@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{LettauWarsinkeKatterleetal.2006, author = {Lettau, Kristian and Warsinke, Axel and Katterle, Martin and Danielsson, Bengt and Scheller, Frieder W.}, title = {A bifunctional molecularly imprinted polymer (MIP): analysis of binding and catalysis by a thermistor}, doi = {10.1002/anie.200601796}, year = {2006}, abstract = {Binding or catalysis? Both can be distinguished with a molecularly imprinted polymer (MIP) by the different patterns of heat generation. The catalytically active sites, like in the corresponding enzyme, generate a steady-state temperature increase. Thus, enzyme-like catalysis and antibody-analogue binding are analyzed simultaneously in a bifunctional MIP for the first time (see scheme).}, language = {en} } @article{LiuWollenbergerKatterleetal.2006, author = {Liu, Songqin and Wollenberger, Ursula and Katterle, Martin and Scheller, Frieder W.}, title = {Ferroceneboronic acid-based amperometric biosensor for glycated hemoglobin}, issn = {0925-4005}, doi = {10.1016/j.snb.2005.07.011}, year = {2006}, abstract = {An amperometric biosensor for the determination of glycated hemoglobin in human whole blood is proposed. The principle is based on the electrochemical measurement of ferroceneboronic acid (FcBA) that has been specifically bound to the glycated N-terminus. Hemoglobin is immobilized on a zirconium dioxide nanoparticle modified pyrolytic graphite electrode (PGE) in the presence of didodecyldimethylammonium bromide (DDAB). The incubation of this sensor in FcBA solution leads to the formation of an FcBA-modified surface due to the affinity interaction between boronate and the glycated sites of the hemoglobin. The binding of FcBA results in well-defined redox peaks with an E-0' of 0.299 V versus Ag/AgCl (1 M KCl). The square wave voltammetric response of the bound FcBA reflects the amount of glycated hemoglobin at the surface. This signal increases linearily with the degree of glycated hemoglobin from 6.8 to 14.0\% of total immobilized hemoglobin. The scheme was applied to the determination of the fraction of glycated hemoglobin in whole blood samples.}, language = {en} } @article{LoewBogdanoffHerrmannetal.2006, author = {Loew, Noya and Bogdanoff, Peter and Herrmann, Iris and Wollenberger, Ursula and Scheller, Frieder W. and Katterle, Martin}, title = {Influence of modifications on the efficiency of pyrolysed CoTMPP as electrode material for horseradish peroxidase and the reduction of hydrogen peroxide}, series = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis}, volume = {18}, journal = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis}, number = {23}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1040-0397}, doi = {10.1002/elan.200603664}, pages = {2324 -- 2330}, year = {2006}, abstract = {A tailor-made horseradish peroxidase (HRP) bulk composite electrode was developed on the basis of pyrolyzed cobalt tetramethoxyphenylporphyrin (CoTMPP) by modifying pore size and surface area of the porous carbon material through varying amounts of iron oxalate and sulfur prior to pyrolyzation. The materials were used to immobilize horseradish peroxidase (HRP). These electrodes were characterized in terms of their efficiency to reduce hydrogen peroxide. The heterogeneous electron transfer rate constants of different materials were determined with the rotating disk electrode method and a k(S) (401 +/- 61 s(-1)) exceeding previously reported values for native HRP was found.}, 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{SchellerBistolasLiuetal.2005, author = {Scheller, Frieder W. and Bistolas, Nikitas and Liu, Songqin and J{\"a}nchen, Michael and Katterle, Martin and Wollenberger, Ursula}, title = {Thirty years of haemoglobin electrochemistry}, year = {2005}, abstract = {Electrochemical investigations of the blood oxygen carrier protein include both mediated and direct electron transfer. The reaction of haemoglobin (Hb) with typical mediators, e.g., ferricyanide, can be quantified by measuring the produced ferrocyanide which is equivalent to the Hb concentration. Immobilization of the mediator within the electrode body allows reagentless electrochemical measuring of Hb. On the other hand, entrapment of the protein within layers of polyclectrolytes, lipids, nanoparticles of clay or gold leads to a fast heterogeneous electron exchange of the partially denatured Hb. (c) 2005 Elsevier B.V. All rights reserved}, language = {en} }