@article{WollenbergerDrungilieneStoeckleinetal.1996, author = {Wollenberger, Ursula and Drungiliene, A. and St{\"o}cklein, Walter F. M. and Kulys, J. and Scheller, Frieder W.}, title = {Direct electrocatalytic determination of dissolved peroxidases}, year = {1996}, language = {en} } @article{LoewWollenbergerSchelleretal.2009, author = {Loew, Noya and Wollenberger, Ursula and Scheller, Frieder W. and Katterle, Martin}, title = {Direct electrochemistry and spectroelectrochemistry of osmium substituted horseradish peroxidase}, issn = {1567-5394}, doi = {10.1016/j.bioelechem.2009.03.015}, year = {2009}, abstract = {In this contribution the substitution of the central protoporphyrin IX iron complex of horseradish peroxidase by the respective osmium porphyrin complex is described. The direct electrochemical reduction of the Os containing horseradish peroxidase (OsHRP) was achieved at ITO and modified glassy carbon electrodes and in combination with spectroscopy revealed the three redox couples (OsHRP)-H-III/(OsHRP)-H-IV, (OsHRP)-H-IV/(OsHRP)-H-V and (OsHRP)-H-V/ (OsHRP)-H-VI. The midpoint potentials differ dependent on the electrode material used with E-1/2 (Os-III/IV) of -0.4 V (ITO) and -0.25 V (GC), E-1/2 (Os-IV/V) of -0.16 V (ITO) and +0.10 V (GC), and E-1/2 (Os-V/VI)of +018 V (ITO), respectively Moreover, with immobilised OsHRP the direct electrocatalytic reduction of hydrogen peroxide and tert-butyl hydroperoxide was observed. In comparison to electrodes modified with native HRP the sensitivity of the OsHRP-electrode for tert-butyl hydroperoxide is higher.}, language = {en} } @article{TanneJeoungPengetal.2015, author = {Tanne, Johannes and Jeoung, Jae-Hun and Peng, Lei and Yarman, Aysu and Dietzel, Birgit and Schulz, Burkhard and Schad, Daniel and Dobbek, Holger and Wollenberger, Ursula and Bier, Frank Fabian and Scheller, Frieder W.}, title = {Direct Electron Transfer and Bioelectrocatalysis by a Hexameric, Heme Protein at Nanostructured Electrodes}, series = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis}, volume = {27}, journal = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis}, number = {10}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1040-0397}, doi = {10.1002/elan.201500231}, pages = {2262 -- 2267}, year = {2015}, abstract = {A nanohybrid consisting of poly(3-aminobenzenesulfonic acid-co-aniline) and multiwalled carbon nanotubes [MWCNT-P(ABS-A)]) on a gold electrode was used to immobilize the hexameric tyrosine-coordinated heme protein (HTHP). The enzyme showed direct electron transfer between the heme group of the protein and the nanostructured surface. Desorption of the noncovalently bound heme from the protein could be excluded by control measurements with adsorbed hemin on aminohexanthiol-modified electrodes. The nanostructuring and the optimised charge characteristics resulted in a higher protein coverage as compared with MUA/MU modified electrodes. The adsorbed enzyme shows catalytic activity for the cathodic H2O2 reduction and oxidation of NADH.}, language = {en} } @article{JinBernhardtStoeckleinetal.1998, author = {Jin, Wen and Bernhardt, Rita and St{\"o}cklein, Walter F. M. and Scheller, Frieder W.}, title = {Direct electron transfer of adrenodoxin-a [2Fe-2S] protein-- and its mutants on modified gold electrode}, year = {1998}, language = {en} } @article{WuWollenbergerHofrichteretal.2011, author = {Wu, Yunhua and Wollenberger, Ursula and Hofrichter, Martin and Ullrich, Rene and Scheibner, Katrin and Scheller, Frieder W.}, title = {Direct electron transfer of Agrocybe aegerita peroxygenase at electrodes modified with chitosan-capped Au nanoparticles and its bioelectrocatalysis to aniline}, series = {Sensors and actuators : B, Chemical}, volume = {160}, journal = {Sensors and actuators : B, Chemical}, number = {1}, publisher = {Elsevier}, address = {Lausanne}, issn = {0925-4005}, doi = {10.1016/j.snb.2011.09.090}, pages = {1419 -- 1426}, year = {2011}, abstract = {Three different sizes of chitosan-capped Au nanoparticles were synthesized and were used to incorporate Agrocybe aegerita peroxygenase (AaeAPO) onto the surface of glassy carbon electrode. The direct electron transfer of AaeAPO was achieved in all films. The highest amount of electroactive enzyme and highest electron transfer rate constant k(s) of AaeAPO were obtained in the film with the smallest size of chitosan-capped Au nanoparticles. In anaerobic solutions, quasi-reversible oxidation and reduction are obtained with a formal potential of -0.280V vs. Ag/AgCl 1 M KCl in 100 mM (pH 7.0) PBS at scan rate of 1 V s(-1). Bioelectrocatalytic reduction currents can be obtained with the AaeAPO-modified electrode on addition of hydrogen peroxide. This reaction was suppressed when sodium azide, an inhibitor of AaeAPO, was present. Furthermore, the peroxide-dependent conversion of aniline was characterized and it was found that a polymer product via p-aminophenol is formed. And the AaeAPO biosensor was applied to determine aniline and p-aminophenol.