorial superoxide detection. At a potential of +220 mV vs. Ag/AgCl advantage was taken of the partial oxidation reaction of the enzyme. A defined superoxide signal was obtained in solutions up to 40% DMSO. The sensitivity of the mutant electrodes decreased linearly with the organic solvent content in solution but was still higher compared to conventional cyt.c based sensors. At DMSO concentrations higher than 40% no sensor response was detected.
KW  - SOD
KW  - mutants
KW  - gold electrodes
KW  - DMSO
KW  - electrochemistry
Y1  - 2006
U6  - https://doi.org/10.1002/elan.200603620
SN  - 1040-0397
VL  - 18
SP  - 1909
EP  - 1915
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Kapp, Andreas
A1  - Beissenhirtz, Moritz Karl
A1  - Geyer, F.
A1  - Scheller, Frieder W.
A1  - Viezzoli, Maria Silvia
A1  - Lisdat, Fred
T1  - Electrochemical and sensorial behaviour of SOD mutants immobilized on gold electrodes in aqueous / organic solvent mixtures
Y1  - 2006
UR  - http://www3.interscience.wiley.com/cgi-bin/jhome/26571/
U6  - https://doi.org/10.1002/elan.200603620
SN  - 1040-0397
ER  - 
TY  - JOUR
A1  - Lisdat, Fred
A1  - Ge, Bixia
A1  - Stöcklein, Walter F. M.
A1  - Scheller, Frieder W.
A1  - Meyer, T.
T1  - Electrochemical behaviour and nitric oxides interaction of immobilised cytochrome c from Rhodocyclus gelatinosus
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Fandrich, Artur
A1  - Buller, Jens
A1  - Schäfer, Daniel
A1  - Wischerhoff, Erik
A1  - Laschewsky, André
A1  - Lisdat, Fred
T1  - Electrochemical characterization of a responsive macromolecular interface on gold
JF  - Physica status solidi : A, Applications and materials science
N2  - This study reports on the investigation of a thermoresponsive polymer as a thin film on electrodes and the influence of coupling a peptide and an antibody to the film. The utilized polymer from the class of poly(oligoethylene glycol)-methacrylate polymers (poly(OEGMA)) with carboxy functions containing side chains was synthesized and properly characterized in aqueous solutions. The dependence of the cloud point on the pH of the surrounding media is discussed. The responsive polymer was immobilized on gold electrodes as shown by electrochemical, quartz crystal microbalance (QCM), and atomic force microscopy (AFM) techniques. The temperature dependent behavior of the polymer covalently grafted to gold substrates is investigated using cyclic voltammetry (CV) in ferro-/ferricyanide solution. Significant changes in the slope of the temperature-dependence of the voltammetric peak current and the peak separation values clearly indicate the thermally induced conformational change on the surface. Finally, a biorecognition reaction between a short FLAG peptide (N-Asp-Tyr-Lys-Asp-Asp-Asp-Asp-Lys-C) covalently immobilized on the polymer interface and the corresponding IgG antibody was performed. The study shows that the responsiveness of the electrode is retained after peptide coupling and antibody binding, although the response is diminished.
KW  - biorecognition reactions
KW  - cyclic voltammetry
KW  - electrodes
KW  - gold
KW  - interfaces
KW  - responsive polymers
Y1  - 2015
U6  - https://doi.org/10.1002/pssa.201431698
SN  - 1862-6300
SN  - 1862-6319
VL  - 212
IS  - 6
SP  - 1359
EP  - 1367
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Fandrich, Artur
A1  - Buller, Jens
A1  - Wischerhoff, Erik
A1  - Laschewsky, André
A1  - Lisdat, Fred
T1  - Electrochemical detection of the thermally induced phase transition of a thin stimuli-responsive polymer film
JF  - ChemPhysChem : a European journal of chemical physics and physical chemistry
KW  - cyclic voltammetry
KW  - electrochemical impedance spectroscopy
KW  - polymers
KW  - surface chemistry
KW  - surface plasmon resonance
Y1  - 2012
U6  - https://doi.org/10.1002/cphc.201100924
SN  - 1439-4235
VL  - 13
IS  - 8
SP  - 2020
EP  - 2023
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Fridman, Vadim
A1  - Wollenberger, Ursula
A1  - Bogdanovskaya, V. A.
A1  - Lisdat, Fred
A1  - Ruzgas, T.
