@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}
}
@article{ZhangCasertaYarmanetal.2021,
  author    = {Zhang, Xiaorong and Caserta, Giorgio and Yarman, Aysu and Supala, Eszter and Tadjoung Waffo, Armel Franklin and Wollenberger, Ulla and Gyurcsanyi, Robert E. and Zebger, Ingo and Scheller, Frieder W.},
  title     = {"Out of Pocket" protein binding},
  series = {Chemosensors},
  volume    = {9},
  journal   = {Chemosensors},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2227-9040},
  doi       = {10.3390/chemosensors9060128},
  pages     = {13},
  year      = {2021},
  abstract  = {The epitope imprinting approach applies exposed peptides as templates to synthesize Molecularly Imprinted Polymers (MIPs) for the recognition of the parent protein. While generally the template protein binding to such MIPs is considered to occur via the epitope-shaped cavities, unspecific interactions of the analyte with non-imprinted polymer as well as the detection method used may add to the complexity and interpretation of the target rebinding. To get new insights on the effects governing the rebinding of analytes, we electrosynthesized two epitope-imprinted polymers using the N-terminal pentapeptide VHLTP-amide of human hemoglobin (HbA) as the template. MIPs were prepared either by single-step electrosynthesis of scopoletin/pentapeptide mixtures or electropolymerization was performed after chemisorption of the cysteine extended VHLTP peptide. Rebinding of the target peptide and the parent HbA protein to the MIP nanofilms was quantified by square wave voltammetry using a redox probe gating, surface enhanced infrared absorption spectroscopy, and atomic force microscopy. While binding of the pentapeptide shows large influence of the amino acid sequence, all three methods revealed strong non-specific binding of HbA to both polyscopoletin-based MIPs with even higher affinities than the target peptides.},
  language  = {en}
}
@article{YarmanKurbanoğluZebgeretal.2021,
  author    = {Yarman, Aysu and Kurbanoğlu, Sevin{\c{c}} and Zebger, Ingo and Scheller, Frieder W.},
  title     = {Simple and robust},
  series = {Sensors and actuators : B, Chemical : an international journal devoted to research and development of chemical transducers},
  volume    = {330},
  journal   = {Sensors and actuators : B, Chemical : an international journal devoted to research and development of chemical transducers},
  publisher = {Elsevier Science},
  address   = {Amsterdam [u.a.]},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2020.129369},
  pages     = {12},
  year      = {2021},
  abstract  = {A spectrum of 7562 publications on Molecularly Imprinted Polymers (MIPs) has been presented in literature within the last ten years (Scopus, September 7, 2020). Around 10 \% of the papers published on MIPs describe the recognition of proteins. The straightforward synthesis of MIPs is a significant advantage as compared with the preparation of enzymes or antibodies. MIPs have been synthesized from only one up to six functional monomers while proteins are made up of 20 natural amino acids. Furthermore, they can be synthesized against structures of low immunogenicity and allow multi-analyte measurements via multi-target synthesis. Electrochemical methods allow simple polymer synthesis, removal of the template and readout. Among the different sensor configurations electrochemical MIP-sensors provide the broadest spectrum of protein analytes. The sensitivity of MIP-sensors is sufficiently high for biomarkers in the sub-nanomolar region, nevertheless the cross-reactivity of highly abundant proteins in human serum is still a challenge. MIPs for proteins offer innovative tools not only for clinical and environmental analysis, but also for bioimaging, therapy and protein engineering.},
  language  = {en}
}
@article{TadjoungWaffoYesildagCasertaetal.2018,
  author    = {Tadjoung Waffo, Armel Franklin and Yesildag, Cigdem and Caserta, Giorgio and Katz, Sagie and Zebger, Ingo and Lensen, Marga C. and Wollenberger, Ulla and Scheller, Frieder W. and Altintas, Zeynep},
  title     = {Fully electrochemical MIP sensor for artemisinin},
  series = {Sensors and actuators : B, Chemical},
  volume    = {275},
  journal   = {Sensors and actuators : B, Chemical},
  publisher = {Elsevier},
  address   = {Lausanne},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2018.08.018},
  pages     = {163 -- 173},
  year      = {2018},