}, language = {en} } @article{ShumyantsevaIvanovBistolasetal.2004, author = {Shumyantseva, V. V. and Ivanov, Y. D. and Bistolas, Nikitas and Scheller, Frieder W. and Archakov, Alexander I. and Wollenberger, Ursula}, title = {Direct electron transfer of cytochrome P450 2B4 at electrodes modified with non-ionic detergent and colloidal clay nanoparticles}, year = {2004}, abstract = {A method for construction of biosensors with membranous cytochrome P450 isoenzymes was developed based on clay/ detergent/protein mixed films. Thin films of sodium montmorillonite colloid with incorporated cytochrome P450 2134 (CYP2B4) with nonionic detergent were prepared on glassy carbon electrodes. The modified electrodes were electrochemically characterized, and bio-electrocatalytic reactions were followed. CYP2B4 can be reduced fast on clay- modified glassy carbon electrodes in the presence of the nonionic detergent Tween 80. In anaerobic solutions, reversible oxidation and reduction is obtained with a formal potential between -0.292 and - 0.305 V vs Ag/AgCl 1 M KCl depending on the preparation of the biosensor. In air-saturated solution, bio-electrocatalytic reduction currents can be obtained with the CYP2B4-modified electrode on addition of typical substrates such as aminopyrine and benzphetamine. This reaction was suppressed when methyrapone, an inhibitor of P450 reactions, was present. Measurement of product formation also indicates the bioelectrocatialysis by CYP2B4}, language = {en} } @article{PaeschkeHintscheWollenbergeretal.1995, author = {Paeschke, Manfred and Hintsche, Rainer and Wollenberger, Ursula and Jin, Wen and Scheller, Frieder W.}, title = {Dynamic redox recycling of cytochrome c}, issn = {0022-0728}, year = {1995}, language = {en} } @article{StoeckleinSchellerAbuknesha1995, author = {St{\"o}cklein, Walter F. M. and Scheller, Frieder W. and Abuknesha, Rhamadan}, title = {Effects of organic solvents on semicontinuous immunochemical detection of coumarin derivatives}, year = {1995}, language = {en} } @article{MakowerBarminScheller2000, author = {Makower, Alexander and Barmin, Anatoli V. and Scheller, Frieder W.}, title = {Eine neue Methode zur hochempfindlichen Analyse von Pestiziden}, year = {2000}, language = {de} } @article{StoeckleinScheller1995, author = {St{\"o}cklein, Walter F. M. and Scheller, Frieder W.}, title = {Einsatz von Enzymen und Antik{\"o}rpern in organischen L{\"o}sungsmitteln}, year = {1995}, language = {de} } @article{BeissenhirtzSchellerStoeckleinetal.2004, author = {Beissenhirtz, Moritz Karl and Scheller, Frieder W. and St{\"o}cklein, Walter F. M. and Kurth, D. and M{\"o}hwald, Helmuth and Lisdat, Fred}, title = {Electroactive cytochrome c multilayers within a polyelectrolyte assembly}, year = {2004}, language = {en} } @article{KulysDrungilieneWollenbergeretal.1997, author = {Kulys, J. and Drungiliene, A. and Wollenberger, Ursula and Krikstopaitis, K. and Scheller, Frieder W.}, title = {Electroanalytical determination of peroxidases and laccases on carbon paste electrodes}, year = {1997}, language = {en} } @misc{SpricigoDronovLisdatetal.2009, author = {Spricigo, Roberto and Dronov, Roman and Lisdat, Fred and Leimk{\"u}hler, Silke and Scheller, Frieder W. and Wollenberger, Ursula}, title = {Electrocatalytic sulfite biosensor with human sulfite oxidase co-immobilized with cytochrome c in a polyelectrolyte-containing multilayer}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {945}, issn = {1866-8372}, doi = {10.25932/publishup-43117}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431176}, pages = {225 -- 233}, year = {2009}, abstract = {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.