A1  - Lindgren, A.
A1  - Gorton, Lo
A1  - Scheller, Frieder W.
T1  - Electrochemical investigation of cellobiose oxidation by cellobiose dehydrogenase in the presence of cytochrome c as mediator
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Ju, Huangxian
A1  - Liu, Songqin
A1  - Ge, Bixia
A1  - Lisdat, Fred
A1  - Scheller, Frieder W.
T1  - Electrochemistry of cytochrome c immobilized on colloidal gold modified carbon paste electrodes and its electrocatalytic activity
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Ge, Bixia
A1  - Scheller, Frieder W.
A1  - Lisdat, Fred
T1  - Electrochemistry of immobilized CuZnSOD and FeSOD and their interaction with superoxide radicals
N2  - Copper, zinc superoxide dismutase (CuZnSOD) from bovine erythrocytes and iron superoxide dismutase from Escherichia coli (FeSOD) were immobilized on 3-mercaptopropionic acid (MPA)-modified gold electrodes, respectively. The characterization of the SOD electrodes showed a quasi-reversible, electrochemical redox behavior with a formal potential of 47 ñ 4 mV and -154 ñ 5 mV (vs. Ag/AgCl, 1 M KCl) for surface adsorbed CuZnSOD and FeSOD, respectively. The heterogeneous electron transfer rate constants were determined to be about 65 and 35/s, respectively. Covalent fixation of both SODs was also feasible with only slight changes in the formal potential. The interaction of superoxide radicals (O2-) with the SOD electrode was investigated. No catalytic current could be observed. However, due to the fast cyclic reaction of SOD with superoxide, the communication of the protein with the electrode was strongly influenced. The amperometric detection of superoxide radicals is discussed.
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Heinsohn, Natascha Katharina
A1  - Niedl, Robert Raimund
A1  - Anielski, Alexander
A1  - Lisdat, Fred
A1  - Beta, Carsten
T1  - Electrophoretic mu PAD for purification and analysis of DNA samples
JF  - Biosensors : open access journal
N2  - In this work, the fabrication and characterization of a simple, inexpensive, and effective microfluidic paper analytic device (mu PAD) for monitoring DNA samples is reported. The glass microfiber-based chip has been fabricated by a new wax-based transfer-printing technique and an electrode printing process. It is capable of moving DNA effectively in a time-dependent fashion. The nucleic acid sample is not damaged by this process and is accumulated in front of the anode, but not directly on the electrode. Thus, further DNA processing is feasible. The system allows the DNA to be purified by separating it from other components in sample mixtures such as proteins. Furthermore, it is demonstrated that DNA can be moved through several layers of the glass fiber material. This proof of concept will provide the basis for the development of rapid test systems, e.g., for the detection of pathogens in water samples.
KW  - microfluidic paper analytic device (mu PAD)
KW  - patterning glass microfiber
KW  - fiber-electrophoresis chip
KW  - DNA
KW  - imprinted electrodes
KW  - cross layer chip
KW  - polymerase chain reaction (PCR)
KW  - purification
Y1  - 2022
U6  - https://doi.org/10.3390/bios12020062
SN  - 2079-6374
VL  - 12
IS  - 2
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Beissenhirtz, Moritz Karl
A1  - Scheller, Frieder W.
A1  - Viezzoli, Maria Silvia
A1  - Lisdat, Fred
T1  - Engineered superoxide dismutase monomers for superoxide biosensor applications
N2  - Because of its high reaction rate and specificity, the enzyme superoxide dismutase (SOD) offers great potential for the sensitive quantification of superoxide radicals in electrochemical biosensors. In this work, monomeric mutants of human Cu,Zn-SOD were engineered to contain one or two additional cysteine residues, which could be used to bind the protein to gold surfaces, thus making the use of promotor molecules unnecessary. Six mutants were successfully designed, expressed, and purified. All mutants bound directly to unmodified gold surfaces via the sulfur of the cysteine residues and showed a quasireversible, direct electron transfer to the electrode. Thermodynamic and kinetic parameters of the electron transfer were characterized and showed only slight variations between the individual mutants. For one of the mutants, the interaction with the superoxide radical was studied in more detail. For both partial reactions of the dismutation, an interaction between protein and radical could be shown. In an amperometric biosensorial approach, the SOD-mutant electrode was successfully applied for the detection of superoxide radicals. In the oxidation region, the electrode surpassed the sensitivity of the commonly used cytochrome c electrodes by similar to 1 order of magnitude while not being limited by interferences, but the electrode did not fully reach the sensitivity of dimeric Cu,Zn-SOD immobilized on MPA-modified gold
Y1  - 2006
UR  - http://pubs.acs.org/journal/ancham
U6  - https://doi.org/10.1021/Ac051465g
SN  - 0003-2700
ER  - 
TY  - JOUR
A1  - Wollenberger, Ursula
A1  - Lisdat, Fred
A1  - Scheller, Frieder W.
