TY - JOUR A1 - Caserta, Giorgio A1 - Zhang, Xiaorong A1 - Yarman, Aysu A1 - Supala, Eszter A1 - Wollenberger, Ulla A1 - Gyurcsányi, Róbert E. A1 - Zebger, Ingo A1 - Scheller, Frieder W. T1 - Insights in electrosynthesis, target binding, and stability of peptide-imprinted polymer nanofilms JF - Electrochimica acta : the journal of the International Society of Electrochemistry (ISE) N2 - Molecularly imprinted polymer (MIP) nanofilms have been successfully implemented for the recognition of different target molecules: however, the underlying mechanistic details remained vague. This paper provides new insights in the preparation and binding mechanism of electrosynthesized peptide-imprinted polymer nanofilms for selective recognition of the terminal pentapeptides of the beta-chains of human adult hemoglobin, HbA, and its glycated form HbA1c. To differentiate between peptides differing solely in a glucose adduct MIP nanofilms were prepared by a two-step hierarchical electrosynthesis that involves first the chemisorption of a cysteinyl derivative of the pentapeptide followed by electropolymerization of scopoletin. This approach was compared with a random single-step electrosynthesis using scopo-letin/pentapeptide mixtures. Electrochemical monitoring of the peptide binding to the MIP nanofilms by means of redox probe gating revealed a superior affinity of the hierarchical approach with a Kd value of 64.6 nM towards the related target. Changes in the electrosynthesized non-imprinted polymer and MIP nanofilms during chemical, electrochemical template removal and rebinding were substantiated in situ by monitoring the characteristic bands of both target peptides and polymer with surface enhanced infrared absorption spectroscopy. This rational approach led to MIPs with excellent selectivity and provided key mechanistic insights with respect to electrosynthesis, rebinding and stability of the formed MIPs. KW - SEIRA spectroelectrochemistry KW - peptide imprinting KW - electrosynthesis KW - MIP KW - glycated peptide Y1 - 2021 U6 - https://doi.org/10.1016/j.electacta.2021.138236 SN - 0013-4686 SN - 1873-3859 VL - 381 PB - Elsevier CY - New York, NY [u.a.] 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 - Bosserdt, Maria A1 - Gajovic-Eichelman, Nenad A1 - Scheller, Frieder W. T1 - Modulation of direct electron transfer of cytochrome c by use of a molecularly imprinted thin film JF - Analytical & bioanalytical chemistry N2 - We describe the preparation of a molecularly imprinted polymer film (MIP) on top of a self-assembled monolayer (SAM) of mercaptoundecanoic acid (MUA) on gold, where the template cytochrome c (cyt c) participates in direct electron transfer (DET) with the underlying electrode. To enable DET, a non-conductive polymer film is electrodeposited from an aqueous solution of scopoletin and cyt c on to the surface of a gold electrode previously modified with MUA. The electroactive surface concentration of cyt c was 0.5 pmol cm(-2). In the absence of the MUA layer, no cyt c DET was observed and the pseudo-peroxidatic activity of the scopoletin-entrapped protein, assessed via oxidation of Ampliflu red in the presence of hydrogen peroxide, was only 30 % of that for the MIP on MUA. This result indicates that electrostatic adsorption of cyt c by the MUA-SAM substantially increases the surface concentration of cyt c during the electrodeposition step, and is a prerequisite for the productive orientation required for DET. After template removal by treatment with sulfuric acid, rebinding of cyt c to the MUA-MIP-modified electrode occurred with an affinity constant of 100,000 mol(-1) L, a value three times higher than that determined by use of fluorescence titration for the interaction between scopoletin and cyt c in solution. The DET of cyt c in the presence of myoglobin, lysozyme, and bovine serum albumin (BSA) reveals that the MIP layer suppresses the effect of competing proteins. KW - Cytochrome c KW - Molecularly imprinted polymer film KW - Mercaptoundecanoic acid KW - Direct electron transfer KW - Scopoletin (7-hydroxy-6-methoxycoumarin) Y1 - 2013 U6 - https://doi.org/10.1007/s00216-013-7009-8 SN - 1618-2642 VL - 405 IS - 20 SP - 6437 EP - 6444 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Bognár, Zsófia A1 - Supala, Eszter A1 - Yarman, Aysu A1 - Zhang, Xiaorong A1 - Bier, Frank Fabian A1 - Scheller, Frieder W. A1 - Gyurcsanyi, Róbert E. T1 - Peptide epitope-imprinted polymer microarrays for selective protein recognition BT - application for SARS-CoV-2 RBD protein JF - Chemical science / RSC, Royal Society of Chemistry N2 - We introduce a practically generic approach for the generation of epitope-imprinted polymer-based microarrays for protein recognition on surface plasmon resonance imaging (SPRi) chips. The SPRi platform allows the subsequent rapid screening of target binding kinetics in a multiplexed and label-free manner. The versatility of such microarrays, both as synthetic and screening platform, is demonstrated through developing highly affine molecularly imprinted polymers (MIPs) for the recognition of the receptor binding domain (RBD) of SARS-CoV-2 spike protein. A characteristic nonapeptide GFNCYFPLQ from the RBD and other control peptides were microspotted onto gold SPRi chips followed by the electrosynthesis of a polyscopoletin