}, language = {en} } @article{SpricigoDronovLisdatetal.2009, author = {Spricigo, Roberto and Dronov, Roman and Lisdat, Fred and Leimk{\"u}hler, Silke and Scheller, Frieder W. and Wollenberger, Ursula}, title = {Electrocatalytic sulfite biosensor with human sulfite oxidase co-immobilized with cytochrome c in a polyelectrolyte-containing multilayer}, issn = {1618-2642}, doi = {10.1007/s00216-008-2432-y}, year = {2009}, abstract = {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.}, language = {en} } @article{KappBeissenhirtzGeyeretal.2006, author = {Kapp, Andreas and Beissenhirtz, Moritz Karl and Geyer, F. and Scheller, Frieder W. and Viezzoli, Maria Silvia and Lisdat, Fred}, title = {Electrochemical and sensorial behaviour of SOD mutants immobilized on gold electrodes in aqueous / organic solvent mixtures}, issn = {1040-0397}, doi = {10.1002/elan.200603620}, year = {2006}, language = {en} } @article{LisdatGeStoeckleinetal.2000, author = {Lisdat, Fred and Ge, Bixia and St{\"o}cklein, Walter F. M. and Scheller, Frieder W. and Meyer, T.}, title = {Electrochemical behaviour and nitric oxides interaction of immobilised cytochrome c from Rhodocyclus gelatinosus}, year = {2000}, language = {en} } @article{MakCheungTrauetal.2005, author = {Mak, Wing Cheung and Cheung, Kwan Yee and Trau, Dieter and Warsinke, Axel and Scheller, Frieder W. and Renneberg, Reinhard}, title = {Electrochemical bioassay utilizing encapsulated electrochemical active microcrystal biolabels}, issn = {0003-2700}, year = {2005}, abstract = {A new approach to perform electrochemical immunoassay based on the utilization of encapsulated microcrystal was developed. The microcrystal labels create a "supernova effect" upon exposure to a desired releasing agent. The microcrystal cores dissolve, and large amounts of signal-generating molecules diffuse across the capsule wall into the outer environment. Layer-by-Layer (LbL) technology was employed for the encapsulation of electrochemical signal- generating microcrystals (ferrocene microcrystals). The encapsulated microcrystals were conjugated with antibody molecules through the adsorption process. The biofunctionalized microcrystals were utilized as a probe for immunoassays. The microcrystal-based label system provided a high-signal molecule to antibody (SIP) ratio of 10(4)-10(5). Microcrystal biolabels with different antibody surface coverage (1.60-5.05 mg m(-2)) were subjected to a solid-phase immunoassay for the detection of mouse immunoglobulin G (M-IgG) molecules. The microcrystal-based immunoassay for the detection of M-IgG performed with microcrystals having antibody surface coverage of 5.05 mg m(-2) showed a sensitivity of 3.93 nA g(- 1) L-1 with a detection limit of 2.82 g L-1}, language = {en} } @article{ChenStoeckleinSchelleretal.2003, author = {Chen, Jian and St{\"o}cklein, Walter F. M. and Scheller, Frieder W. and Wollenberger, Ursula}, title = {Electrochemical determination of human hemoglobin by using ferrocene carboxylic acid modified carbon powder microelectrode}, year = {2003}, language = {en} } @article{DechtriratGajovicEichelmannWojciketal.2014, author = {Dechtrirat, Decha and Gajovic-Eichelmann, Nenad and Wojcik, Felix and Hartmann, Laura and Bier, Frank Fabian and Scheller, Frieder W.}, title = {Electrochemical displacement sensor based on ferrocene boronic acid tracer and immobilized glycan for saccharide binding proteins and E. coli}, series = {Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics}, volume = {58}, journal = {Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics}, publisher = {Elsevier}, address = {Oxford}, issn = {0956-5663}, doi = {10.1016/j.bios.2014.02.028}, pages = {1 -- 8}, year = {2014}, abstract = {Pathogens such as viruses and bacteria use their envelope proteins and their adhesin lectins to recognize the glycan residues presented on the cell surface of the target tissues. This principle of recognition is used in a new electrochemical displacement sensor for the protein concanavalin A (ConA). A gold electrode was first modified with a self-assembled monolayer of a thiolated mannose/OEG conjugate and a ferrocene boroxol derivative was pre-assembled as reporter molecule onto the mannose surface. The novel tracer molecule based on a 2-hydroxymethyl phenyl boronic acid derivative binds even at neutral pH to the saccharides which could expand the application towards biological samples (i.e., urine and feces). Upon the binding of ConA, the tracer was displaced and washed away from the sensor surface leading to a decrease in the electrochemical signal. Using square wave voltammetry (SWV), the concentration of ConA in the sample solution could be determined