T1  - Enzymatic substrade recycling electrodes
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
A1  - Pfeiffer, Dorothea
A1  - Lisdat, Fred
A1  - Bauer, Christian G.
A1  - Gajovic, Nenad
T1  - Enzyme biosensors based on oxygen detection
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Büttemeyer, R.
A1  - Philipp, A. W
A1  - Schlenzka, L.
A1  - Mall, J. W.
A1  - Beissenhirtz, Moritz Karl
A1  - Lisdat, Fred
T1  - Epigallocatechin gallate can significantly decrease free oxygen radicals in the reperfusion insury in vivo
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Beissenhirtz, Moritz Karl
A1  - Scheller, Frieder W.
A1  - Lisdat, Fred
T1  - Immobilized cytochrome c sensor in organic / aqueous media for the characterization of hydrophilic and hydrophobic antioxidants
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Buttermeyer, R.
A1  - Philipp, A. W.
A1  - Mall, J. W.
A1  - Ge, Bixia
A1  - Scheller, Frieder W.
A1  - Lisdat, Fred
T1  - In vivo measurement of oxygen derived free radicals during reperfusion injury
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Wettstein, Christoph
A1  - Kano, Kenji
A1  - Schaefer, Daniel
A1  - Wollenberger, Ursula
A1  - Lisdat, Fred
T1  - Interaction of Flavin-Dependent Fructose Dehydrogenase with Cytochrome c as Basis for the Construction of Biomacromolecular Architectures on Electrodes
JF  - Analytical chemistry
N2  - The creation of electron transfer (ET) chains based on the defined arrangement of enzymes and redox proteins on electrode surfaces represents an interesting approach within the field of bioelectrocatalysis. In this study, we investigated the ET reaction of the flavin-dependent enzyme fructose dehydrogenase (FDH) with the redox protein cytochrome c (cyt c). Two different pH optima were found for the reaction in acidic and neutral solutions. When cyt c was adsorbed on an electrode surface while the enzyme remained in solution, ET proceeded efficiently in media of neutral pH. Interprotein ET was also observed in acidic media; however, it appeared to be less efficient. These findings suggest that two different ET pathways between the enzyme and cyt c may occur. Moreover, cyt c and FDH were immobilized in multiple layers on an electrode surface by means of another biomacromolecule: DNA (double stranded) using the layer -by -layer technique. The biprotein multilayer architecture showed a catalytic response in dependence on the fructose concentration, indicating that the ET reaction between both proteins is feasible even in the immobilized state. The electrode showed a defined response to fructose and a good storage stability. Our results contribute to the better understanding of the ET reaction between FDH and cyt c and provide the basis for the creation of all-biomolecule based fructose sensors the sensitivity of which can be controlled by the layer preparation.
Y1  - 2016
U6  - https://doi.org/10.1021/acs.analchem.6b00815
SN  - 0003-2700
SN  - 1520-6882
VL  - 88
SP  - 6382
EP  - 6389
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Sarauli, David
A1  - Borowski, Anja
A1  - Peters, Kristina
A1  - Schulz, Burkhard
A1  - Fattakhova-Rohlfing, Dina
A1  - Leimkühler, Silke
A1  - Lisdat, Fred
T1  - Investigation of the pH-Dependent Impact of Sulfonated Polyaniline on Bioelectrocatalytic Activity of Xanthine Dehydrogenase
JF  - ACS catalysis
N2  - We report on the pH-dependent bioelectrocatalytic activity of the redox enzyme xanthine dehydrogenase (XDH) in the presence of sulfonated polyaniline PMSA1 (poly(2-methoxyaniline-5-sulfonic acid)-co-aniline). Ultraviolet-visible (UV-vis) spectroscopic measurements with both components in solution reveal electron transfer from the hypoxanthine (HX)-reduced enzyme to the polymer. The enzyme shows bioelectrocatalytic activity on indium tin oxide (ITO) electrodes, when the polymer is present. Depending on solution pH, different processes can be identified. It can be demonstrated that not only product-based communication with the electrode but also efficient polymer-supported bioelectrocatalysis occur. Interestingly, substrate dependent catalytic currents can be obtained in acidic and neutral solutions, although the highest activity of XDH with natural reaction partners is in the alkaline region. Furthermore, operation of the enzyme electrode without addition of the natural cofactor of XDH is feasible. Finally, macroporous ITO electrodes have been used as an immobilization platform for the fabrication of HX-sensitive electrodes. The study shows that the efficient polymer/enzyme interaction can be advantageously combined with the open structure of an electrode material of controlled pore size, resulting in good processability, stability, and defined signal transfer in the presence of a substrate.