  abstract  = {This study aims to develop a rapid, sensitive and cost-effective biomimetic electrochemical sensor for artemisinin determination in plant extracts and for pharmacokinetic studies. A novel molecularly imprinted polymer (MIP)based electrochemical sensor was developed by electropolymerization of o-phenylenediamine (o-PD) in the presence of artemisinin on gold wire surface for sensitive detection of artemisinin. The experimental parameters, including selection of functional monomer, polymerization conditions, template extraction after polymerization, influence of pH and buffer were all optimized. Every step of imprinted film synthesis were evaluated by employing voltammetry techniques, surface-enhanced infrared absorption spectroscopy (SEIRAS) and atomic force microscopy (AFM). The specificity was further evaluated by investigating non-specific artemisinin binding on non-imprinted polymer (NIP) surfaces and an imprinting factor of 6.8 was achieved. The artemisinin imprinted polymers using o-PD as functional monomer have provided highly stable and effective binding cavities for artemisinin. Cross-reactivity studies with drug molecules showed that the MIPs are highly specific for artemisinin. The influence of matrix effect was further investigated both in artificial plant matrix and diluted human serum. The results revealed a high affinity of artemisinin-MIP with dissociation constant of 7.3 x 10(-9) M and with a detection limit of 0.01 mu M and 0.02 mu M in buffer and plant matrix, respectively.},
  language  = {en}
}
@article{LaunDuffusWahlefeldetal.2022,
  author    = {Laun, Konstantin and Duffus, Benjamin R. and Wahlefeld, Stefan and Katz, Sagie and Belger, Dennis Heinz and Hildebrandt, Peter and Mroginski, Maria Andrea and Leimk{\"u}hler, Silke and Zebger, Ingo},
  title     = {Infrared spectroscopy flucidates the inhibitor binding sites in a metal-dependent formate dehydrogenase},
  series = {Chemistry - a European journal},
  journal   = {Chemistry - a European journal},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0947-6539},
  doi       = {10.1002/chem.202201091},
  pages     = {8},
  year      = {2022},
  abstract  = {Biological carbon dioxide (CO2) reduction is an important step by which organisms form valuable energy-richer molecules required for further metabolic processes. The Mo-dependent formate dehydrogenase (FDH) from Rhodobacter capsulatus catalyzes reversible formate oxidation to CO2 at a bis-molybdopterin guanine dinucleotide (bis-MGD) cofactor. To elucidate potential substrate binding sites relevant for the mechanism, we studied herein the interaction with the inhibitory molecules azide and cyanate, which are isoelectronic to CO2 and charged as formate. We employed infrared (IR) spectroscopy in combination with density functional theory (DFT) and inhibition kinetics. One distinct inhibitory molecule was found to bind to either a non-competitive or a competitive binding site in the secondary coordination sphere of the active site. Site-directed mutagenesis of key amino acid residues in the vicinity of the bis-MGD cofactor revealed changes in both non-competitive and competitive binding, whereby the inhibitor is in case of the latter interaction presumably bound between the cofactor and the adjacent Arg587.},
  language  = {en}
}
@article{KielbSezerKatzetal.2015,
  author    = {Kielb, Patrycja and Sezer, Murat and Katz, Sagie and Lopez, Francesca and Schulz, Christopher and Gorton, Lo and Ludwig, Roland and Wollenberger, Ursula and Zebger, Ingo and Weidinger, Inez M.},
  title     = {Spectroscopic Observation of Calcium-Induced Reorientation of Cellobiose Dehydrogenase Immobilized on Electrodes and its Effect on Electrocatalytic Activity},
  series = {ChemPhysChem : a European journal of chemical physics and physical chemistry},
  volume    = {16},
  journal   = {ChemPhysChem : a European journal of chemical physics and physical chemistry},
  number    = {9},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1439-4235},
  doi       = {10.1002/cphc.201500112},
  pages     = {1960 -- 1968},
  year      = {2015},
  abstract  = {Cellobiose dehydrogenase catalyzes the oxidation of various carbohydrates and is considered as a possible anode catalyst in biofuel cells. It has been shown that the catalytic performance of this enzyme immobilized on electrodes can be increased by presence of calcium ions. To get insight into the Ca2+-induced changes in the immobilized enzyme we employ surface-enhanced vibrational (SERR and SEIRA) spectroscopy together with electrochemistry. Upon addition of Ca2+ ions electrochemical measurements show a shift of the catalytic turnover signal to more negative potentials while SERR measurements reveal an offset between the potential of heme reduction and catalytic current. Comparing SERR and SEIRA data we propose that binding of Ca2+ to the heme induces protein reorientation in a way that the electron transfer pathway of the catalytic FAD center to the electrode can bypass the heme cofactor, resulting in catalytic activity at more negative potentials.},
  language  = {en}
}
@article{CasertaZhangYarmanetal.2021,
  author    = {Caserta, Giorgio and Zhang, Xiaorong and Yarman, Aysu and Supala, Eszter and Wollenberger, Ulla and Gyurcs{\´a}nyi, R{\´o}bert E. and Zebger, Ingo and Scheller, Frieder W.},
  title     = {Insights in electrosynthesis, target binding, and stability of peptide-imprinted polymer nanofilms},
  series = {Electrochimica acta : the journal of the International Society of Electrochemistry (ISE)},
  volume    = {381},
  journal   = {Electrochimica acta : the journal of the International Society of Electrochemistry (ISE)},
  publisher = {Elsevier},
  address   = {New York, NY [u.a.]},
  issn      = {0013-4686},
  doi       = {10.1016/j.electacta.2021.138236},
  pages     = {8},
  year      = {2021},
  abstract  = {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.},
  language  = {en}
}