in the dynamic concentration range established from 38 nmol L-1 to 5.76 mu mol L-1 with a reproducible detection limit of 1 mu g mL(-1) (38 nmol L-1) based on the signal-to-noise ratio (S/N=3) with fast response of 15 min. The new reporter molecule showed a reduced non-specific displacement by BSA and ribonuclease A. The sensor was also successfully transferred to the first proof of principle for the detection of Escherichia coli exhibiting a detection limit of approximately 6 x 102 cells/mL Specificity of the displacement by target protein ConA and E. coli was demonstrated since the control proteins (i.e., BSA and RNaseA) and the control E. coli strain, which lack of type 1 fimbriae, were ineffective. (C) 2014 Elsevier B.V. All rights reserved.}, language = {en} } @article{WarsinkeBenkertScheller2000, author = {Warsinke, Axel and Benkert, Alexander and Scheller, Frieder W.}, title = {Electrochemical immunoassays}, year = {2000}, language = {en} } @article{FridmanWollenbergerBogdanovskayaetal.2000, author = {Fridman, Vadim and Wollenberger, Ursula and Bogdanovskaya, V. A. and Lisdat, Fred and Ruzgas, T. and Lindgren, A. and Gorton, Lo and Scheller, Frieder W.}, title = {Electrochemical investigation of cellobiose oxidation by cellobiose dehydrogenase in the presence of cytochrome c as mediator}, year = {2000}, language = {en} } @article{JinWollenbergerKaergeletal.1997, author = {Jin, Wen and Wollenberger, Ursula and K{\"a}rgel, E. and Schunck, W.-H. and Scheller, Frieder W.}, title = {Electrochemical investigation of the intermolecular electron transfer between cytochrome c and NADPH-cytochrome P450-reductase}, year = {1997}, language = {en} } @article{OzcelikayKurbanogluZhangetal.2019, author = {Ozcelikay, Goksu and Kurbanoglu, Sevinc and Zhang, Xiaorong and S{\"o}z, {\c{C}}ağla Kosak and Wollenberger, Ulla and Ozkan, Sibel A. and Yarman, Aysu and Scheller, Frieder W.}, title = {Electrochemical MIP Sensor for Butyrylcholinesterase}, series = {Polymers}, volume = {11}, journal = {Polymers}, number = {12}, publisher = {MDPI}, address = {Basel}, issn = {2073-4360}, doi = {10.3390/polym11121970}, pages = {11}, year = {2019}, abstract = {Molecularly imprinted polymers (MIPs) mimic the binding sites of antibodies by substituting the amino acid-scaffold of proteins by synthetic polymers. In this work, the first MIP for the recognition of the diagnostically relevant enzyme butyrylcholinesterase (BuChE) is presented. The MIP was prepared using electropolymerization of the functional monomer o-phenylenediamine and was deposited as a thin film on a glassy carbon electrode by oxidative potentiodynamic polymerization. Rebinding and removal of the template were detected by cyclic voltammetry using ferricyanide as a redox marker. Furthermore, the enzymatic activity of BuChE rebound to the MIP was measured via the anodic oxidation of thiocholine, the reaction product of butyrylthiocholine. The response was linear between 50 pM and 2 nM concentrations of BuChE with a detection limit of 14.7 pM. In addition to the high sensitivity for BuChE, the sensor responded towards pseudo-irreversible inhibitors in the lower mM range.}, language = {en} } @misc{OzcelikayKurbanogluZhangetal.2019, author = {Ozcelikay, Goksu and Kurbanoglu, Sevinc and Zhang, Xiaorong and S{\"o}z, {\c{C}}ağla Kosak and Wollenberger, Ulla and Ozkan, Sibel A. and Yarman, Aysu and Scheller, Frieder W.}, title = {Electrochemical MIP Sensor for Butyrylcholinesterase}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1138}, issn = {1866-8372}, doi = {10.25932/publishup-50185}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-501854}, pages = {13}, year = {2019}, abstract = {Molecularly imprinted polymers (MIPs) mimic the binding sites of antibodies by substituting the amino acid-scaffold of proteins by synthetic polymers. In this work, the first MIP for the recognition of the diagnostically relevant enzyme butyrylcholinesterase (BuChE) is presented. The MIP was prepared using electropolymerization of the functional monomer o-phenylenediamine and was deposited as a thin film on a glassy carbon electrode by oxidative potentiodynamic polymerization. Rebinding and removal of the template were detected by cyclic voltammetry using ferricyanide as a redox marker. Furthermore, the enzymatic activity of BuChE rebound to the MIP was measured via the anodic oxidation of thiocholine, the reaction product of butyrylthiocholine. The response was linear between 50 pM and 2 nM concentrations of BuChE with a detection limit of 14.7 pM. In addition to the high sensitivity for BuChE, the sensor responded towards pseudo-irreversible inhibitors in the lower mM range.