nanofilm to generate in one step MIP arrays. A single chip screening of essential synthesis parameters, including the surface density of the template peptide and its sequence led to MIPs with dissociation constants (K-D) in the lower nanomolar range for RBD, which exceeds the affinity of RBD for its natural target, angiotensin-convertase 2 enzyme. Remarkably, the same MIPs bound SARS-CoV-2 virus like particles with even higher affinity along with excellent discrimination of influenza A (H3N2) virus. While MIPs prepared with a truncated heptapeptide template GFNCYFP showed only a slightly decreased affinity for RBD, a single mismatch in the amino acid sequence of the template, i.e. the substitution of the central cysteine with a serine, fully suppressed the RBD binding. Y1 - 2021 U6 - https://doi.org/10.1039/d1sc04502d SN - 2041-6539 VL - 13 IS - 5 SP - 1263 EP - 1269 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Bogdanovskaya, V. A. A1 - Fridman, Vadim A1 - Tarasevich, M. R. A1 - Scheller, Frieder W. T1 - Bioelectrocatalysis by immobilized peroxidase : the reaction mechanism and the possibility of electroanalytical detection of both inhibitors and activators of enzyme Y1 - 1994 ER - TY - JOUR A1 - Bistolas, Nikitas A1 - Wollenberger, Ursula A1 - Jung, Christiane A1 - Scheller, Frieder W. T1 - Cytochrome P450 biosensors : a review N2 - Cytochrome P450 (CYP) is a large family of enzymes containing heme as the active site. Since their discovery and the elucidation of their structure, they have attracted the interest of scientist for many years, particularly due to their catalytic abilities. Since the late 1970s attempts have concentrated on the construction and development of electrochemical sensors. Although sensors based on mediated electron transfer have also been constructed, the direct electron transfer approach has attracted most of the interest. This has enabled the investigation of the electrochemical properties of the various isoforms of CYP. Furthermore, CYP utilized to construct biosensors for the determination of substrates important in environmental monitoring, pharmaceutical industry and clinical practice. (c) 2004 Elsevier B. V. All rights reserved Y1 - 2005 ER - TY - JOUR A1 - Bistolas, Nikitas A1 - Christenson, A. A1 - Ruzgas, T. A1 - Jung, Christiane A1 - Scheller, Frieder W. A1 - Wollenberger, Ursula T1 - Spectroelectrochemistry of cytochrome P450cam N2 - The spectroelectrochemistry of camphor-bound cytochrome P450cam (P450cam) using gold electrodes is described. The electrodes were modified with either 4,4'-dithiodipyridin or sodium dithionite. Electrolysis of P450cam was carried out when the enzyme was in solution, while at the same time UV visible absorption spectra were recorded. Reversible oxidation and reduction could be observed with both 4,4'-dithiodipyridin and dithionite modified electrodes. A formal potential (E-0') of -373 mV vs Ag/AgCl 1 M KCl was determined. The spectra of P450cam complexed with either carbon monoxide or metyrapone, both being inhibitors of P450 catalysis, clearly indicated that the protein retained its native state in the electrochemical cell during electrolysis. (C) 2003 Elsevier Inc. All rights reserved Y1 - 2004 ER - TY - JOUR A1 - Bier, Frank Fabian A1 - Scheller, Frieder W. T1 - Label-free observation of DNA-hybridisation and endonuclease activity on a wave guide surface using a grating coupler Y1 - 1996 ER - TY - JOUR A1 - Bier, Frank Fabian A1 - Kleinjung, Frank A1 - Scheller, Frieder W. T1 - Real time measurement of nucleic acid hybridization using evanescent wave sensors - step towards the genosensor Y1 - 1997 ER - TY - JOUR A1 - Bier, Frank Fabian A1 - Ehrentreich-Förster, Eva A1 - Scheller, Frieder W. A1 - Makower, Alexander A1 - Eremenko, A. V. A1 - Wollenberger, Ursula A1 - Bauer, Christian G. A1 - Pfeiffer, Dorothea A1 - Micheel, Burkhard T1 - Ultrasensitive biosensors Y1 - 1996 ER - TY - JOUR A1 - Bier, Frank Fabian A1 - Ehrentreich-Förster, Eva A1 - Scheller, Frieder W. T1 - Amplifying bienzyme cycle-linked immunoassays for determination of 2,4- dichlorphenoxyacetic acid Y1 - 1996 ER - TY - JOUR A1 - Bier, Frank Fabian A1 - Ehrentreich-Förster, Eva A1 - Makower, Alexander A1 - Scheller, Frieder W. T1 - An enzymatic amplification cycle for high sensitive immunoassay Y1 - 1996 ER - TY - JOUR A1 - Bier, Frank Fabian A1 - Ehrentreich-Förster, Eva A1 - Dölling, R. A1 - Eremenko, A. V. A1 - Scheller, Frieder W. T1 - A redox-label immunosensor on basis of a bi-enzyme electrode Y1 - 1997 ER - TY - JOUR A1 - Bier, Frank Fabian A1 - Ehrentreich-Förster, Eva A1 - Bauer, Christian G. A1 - Scheller, Frieder W. T1 - High sensitive competitive immunodetection of 2,4-dichlorophenoxyacetic acid using enzymatic amplification with electrochemical detection Y1 - 1996 ER - TY - THES A1 - Benkert, Alexander A1 - Scheller, Frieder W. A1 - Schössler, W. A1 - Micheel, Burkhard A1 - Warsinke, Axel T1 - Size exclusion redox-labeled immunoassay (SERI) : a new format for homogeneous amperometric creatinine determination Y1 - 2000 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 - 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 - 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 - 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 - 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 -