KW  - enzyme bioelectrocatalysis
KW  - sulfonated polyanilines
KW  - xanthine dehydrogenase
KW  - pH-dependent electrochemistry
KW  - macroporous ITO electrodes
Y1  - 2016
U6  - https://doi.org/10.1021/acscatal.6b02011
SN  - 2155-5435
VL  - 6
SP  - 7152
EP  - 7159
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Kröning, Steffen
A1  - Scheller, Frieder W.
A1  - Wollenberger, Ursula
A1  - Lisdat, Fred
T1  - Myoglobin-Clay Electrode for Nitric Oxide (NO) Detection in Solution
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Lisdat, Fred
A1  - Ge, Bixia
A1  - Krause, B.
A1  - Ehrlich, A.
A1  - Bienert, H.
A1  - Scheller, Frieder W.
T1  - Nucleic acid-promoted electron transfer to cytochrome c
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Lisdat, Fred
A1  - Ge, Bixia
A1  - Scheller, Frieder W.
T1  - Oligonucleotide-modified electrodes for fast electron transfer to cytochrome c
Y1  - 1999
ER  - 
TY  - JOUR
A1  - Krylov, Andrey. V.
A1  - Adamzig, H.
A1  - Walter, A. D.
A1  - Loechel, B.
A1  - Kurth, E.
A1  - Pulz, O.
A1  - Szeponik, Jan
A1  - Wegerich, Franziska
A1  - Lisdat, Fred
T1  - Parallel generation and detection of superoxide and hydrogen peroxide in a fluidic chip
JF  - Sensors and actuators : B, Chemical
N2  - A fluidic chip system was developed, which combines a stable generation of superoxide radicals and hydrogen peroxide with their sensorial detection. The generation of both reactive oxygen species was achieved by immobilization of xanthine oxidase on controlled pore glass in a reaction chamber. Antioxidants can be introduced into the fluidic chip system by means of mixing chamber. The detection of both species is based on the amperometric principle using a biosensor chip with two working electrodes. As sensing protein for both electrodes cytochrome c was used. The novel system was designed for the quantification of the antioxidant efficiency of different potential scavengers of the respective reactive species in an aqueous medium. Several model antioxidants such as ascorbic acid or catalase have been tested under flow conditions.
KW  - biosensor
KW  - cytochrome c
KW  - flow system
KW  - reactive oxygen species
KW  - antioxidant
Y1  - 2006
U6  - https://doi.org/10.1016/j.snb.2005.11.062
SN  - 0925-4005
VL  - 119
IS  - 1
SP  - 118
EP  - 126
PB  - Elsevier
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Lisdat, Fred
A1  - Scheller, Frieder W.
T1  - Principles of sensorial radical detection - a minireview
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Lisdat, Fred
A1  - Ho, Wah O.
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
A1  - Richter, Torsten
A1  - Bilitewski, Ursula
T1  - Recycling systems based on screen-printed electrodes
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
A1  - Wollenberger, Ursula
A1  - Warsinke, Axel
A1  - Lisdat, Fred
T1  - Research and development in biosensors
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Fandrich, Artur
A1  - Buller, Jens
A1  - Memczak, Henry
A1  - Stoecklein, W.
A1  - Hinrichs, K.
A1  - Wischerhoff, E.
A1  - Schulz, B.