}, language = {en} } @misc{YarmanKurbanogluJetzschmannetal.2018, author = {Yarman, Aysu and Kurbanoglu, Sevinc and Jetzschmann, Katharina J. and Ozkan, Sibel A. and Wollenberger, Ulla and Scheller, Frieder W.}, title = {Electrochemical MIP-Sensors for Drugs}, series = {Current Medicinal Chemistry}, volume = {25}, journal = {Current Medicinal Chemistry}, number = {33}, publisher = {Bentham Science Publishers LTD}, address = {Sharjah}, issn = {0929-8673}, doi = {10.2174/0929867324666171005103712}, pages = {4007 -- 4019}, year = {2018}, abstract = {In order to replace bio-macromolecules by stable synthetic materials in separation techniques and bioanalysis biomimetic receptors and catalysts have been developed: Functional monomers are polymerized together with the target analyte and after template removal cavities are formed in the "molecularly imprinted polymer" (MIP) which resemble the active sites of antibodies and enzymes. Starting almost 80 years ago, around 1,100 papers on MIPs were published in 2016. Electropolymerization allows to deposit MIPs directly on voltammetric electrodes or chips for quartz crystal microbalance (QCM) and surface plasmon resonance (SPR). For the readout of MIPs for drugs amperometry, differential pulse voltammetry (DPV) and impedance spectroscopy (EIS) offer higher sensitivity as compared with QCM or SPR. Application of simple electrochemical devices allows both the reproducible preparation of MIP sensors, but also the sensitive signal generation. Electrochemical MIP-sensors for the whole arsenal of drugs, e.g. the most frequently used analgesics, antibiotics and anticancer drugs have been presented in literature and tested under laboratory conditions. These biomimetic sensors typically have measuring ranges covering the lower nano-up to millimolar concentration range and they are stable under extreme pH and in organic solvents like nonaqueous extracts.}, language = {en} } @article{KulysKrikstopaitisSchelleretal.2004, author = {Kulys, J. and Krikstopaitis, K. and Scheller, Frieder W. and Wollenberger, Ursula}, title = {Electrochemical parameters of phenoxazine derivatives in solution and at monolayer-modified gold electrodes}, year = {2004}, abstract = {Electrochemical properties of beta-(10-phenoxazinyl) propylamine (APPX) and beta-(10-phenoxazinyl) propionic acid (PPX) have been studied in solution, and in immobilized state on gold electrodes modified with monolayers of cystamine and mercaptoundecanoic acid. A reversible diffusion-controlled process of APPX and PPX was observed at a bare gold electrode. The electrochemical conversion of both compounds at modified gold electrodes was a quasireversible diffusion-controlled process. The redox potential of immobilized APPX (443 mV) was similar to the potential in solution, while the value of the immobilized PPX was 131 mV higher than in solution. The immobilized mediators were electrocatalytically active in the fungal peroxidase-catalyzed hydrogen peroxide reduction}, language = {en} } @article{WelzelKossmehlEngelmannetal.1997, author = {Welzel, H.-P. and Kossmehl, G. and Engelmann, G. and Neumann, B. and Wollenberger, Ursula and Scheller, Frieder W.}, title = {Electrochemical polymerization of functionalized thiohene derivatives for immobilization of proteins}, year = {1997}, language = {en} } @article{PfeifferSchubertWollenbergeretal.1996, author = {Pfeiffer, Dorothea and Schubert, Frank and Wollenberger, Ursula and Scheller, Frieder W.}, title = {Electrochemical sensors : enzyme electrodes and field effect transistors}, year = {1996}, language = {en} } @article{JuLiuGeetal.2000, author = {Ju, Huangxian and Liu, Songqin and Ge, Bixia and Lisdat, Fred and Scheller, Frieder W.}, title = {Electrochemistry of cytochrome c immobilized on colloidal gold modified carbon paste electrodes and its electrocatalytic activity}, year = {2000}, language = {en} } @article{KatterleWollenbergerScheller1997, author = {Katterle, Martin and Wollenberger, Ursula and Scheller, Frieder W.}, title = {Electrochemistry of hemoglobin at modified silver electrodes is not a redox-process of iron protoporhyrin IX}, year = {1997}, language = {en} } @article{GeSchellerLisdat2003, author = {Ge, Bixia and Scheller, Frieder W. and Lisdat, Fred}, title = {Electrochemistry of immobilized CuZnSOD and FeSOD and their interaction with superoxide radicals}, year = {2003}, abstract = {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 {\~n} 4 mV and -154 {\~n} 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.}, language = {en} } @article{LeiWollenbergerBistolasetal.2002, author = {Lei, Chenghong and Wollenberger, Ursula and Bistolas, Nikitas and Guiseppi-Eli, A. and Scheller, Frieder W.}, title = {Electron transfer of hemoglobin at electrodes modified with colloidal clay nanoparticles}, year = {2002}, language = {en} } @article{ZhangYarmanErdossyetal.2018, author = {Zhang, Xiaorong and Yarman, Aysu and Erdossy, Julia and Katz, Sagie and Zebger, Ingo and Jetzschmann, Katharina J. and Altintas, Zeynep and Wollenberger, Ulla and Gyurcsanyi, Robert E. and Scheller, Frieder W.}, title = {Electrosynthesized MIPs for transferrin}, series = {Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics}, volume = {105}, journal = {Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics}, publisher = {Elsevier}, address = {Oxford}, issn = {0956-5663}, doi = {10.1016/j.bios.2018.01.011}, pages = {29 -- 35}, year = {2018}, abstract = {Molecularly imprinted polymer (MP) nanofilrns for transferrin (Trf) have been synthesized on gold surfaces by electro-polymerizing the functional monomer scopoletin in the presence of the protein target or around pre-adsorbed Trf. As determined by atomic force microscopy (AFM) the film thickness was comparable with the molecular dimension of the target. The target (re)binding properties of the electro-synthesized MIP films was evaluated by cyclic voltammetry (CV) and square wave voltammetry (SWV) through the target-binding induced permeability changes of the MIP nanofilms to the ferricyanide redox marker, as well as by surface plasmon resonance (SPR) and surface enhanced infrared absorption spectroscopy (SEIRAS) of the immobilized protein molecules. For Trf a linear concentration dependence in the lower micromolar range and an imprinting factor of similar to 5 was obtained by SWV and SPR. Furthermore, non-target proteins including the iron-free apo-Trf were discriminated by pronounced size and shape specificity. Whilst it is generally assumed that the rebinding of the target or of cross-reacting proteins exclusively takes place at the polymer here we considered also the interaction of the protein molecules with the underlying gold transducers. We demonstrate by SWV that adsorption of proteins suppresses the signal of the redox marker even at the bare gold surface and by SEIRAS that the treatment of the MIP with proteinase K or NaOH only partially removes the target protein. Therefore, we conclude that when interpreting binding of proteins to directly MIP-covered gold electrodes the interactions between the protein and the gold surface should also be considered.}, language = {en} } @misc{ErdossyHorvathYarmanetal.2016, author = {Erdossy, Julia and Horvath, Viola and Yarman, Aysu and Scheller, Frieder W. and Gyurcsanyi, Robert E.}, title = {Electrosynthesized molecularly imprinted polymers for protein recognition}, series = {Trends in Analytical Chemistry}, volume = {79}, journal = {Trends in Analytical Chemistry}, publisher = {Elsevier}, address = {Oxford}, issn = {0165-9936}, doi = {10.1016/j.trac.2015.12.018}, pages = {179 -- 190}, year = {2016}, abstract = {Molecularly imprinted polymers (MIPs) for the recognition of proteins are expected to possess high affinity through the establishment of multiple interactions between the polymer matrix and the large number of functional groups of the target. However, while highly affine recognition sites need building blocks rich in complementary functionalities to their target, such units are likely to generate high levels of nonspecific binding. This paradox, that nature solved by evolution for biological receptors, needs to be addressed by the implementation of new concepts in molecular imprinting of proteins. Additionally, the structural variability, large size and incompatibility with a range of monomers made the development of protein MIPs to take a slow start. While the majority of MIP preparation methods are variants of chemical polymerization, the polymerization of electroactive functional monomers emerged as a particularly advantageous approach for chemical sensing application. Electropolymerization can be performed from aqueous solutions to preserve the natural conformation of the protein templates, with high spatial resolution and electrochemical control of the polymerization process. This review compiles the latest results, identifying major trends and providing an outlook on the perspectives of electrosynthesised protein-imprinted MIPs for chemical sensing. (C) 2016 Elsevier B.V. All rights reserved.