A1  - Laschewsky, André
A1  - Lisdat, Fred
T1  - Responsive Polymer-Electrode Interface-Study of its Thermo- and pH-Sensitivity and the Influence of Peptide Coupling
JF  - Electrochimica acta : the journal of the International Society of Electrochemistry (ISE)
N2  - This study introduces a thermally responsive, polymer-based electrode system. The key component is a surface-attached, temperature-responsive poly(oligoethylene glycol) methacrylate (poly(OEGMA)) type polymer bearing photoreactive benzophenone and carboxy groups containing side chains. The responsive behavior of the polymer in aqueous media has been investigated by turbidimetry measurements. Polymer films are formed on gold substrates by means of the photoreactive 2(dicyclohexylphosphino)benzophenone (DPBP) through photocrosslinking. The electrochemical behavior of the resulting polymer-substrate interface has been investigated in buffered [Fe(CN)6](3-)/[Fe (CN)6](4-)solutions at room temperature and under temperature variation by cyclic voltammetry (CV). The CV experiments show that with increasing temperature structural changes of the polymer layer occur, which alter the output of the electrochemical measurement. Repeated heating/cooling cycles analyzed by CV measurements and pH changes analyzed by quartz crystal microbalance with dissipation monitoring (QCM-D) reveal the reversible nature of the restructuring process. The immobilized films are further modified by covalent coupling of two small biomolecules - a hydrophobic peptide and a more hydrophilic one. These attached components influence the hydrophobicity of the layer in a different way the resulting change of the temperature-caused behavior has been studied by CV indicating a different state of the polymer after coupling of the hydrophobic peptide.
KW  - Stimuli-responsive materials
KW  - electroanalysis
KW  - modified electrode
KW  - bioreceptors
KW  - peptides
KW  - surface modification
KW  - cyclic voltammetry
KW  - IR ellipsometry
KW  - quartz crystal microbalance
Y1  - 2017
U6  - https://doi.org/10.1016/j.electacta.2017.01.080
SN  - 0013-4686
SN  - 1873-3859
VL  - 229
SP  - 325
EP  - 333
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Lisdat, Fred
A1  - Dronov, Roman
A1  - Möhwald, Helmuth
A1  - Scheller, Frieder W.
A1  - Kurth, Dirk G.
T1  - Self-assembly of electro-active protein architectures on electrodes for the construction of biomimetic signal chains
N2  - The layer-by-layer adsorption technique based on the consecutive deposition of oppositely charged species is for the preparation of protein multilayers with fully electro-active protein molecules. The methodology was established with cytochrome c and the polyelectrolyte sulfonated polyaniline (PASA). The technique is also useful for the construction of bi-protein architectures confining protein-protein communication to an electrode. Following natural examples of protein complexes with defined signal transfer, cytochrome c was arranged with enzymes such as xanthine oxidase, bilirubin oxidase, laccase, and sulfite oxidase in self-assembled multilayer architectures. Thus, biomimetic signal chains from the enzyme substrate via the enzyme and cytochrome c towards the electrode can be established. Communication between proteins immobilised in multiple layers on the electrode can be achieved by in situ generation of small shuttle molecules or more advantageously by direct interprotein electron transfer. This allows the construction of new sensing electrodes, the properties of which can be tuned by the number of deposited protein layers. The mechanism of electron transfer within such protein assemblies on gold electrodes will be discussed.
Y1  - 2009
UR  - http://xlink.rsc.org/jumptojournal.cfm?journal_code=CC
U6  - https://doi.org/10.1039/B813559b
SN  - 1359-7345
ER  - 
TY  - JOUR
A1  - Sarauli, David
A1  - Riedel, Marc
A1  - Wettstein, Christoph
A1  - Hahn, Robert
A1  - Stiba, Konstanze
A1  - Wollenberger, Ursula
A1  - Leimkühler, Silke
A1  - Schmuki, Patrik
A1  - Lisdat, Fred
T1  - Semimetallic TiO2 nanotubes new interfaces for bioelectrochemical enzymatic catalysis
JF  - Journal of materials chemistry
N2  - Different self-organized TiO2 nanotube structures are shown to represent new interfaces for the achievement of bioelectrochemical enzymatic catalysis involving redox proteins and enzymes without further surface modification or the presence of mediators.
Y1  - 2012
U6  - https://doi.org/10.1039/c2jm16427b
SN  - 0959-9428
VL  - 22
IS  - 11
SP  - 4615
EP  - 4618
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  -