}, language = {en} } @article{StojanovicErdossyKeltaietal.2017, author = {Stojanovic, Zorica and Erdossy, Julia and Keltai, Katalin and Scheller, Frieder W. and Gyurcsanyi, Robert E.}, title = {Electrosynthesized molecularly imprinted polyscopoletin nanofilms for human serum albumin detection}, series = {Analytica chimica acta : an international journal devoted to all branches of analytical chemistry}, volume = {977}, journal = {Analytica chimica acta : an international journal devoted to all branches of analytical chemistry}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0003-2670}, doi = {10.1016/j.aca.2017.04.043}, pages = {1 -- 9}, year = {2017}, abstract = {Molecularly imprinted polymers (MIPs) rendered selective solely by the imprinting with protein templates lacking of distinctive properties to facilitate strong target-MIP interaction are likely to exhibit medium to low template binding affinities. While this prohibits the use of such MIPs for applications requiring the assessment of very low template concentrations, their implementation for the quantification of high-abundance proteins seems to have a clear niche in the analytical practice. We investigated this opportunity by developing a polyscopoletin-based MIP nanofilm for the electrochemical determination of elevated human serum albumin (HSA) in urine. As reference for a low abundance protein ferritin-MIPs were also prepared by the same procedure. Under optimal conditions, the imprinted sensors gave a linear response to HSA in the concentration range of 20-100 mg/dm(3), and to ferritin in the range of 120-360 mg/dm(3). While as expected the obtained limit of detection was not sufficient to determine endogenous ferritin in plasma, the HSA-sensor was successfully employed to analyse urine samples of patients with albuminuria. The results suggest that MIP-based sensors may be applicable for quantifying high abundance proteins in a clinical setting. (c) 2017 Elsevier B.V. All rights reserved.}, language = {en} } @article{WollenbergerBistolasJungetal.2004, author = {Wollenberger, Ursula and Bistolas, Nikitas and Jung, Christiane and Shumyantseva, V. V. and Ruzgas, T. and Scheller, Frieder W.}, title = {Elektroden-Design f{\"u}r elektronische Wechselwirkung mit Monooxygenasen}, isbn = {3-8047-2132-x}, year = {2004}, language = {de} } @article{KirsteinKirsteinSchelleretal.1994, author = {Kirstein, Dieter and Kirstein, Lincoln and Scheller, Frieder W. and Dieckmann, St. and Ronnenberg, J. and Beckmann, Dieter and Weckenbrock, E.}, title = {Elektroenzymatische Reduktion von Nitrat}, year = {1994}, language = {de} } @article{BeissenhirtzSchellerViezzolietal.2006, author = {Beissenhirtz, Moritz Karl and Scheller, Frieder W. and Viezzoli, Maria Silvia and Lisdat, Fred}, title = {Engineered superoxide dismutase monomers for superoxide biosensor applications}, issn = {0003-2700}, doi = {10.1021/Ac051465g}, year = {2006}, abstract = {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}, language = {en} } @article{NeumannGoetzWrzoleketal.2018, author = {Neumann, Bettina and G{\"o}tz, Robert and Wrzolek, Pierre and Scheller, Frieder W. and Weidinger, Inez M. and Schwalbe, Matthias and Wollenberger, Ulla}, title = {Enhancement of the Electrocatalytic Activity of Thienyl-Substituted Iron Porphyrin Electropolymers by a Hangman Effect}, series = {ChemCatChem : heterogeneous \& homogeneous \& bio- \& nano-catalysis ; a journal of ChemPubSoc Europe}, volume = {10}, journal = {ChemCatChem : heterogeneous \& homogeneous \& bio- \& nano-catalysis ; a journal of ChemPubSoc Europe}, number = {19}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1867-3880}, doi = {10.1002/cctc.201800934}, pages = {4353 -- 4361}, year = {2018}, abstract = {The thiophene-modified iron porphyrin FeT3ThP and the respective iron Hangman porphyrin FeH3ThP, incorporating a carboxylic acid hanging group in the second coordination sphere of the iron center, were electropolymerized on glassy carbon electrodes using 3,4-ethylenedioxythiophene (EDOT) as co-monomer. Scanning electron microscopy images and Resonance Raman spectra demonstrated incorporation of the porphyrin monomers into a fibrous polymer network. Porphyrin/polyEDOT films catalyzed the reduction of molecular oxygen in a four-electron reaction to water with onset potentials as high as +0.14V vs. Ag/AgCl in an aqueous solution of pH7. Further, FeT3ThP/polyEDOT films showed electrocatalytic activity towards reduction of hydrogen peroxide at highly positive potentials, which was significantly enhanced by introduction of the carboxylic acid hanging group in FeH3ThP. The second coordination sphere residue promotes formation of a highly oxidizing reaction intermediate, presumably via advantageous proton supply, as observed for peroxidases and catalases making FeH3ThP/polyEDOT films efficient mimics of heme enzymes.}, language = {en} } @article{WollenbergerSchubertPfeifferetal.1993, author = {Wollenberger, Ursula and Schubert, Florian and Pfeiffer, Dorothea and Scheller, Frieder W.}, title = {Enhancing biosensor performance using multienzyme systems}, year = {1993}, language = {en} } @article{WollenbergerLisdatScheller1997, author = {Wollenberger, Ursula and Lisdat, Fred and Scheller, Frieder W.}, title = {Enzymatic substrade recycling electrodes}, year = {1997}, language = {en} } @article{SchellerPfeifferSchubertetal.1995, author = {Scheller, Frieder W. and Pfeiffer, Dorothea and Schubert, Florian and Wollenberger, Ursula}, title = {Enzyme - based electrodes}, year = {1995}, language = {en} } @article{WollenbergerScheller1993, author = {Wollenberger, Ursula and Scheller, Frieder W.}, title = {Enzyme activation for activator and enzyme activity measurement}, year = {1993}, language = {en} } @article{WollenbergerNeumannScheller1993, author = {Wollenberger, Ursula and Neumann, B. and Scheller, Frieder W.}, title = {Enzyme and microbial sensors for environmental Monitoring}, year = {1993}, language = {en} } @article{WollenbergerNeumannRiedeletal.1994, author = {Wollenberger, Ursula and Neumann, B. and Riedel, K. and Scheller, Frieder W.}, title = {Enzyme and microbial sensors for phosphate, phenols, pesticides and peroxides}, year = {1994}, language = {en} } @article{SchellerPfeifferLisdatetal.1998, author = {Scheller, Frieder W. and Pfeiffer, Dorothea and Lisdat, Fred and Bauer, Christian G. and Gajovic, Nenad}, title = {Enzyme biosensors based on oxygen detection}, year = {1998}, language = {en} } @article{YarmanBadalyanGajovicEichelmannetal.2011, author = {Yarman, Aysu and Badalyan, Artavazd and Gajovic-Eichelmann, Nenad and Wollenberger, Ursula and Scheller, Frieder W.}, title = {Enzyme electrode for aromatic compounds exploiting the catalytic activities of microperoxidase-11}, series = {Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics}, volume = {30}, journal = {Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics}, number = {1}, publisher = {Elsevier}, address = {Oxford}, issn = {0956-5663}, doi = {10.1016/j.bios.2011.09.004}, pages = {320 -- 323}, year = {2011}, abstract = {Microperoxidase-11 (MR-11) which has been immobilised in a matrix of chitosan-embedded gold nanoparticles on the surface of a glassy carbon electrode catalyzes the conversion of aromatic substances. This peroxide-dependent catalysis of microperoxidase has been applied in an enzyme electrode for the first time to indicate aromatic compounds such as aniline. 4-fluoroaniline, catechol and p-aminophenol. The electrode signal is generated by the cathodic reduction of the quinone or quinoneimine which is formed in the presence of both MP-II and peroxide from the substrate. The same sensor principle will be extended to aromatic drugs.}, language = {en} } @article{SchellerWollenberger2003, author = {Scheller, Frieder W. and Wollenberger, Ursula}, title = {Enzyme Electrodes}, isbn = {3-527-30401-0}, year = {2003}, language = {en} } @article{StoeckleinBehrsingScharteetal.2000, author = {St{\"o}cklein, Walter F. M. and Behrsing, Olaf and Scharte, Gudrun and Micheel, Burkhard and Benkert, Alexander and Sch{\"o}ssler, W. and Warsinke, Axel and Scheller, Frieder W.}, title = {Enzyme kinetic assays with surface plasmon resonance (BIAcore) based on competition between enzyme and creatinine antibody}, year = {2000}, language = {en} } @article{StoeckleinMakowerBieretal.1997, author = {St{\"o}cklein, Walter F. M. and Makower, Alexander and Bier, Frank Fabian and Scheller, Frieder W.}, title = {Enzyme sensors and enzyme amplifification systems}, year = {1997}, language = {en} }